1ea272257SMauro Carvalho Chehab================ 2ea272257SMauro Carvalho ChehabEvent Histograms 3ea272257SMauro Carvalho Chehab================ 4ea272257SMauro Carvalho Chehab 5ea272257SMauro Carvalho ChehabDocumentation written by Tom Zanussi 6ea272257SMauro Carvalho Chehab 7ea272257SMauro Carvalho Chehab1. Introduction 8ea272257SMauro Carvalho Chehab=============== 9ea272257SMauro Carvalho Chehab 10ea272257SMauro Carvalho Chehab Histogram triggers are special event triggers that can be used to 11ea272257SMauro Carvalho Chehab aggregate trace event data into histograms. For information on 12ea272257SMauro Carvalho Chehab trace events and event triggers, see Documentation/trace/events.rst. 13ea272257SMauro Carvalho Chehab 14ea272257SMauro Carvalho Chehab 15ea272257SMauro Carvalho Chehab2. Histogram Trigger Command 16ea272257SMauro Carvalho Chehab============================ 17ea272257SMauro Carvalho Chehab 18ea272257SMauro Carvalho Chehab A histogram trigger command is an event trigger command that 19ea272257SMauro Carvalho Chehab aggregates event hits into a hash table keyed on one or more trace 20ea272257SMauro Carvalho Chehab event format fields (or stacktrace) and a set of running totals 21ea272257SMauro Carvalho Chehab derived from one or more trace event format fields and/or event 22ea272257SMauro Carvalho Chehab counts (hitcount). 23ea272257SMauro Carvalho Chehab 24ea272257SMauro Carvalho Chehab The format of a hist trigger is as follows:: 25ea272257SMauro Carvalho Chehab 26ea272257SMauro Carvalho Chehab hist:keys=<field1[,field2,...]>[:values=<field1[,field2,...]>] 27ea272257SMauro Carvalho Chehab [:sort=<field1[,field2,...]>][:size=#entries][:pause][:continue] 28ea272257SMauro Carvalho Chehab [:clear][:name=histname1] [if <filter>] 29ea272257SMauro Carvalho Chehab 30ea272257SMauro Carvalho Chehab When a matching event is hit, an entry is added to a hash table 31ea272257SMauro Carvalho Chehab using the key(s) and value(s) named. Keys and values correspond to 32ea272257SMauro Carvalho Chehab fields in the event's format description. Values must correspond to 33ea272257SMauro Carvalho Chehab numeric fields - on an event hit, the value(s) will be added to a 34ea272257SMauro Carvalho Chehab sum kept for that field. The special string 'hitcount' can be used 35ea272257SMauro Carvalho Chehab in place of an explicit value field - this is simply a count of 36ea272257SMauro Carvalho Chehab event hits. If 'values' isn't specified, an implicit 'hitcount' 37ea272257SMauro Carvalho Chehab value will be automatically created and used as the only value. 38ea272257SMauro Carvalho Chehab Keys can be any field, or the special string 'stacktrace', which 39ea272257SMauro Carvalho Chehab will use the event's kernel stacktrace as the key. The keywords 40ea272257SMauro Carvalho Chehab 'keys' or 'key' can be used to specify keys, and the keywords 41ea272257SMauro Carvalho Chehab 'values', 'vals', or 'val' can be used to specify values. Compound 42ea272257SMauro Carvalho Chehab keys consisting of up to two fields can be specified by the 'keys' 43ea272257SMauro Carvalho Chehab keyword. Hashing a compound key produces a unique entry in the 44ea272257SMauro Carvalho Chehab table for each unique combination of component keys, and can be 45ea272257SMauro Carvalho Chehab useful for providing more fine-grained summaries of event data. 46ea272257SMauro Carvalho Chehab Additionally, sort keys consisting of up to two fields can be 47ea272257SMauro Carvalho Chehab specified by the 'sort' keyword. If more than one field is 48ea272257SMauro Carvalho Chehab specified, the result will be a 'sort within a sort': the first key 49ea272257SMauro Carvalho Chehab is taken to be the primary sort key and the second the secondary 50ea272257SMauro Carvalho Chehab key. If a hist trigger is given a name using the 'name' parameter, 51ea272257SMauro Carvalho Chehab its histogram data will be shared with other triggers of the same 52ea272257SMauro Carvalho Chehab name, and trigger hits will update this common data. Only triggers 53ea272257SMauro Carvalho Chehab with 'compatible' fields can be combined in this way; triggers are 54ea272257SMauro Carvalho Chehab 'compatible' if the fields named in the trigger share the same 55ea272257SMauro Carvalho Chehab number and type of fields and those fields also have the same names. 56ea272257SMauro Carvalho Chehab Note that any two events always share the compatible 'hitcount' and 57ea272257SMauro Carvalho Chehab 'stacktrace' fields and can therefore be combined using those 58ea272257SMauro Carvalho Chehab fields, however pointless that may be. 59ea272257SMauro Carvalho Chehab 60ea272257SMauro Carvalho Chehab 'hist' triggers add a 'hist' file to each event's subdirectory. 61ea272257SMauro Carvalho Chehab Reading the 'hist' file for the event will dump the hash table in 62ea272257SMauro Carvalho Chehab its entirety to stdout. If there are multiple hist triggers 63ea272257SMauro Carvalho Chehab attached to an event, there will be a table for each trigger in the 64ea272257SMauro Carvalho Chehab output. The table displayed for a named trigger will be the same as 65ea272257SMauro Carvalho Chehab any other instance having the same name. Each printed hash table 66ea272257SMauro Carvalho Chehab entry is a simple list of the keys and values comprising the entry; 67ea272257SMauro Carvalho Chehab keys are printed first and are delineated by curly braces, and are 68ea272257SMauro Carvalho Chehab followed by the set of value fields for the entry. By default, 69ea272257SMauro Carvalho Chehab numeric fields are displayed as base-10 integers. This can be 70ea272257SMauro Carvalho Chehab modified by appending any of the following modifiers to the field 71ea272257SMauro Carvalho Chehab name: 72ea272257SMauro Carvalho Chehab 73ea272257SMauro Carvalho Chehab =========== ========================================== 74ea272257SMauro Carvalho Chehab .hex display a number as a hex value 75ea272257SMauro Carvalho Chehab .sym display an address as a symbol 76ea272257SMauro Carvalho Chehab .sym-offset display an address as a symbol and offset 77ea272257SMauro Carvalho Chehab .syscall display a syscall id as a system call name 78ea272257SMauro Carvalho Chehab .execname display a common_pid as a program name 79ea272257SMauro Carvalho Chehab .log2 display log2 value rather than raw number 80ea272257SMauro Carvalho Chehab .usecs display a common_timestamp in microseconds 81ea272257SMauro Carvalho Chehab =========== ========================================== 82ea272257SMauro Carvalho Chehab 83ea272257SMauro Carvalho Chehab Note that in general the semantics of a given field aren't 84ea272257SMauro Carvalho Chehab interpreted when applying a modifier to it, but there are some 85ea272257SMauro Carvalho Chehab restrictions to be aware of in this regard: 86ea272257SMauro Carvalho Chehab 87ea272257SMauro Carvalho Chehab - only the 'hex' modifier can be used for values (because values 88ea272257SMauro Carvalho Chehab are essentially sums, and the other modifiers don't make sense 89ea272257SMauro Carvalho Chehab in that context). 90ea272257SMauro Carvalho Chehab - the 'execname' modifier can only be used on a 'common_pid'. The 91ea272257SMauro Carvalho Chehab reason for this is that the execname is simply the 'comm' value 92ea272257SMauro Carvalho Chehab saved for the 'current' process when an event was triggered, 93ea272257SMauro Carvalho Chehab which is the same as the common_pid value saved by the event 94ea272257SMauro Carvalho Chehab tracing code. Trying to apply that comm value to other pid 95ea272257SMauro Carvalho Chehab values wouldn't be correct, and typically events that care save 96ea272257SMauro Carvalho Chehab pid-specific comm fields in the event itself. 97ea272257SMauro Carvalho Chehab 98ea272257SMauro Carvalho Chehab A typical usage scenario would be the following to enable a hist 99ea272257SMauro Carvalho Chehab trigger, read its current contents, and then turn it off:: 100ea272257SMauro Carvalho Chehab 101ea272257SMauro Carvalho Chehab # echo 'hist:keys=skbaddr.hex:vals=len' > \ 102ea272257SMauro Carvalho Chehab /sys/kernel/debug/tracing/events/net/netif_rx/trigger 103ea272257SMauro Carvalho Chehab 104ea272257SMauro Carvalho Chehab # cat /sys/kernel/debug/tracing/events/net/netif_rx/hist 105ea272257SMauro Carvalho Chehab 106ea272257SMauro Carvalho Chehab # echo '!hist:keys=skbaddr.hex:vals=len' > \ 107ea272257SMauro Carvalho Chehab /sys/kernel/debug/tracing/events/net/netif_rx/trigger 108ea272257SMauro Carvalho Chehab 109ea272257SMauro Carvalho Chehab The trigger file itself can be read to show the details of the 110ea272257SMauro Carvalho Chehab currently attached hist trigger. This information is also displayed 111ea272257SMauro Carvalho Chehab at the top of the 'hist' file when read. 112ea272257SMauro Carvalho Chehab 113ea272257SMauro Carvalho Chehab By default, the size of the hash table is 2048 entries. The 'size' 114ea272257SMauro Carvalho Chehab parameter can be used to specify more or fewer than that. The units 115ea272257SMauro Carvalho Chehab are in terms of hashtable entries - if a run uses more entries than 116ea272257SMauro Carvalho Chehab specified, the results will show the number of 'drops', the number 117ea272257SMauro Carvalho Chehab of hits that were ignored. The size should be a power of 2 between 118ea272257SMauro Carvalho Chehab 128 and 131072 (any non- power-of-2 number specified will be rounded 119ea272257SMauro Carvalho Chehab up). 120ea272257SMauro Carvalho Chehab 121ea272257SMauro Carvalho Chehab The 'sort' parameter can be used to specify a value field to sort 122ea272257SMauro Carvalho Chehab on. The default if unspecified is 'hitcount' and the default sort 123ea272257SMauro Carvalho Chehab order is 'ascending'. To sort in the opposite direction, append 124ea272257SMauro Carvalho Chehab .descending' to the sort key. 125ea272257SMauro Carvalho Chehab 126ea272257SMauro Carvalho Chehab The 'pause' parameter can be used to pause an existing hist trigger 127ea272257SMauro Carvalho Chehab or to start a hist trigger but not log any events until told to do 128ea272257SMauro Carvalho Chehab so. 'continue' or 'cont' can be used to start or restart a paused 129ea272257SMauro Carvalho Chehab hist trigger. 130ea272257SMauro Carvalho Chehab 131ea272257SMauro Carvalho Chehab The 'clear' parameter will clear the contents of a running hist 132ea272257SMauro Carvalho Chehab trigger and leave its current paused/active state. 133ea272257SMauro Carvalho Chehab 134ea272257SMauro Carvalho Chehab Note that the 'pause', 'cont', and 'clear' parameters should be 135ea272257SMauro Carvalho Chehab applied using 'append' shell operator ('>>') if applied to an 136ea272257SMauro Carvalho Chehab existing trigger, rather than via the '>' operator, which will cause 137ea272257SMauro Carvalho Chehab the trigger to be removed through truncation. 138ea272257SMauro Carvalho Chehab 139ea272257SMauro Carvalho Chehab- enable_hist/disable_hist 140ea272257SMauro Carvalho Chehab 141ea272257SMauro Carvalho Chehab The enable_hist and disable_hist triggers can be used to have one 142ea272257SMauro Carvalho Chehab event conditionally start and stop another event's already-attached 143ea272257SMauro Carvalho Chehab hist trigger. Any number of enable_hist and disable_hist triggers 144ea272257SMauro Carvalho Chehab can be attached to a given event, allowing that event to kick off 145ea272257SMauro Carvalho Chehab and stop aggregations on a host of other events. 146ea272257SMauro Carvalho Chehab 147ea272257SMauro Carvalho Chehab The format is very similar to the enable/disable_event triggers:: 148ea272257SMauro Carvalho Chehab 149ea272257SMauro Carvalho Chehab enable_hist:<system>:<event>[:count] 150ea272257SMauro Carvalho Chehab disable_hist:<system>:<event>[:count] 151ea272257SMauro Carvalho Chehab 152ea272257SMauro Carvalho Chehab Instead of enabling or disabling the tracing of the target event 153ea272257SMauro Carvalho Chehab into the trace buffer as the enable/disable_event triggers do, the 154ea272257SMauro Carvalho Chehab enable/disable_hist triggers enable or disable the aggregation of 155ea272257SMauro Carvalho Chehab the target event into a hash table. 156ea272257SMauro Carvalho Chehab 157ea272257SMauro Carvalho Chehab A typical usage scenario for the enable_hist/disable_hist triggers 158ea272257SMauro Carvalho Chehab would be to first set up a paused hist trigger on some event, 159ea272257SMauro Carvalho Chehab followed by an enable_hist/disable_hist pair that turns the hist 160ea272257SMauro Carvalho Chehab aggregation on and off when conditions of interest are hit:: 161ea272257SMauro Carvalho Chehab 162ea272257SMauro Carvalho Chehab # echo 'hist:keys=skbaddr.hex:vals=len:pause' > \ 163ea272257SMauro Carvalho Chehab /sys/kernel/debug/tracing/events/net/netif_receive_skb/trigger 164ea272257SMauro Carvalho Chehab 165ea272257SMauro Carvalho Chehab # echo 'enable_hist:net:netif_receive_skb if filename==/usr/bin/wget' > \ 166ea272257SMauro Carvalho Chehab /sys/kernel/debug/tracing/events/sched/sched_process_exec/trigger 167ea272257SMauro Carvalho Chehab 168ea272257SMauro Carvalho Chehab # echo 'disable_hist:net:netif_receive_skb if comm==wget' > \ 169ea272257SMauro Carvalho Chehab /sys/kernel/debug/tracing/events/sched/sched_process_exit/trigger 170ea272257SMauro Carvalho Chehab 171ea272257SMauro Carvalho Chehab The above sets up an initially paused hist trigger which is unpaused 172ea272257SMauro Carvalho Chehab and starts aggregating events when a given program is executed, and 173ea272257SMauro Carvalho Chehab which stops aggregating when the process exits and the hist trigger 174ea272257SMauro Carvalho Chehab is paused again. 175ea272257SMauro Carvalho Chehab 176ea272257SMauro Carvalho Chehab The examples below provide a more concrete illustration of the 177ea272257SMauro Carvalho Chehab concepts and typical usage patterns discussed above. 178ea272257SMauro Carvalho Chehab 179ea272257SMauro Carvalho Chehab'special' event fields 180ea272257SMauro Carvalho Chehab------------------------ 181ea272257SMauro Carvalho Chehab 182ea272257SMauro Carvalho Chehab There are a number of 'special event fields' available for use as 183ea272257SMauro Carvalho Chehab keys or values in a hist trigger. These look like and behave as if 184ea272257SMauro Carvalho Chehab they were actual event fields, but aren't really part of the event's 185ea272257SMauro Carvalho Chehab field definition or format file. They are however available for any 186ea272257SMauro Carvalho Chehab event, and can be used anywhere an actual event field could be. 187ea272257SMauro Carvalho Chehab They are: 188ea272257SMauro Carvalho Chehab 189ea272257SMauro Carvalho Chehab ====================== ==== ======================================= 190ea272257SMauro Carvalho Chehab common_timestamp u64 timestamp (from ring buffer) associated 191ea272257SMauro Carvalho Chehab with the event, in nanoseconds. May be 192ea272257SMauro Carvalho Chehab modified by .usecs to have timestamps 193ea272257SMauro Carvalho Chehab interpreted as microseconds. 194ea272257SMauro Carvalho Chehab cpu int the cpu on which the event occurred. 195ea272257SMauro Carvalho Chehab ====================== ==== ======================================= 196ea272257SMauro Carvalho Chehab 197ea272257SMauro Carvalho ChehabExtended error information 198ea272257SMauro Carvalho Chehab-------------------------- 199ea272257SMauro Carvalho Chehab 200ea272257SMauro Carvalho Chehab For some error conditions encountered when invoking a hist trigger 201ea272257SMauro Carvalho Chehab command, extended error information is available via the 202ea272257SMauro Carvalho Chehab corresponding event's 'hist' file. Reading the hist file after an 203ea272257SMauro Carvalho Chehab error will display more detailed information about what went wrong, 204ea272257SMauro Carvalho Chehab if information is available. This extended error information will 205ea272257SMauro Carvalho Chehab be available until the next hist trigger command for that event. 206ea272257SMauro Carvalho Chehab 207ea272257SMauro Carvalho Chehab If available for a given error condition, the extended error 208ea272257SMauro Carvalho Chehab information and usage takes the following form:: 209ea272257SMauro Carvalho Chehab 210ea272257SMauro Carvalho Chehab # echo xxx > /sys/kernel/debug/tracing/events/sched/sched_wakeup/trigger 211ea272257SMauro Carvalho Chehab echo: write error: Invalid argument 212ea272257SMauro Carvalho Chehab 213ea272257SMauro Carvalho Chehab # cat /sys/kernel/debug/tracing/events/sched/sched_wakeup/hist 214ea272257SMauro Carvalho Chehab ERROR: Couldn't yyy: zzz 215ea272257SMauro Carvalho Chehab Last command: xxx 216ea272257SMauro Carvalho Chehab 217ea272257SMauro Carvalho Chehab6.2 'hist' trigger examples 218ea272257SMauro Carvalho Chehab--------------------------- 219ea272257SMauro Carvalho Chehab 220ea272257SMauro Carvalho Chehab The first set of examples creates aggregations using the kmalloc 221ea272257SMauro Carvalho Chehab event. The fields that can be used for the hist trigger are listed 222ea272257SMauro Carvalho Chehab in the kmalloc event's format file:: 223ea272257SMauro Carvalho Chehab 224ea272257SMauro Carvalho Chehab # cat /sys/kernel/debug/tracing/events/kmem/kmalloc/format 225ea272257SMauro Carvalho Chehab name: kmalloc 226ea272257SMauro Carvalho Chehab ID: 374 227ea272257SMauro Carvalho Chehab format: 228ea272257SMauro Carvalho Chehab field:unsigned short common_type; offset:0; size:2; signed:0; 229ea272257SMauro Carvalho Chehab field:unsigned char common_flags; offset:2; size:1; signed:0; 230ea272257SMauro Carvalho Chehab field:unsigned char common_preempt_count; offset:3; size:1; signed:0; 231ea272257SMauro Carvalho Chehab field:int common_pid; offset:4; size:4; signed:1; 232ea272257SMauro Carvalho Chehab 233ea272257SMauro Carvalho Chehab field:unsigned long call_site; offset:8; size:8; signed:0; 234ea272257SMauro Carvalho Chehab field:const void * ptr; offset:16; size:8; signed:0; 235ea272257SMauro Carvalho Chehab field:size_t bytes_req; offset:24; size:8; signed:0; 236ea272257SMauro Carvalho Chehab field:size_t bytes_alloc; offset:32; size:8; signed:0; 237ea272257SMauro Carvalho Chehab field:gfp_t gfp_flags; offset:40; size:4; signed:0; 238ea272257SMauro Carvalho Chehab 239ea272257SMauro Carvalho Chehab We'll start by creating a hist trigger that generates a simple table 240ea272257SMauro Carvalho Chehab that lists the total number of bytes requested for each function in 241ea272257SMauro Carvalho Chehab the kernel that made one or more calls to kmalloc:: 242ea272257SMauro Carvalho Chehab 243ea272257SMauro Carvalho Chehab # echo 'hist:key=call_site:val=bytes_req' > \ 244ea272257SMauro Carvalho Chehab /sys/kernel/debug/tracing/events/kmem/kmalloc/trigger 245ea272257SMauro Carvalho Chehab 246ea272257SMauro Carvalho Chehab This tells the tracing system to create a 'hist' trigger using the 247ea272257SMauro Carvalho Chehab call_site field of the kmalloc event as the key for the table, which 248ea272257SMauro Carvalho Chehab just means that each unique call_site address will have an entry 249ea272257SMauro Carvalho Chehab created for it in the table. The 'val=bytes_req' parameter tells 250ea272257SMauro Carvalho Chehab the hist trigger that for each unique entry (call_site) in the 251ea272257SMauro Carvalho Chehab table, it should keep a running total of the number of bytes 252ea272257SMauro Carvalho Chehab requested by that call_site. 253ea272257SMauro Carvalho Chehab 254ea272257SMauro Carvalho Chehab We'll let it run for awhile and then dump the contents of the 'hist' 255ea272257SMauro Carvalho Chehab file in the kmalloc event's subdirectory (for readability, a number 256ea272257SMauro Carvalho Chehab of entries have been omitted):: 257ea272257SMauro Carvalho Chehab 258ea272257SMauro Carvalho Chehab # cat /sys/kernel/debug/tracing/events/kmem/kmalloc/hist 259ea272257SMauro Carvalho Chehab # trigger info: hist:keys=call_site:vals=bytes_req:sort=hitcount:size=2048 [active] 260ea272257SMauro Carvalho Chehab 261ea272257SMauro Carvalho Chehab { call_site: 18446744072106379007 } hitcount: 1 bytes_req: 176 262ea272257SMauro Carvalho Chehab { call_site: 18446744071579557049 } hitcount: 1 bytes_req: 1024 263ea272257SMauro Carvalho Chehab { call_site: 18446744071580608289 } hitcount: 1 bytes_req: 16384 264ea272257SMauro Carvalho Chehab { call_site: 18446744071581827654 } hitcount: 1 bytes_req: 24 265ea272257SMauro Carvalho Chehab { call_site: 18446744071580700980 } hitcount: 1 bytes_req: 8 266ea272257SMauro Carvalho Chehab { call_site: 18446744071579359876 } hitcount: 1 bytes_req: 152 267ea272257SMauro Carvalho Chehab { call_site: 18446744071580795365 } hitcount: 3 bytes_req: 144 268ea272257SMauro Carvalho Chehab { call_site: 18446744071581303129 } hitcount: 3 bytes_req: 144 269ea272257SMauro Carvalho Chehab { call_site: 18446744071580713234 } hitcount: 4 bytes_req: 2560 270ea272257SMauro Carvalho Chehab { call_site: 18446744071580933750 } hitcount: 4 bytes_req: 736 271ea272257SMauro Carvalho Chehab . 272ea272257SMauro Carvalho Chehab . 273ea272257SMauro Carvalho Chehab . 274ea272257SMauro Carvalho Chehab { call_site: 18446744072106047046 } hitcount: 69 bytes_req: 5576 275ea272257SMauro Carvalho Chehab { call_site: 18446744071582116407 } hitcount: 73 bytes_req: 2336 276ea272257SMauro Carvalho Chehab { call_site: 18446744072106054684 } hitcount: 136 bytes_req: 140504 277ea272257SMauro Carvalho Chehab { call_site: 18446744072106224230 } hitcount: 136 bytes_req: 19584 278ea272257SMauro Carvalho Chehab { call_site: 18446744072106078074 } hitcount: 153 bytes_req: 2448 279ea272257SMauro Carvalho Chehab { call_site: 18446744072106062406 } hitcount: 153 bytes_req: 36720 280ea272257SMauro Carvalho Chehab { call_site: 18446744071582507929 } hitcount: 153 bytes_req: 37088 281ea272257SMauro Carvalho Chehab { call_site: 18446744072102520590 } hitcount: 273 bytes_req: 10920 282ea272257SMauro Carvalho Chehab { call_site: 18446744071582143559 } hitcount: 358 bytes_req: 716 283ea272257SMauro Carvalho Chehab { call_site: 18446744072106465852 } hitcount: 417 bytes_req: 56712 284ea272257SMauro Carvalho Chehab { call_site: 18446744072102523378 } hitcount: 485 bytes_req: 27160 285ea272257SMauro Carvalho Chehab { call_site: 18446744072099568646 } hitcount: 1676 bytes_req: 33520 286ea272257SMauro Carvalho Chehab 287ea272257SMauro Carvalho Chehab Totals: 288ea272257SMauro Carvalho Chehab Hits: 4610 289ea272257SMauro Carvalho Chehab Entries: 45 290ea272257SMauro Carvalho Chehab Dropped: 0 291ea272257SMauro Carvalho Chehab 292ea272257SMauro Carvalho Chehab The output displays a line for each entry, beginning with the key 293ea272257SMauro Carvalho Chehab specified in the trigger, followed by the value(s) also specified in 294ea272257SMauro Carvalho Chehab the trigger. At the beginning of the output is a line that displays 295ea272257SMauro Carvalho Chehab the trigger info, which can also be displayed by reading the 296ea272257SMauro Carvalho Chehab 'trigger' file:: 297ea272257SMauro Carvalho Chehab 298ea272257SMauro Carvalho Chehab # cat /sys/kernel/debug/tracing/events/kmem/kmalloc/trigger 299ea272257SMauro Carvalho Chehab hist:keys=call_site:vals=bytes_req:sort=hitcount:size=2048 [active] 300ea272257SMauro Carvalho Chehab 301ea272257SMauro Carvalho Chehab At the end of the output are a few lines that display the overall 302ea272257SMauro Carvalho Chehab totals for the run. The 'Hits' field shows the total number of 303ea272257SMauro Carvalho Chehab times the event trigger was hit, the 'Entries' field shows the total 304ea272257SMauro Carvalho Chehab number of used entries in the hash table, and the 'Dropped' field 305ea272257SMauro Carvalho Chehab shows the number of hits that were dropped because the number of 306ea272257SMauro Carvalho Chehab used entries for the run exceeded the maximum number of entries 307ea272257SMauro Carvalho Chehab allowed for the table (normally 0, but if not a hint that you may 308ea272257SMauro Carvalho Chehab want to increase the size of the table using the 'size' parameter). 309ea272257SMauro Carvalho Chehab 310ea272257SMauro Carvalho Chehab Notice in the above output that there's an extra field, 'hitcount', 311ea272257SMauro Carvalho Chehab which wasn't specified in the trigger. Also notice that in the 312ea272257SMauro Carvalho Chehab trigger info output, there's a parameter, 'sort=hitcount', which 313ea272257SMauro Carvalho Chehab wasn't specified in the trigger either. The reason for that is that 314ea272257SMauro Carvalho Chehab every trigger implicitly keeps a count of the total number of hits 315ea272257SMauro Carvalho Chehab attributed to a given entry, called the 'hitcount'. That hitcount 316ea272257SMauro Carvalho Chehab information is explicitly displayed in the output, and in the 317ea272257SMauro Carvalho Chehab absence of a user-specified sort parameter, is used as the default 318ea272257SMauro Carvalho Chehab sort field. 319ea272257SMauro Carvalho Chehab 320ea272257SMauro Carvalho Chehab The value 'hitcount' can be used in place of an explicit value in 321ea272257SMauro Carvalho Chehab the 'values' parameter if you don't really need to have any 322ea272257SMauro Carvalho Chehab particular field summed and are mainly interested in hit 323ea272257SMauro Carvalho Chehab frequencies. 324ea272257SMauro Carvalho Chehab 325ea272257SMauro Carvalho Chehab To turn the hist trigger off, simply call up the trigger in the 326ea272257SMauro Carvalho Chehab command history and re-execute it with a '!' prepended:: 327ea272257SMauro Carvalho Chehab 328ea272257SMauro Carvalho Chehab # echo '!hist:key=call_site:val=bytes_req' > \ 329ea272257SMauro Carvalho Chehab /sys/kernel/debug/tracing/events/kmem/kmalloc/trigger 330ea272257SMauro Carvalho Chehab 331ea272257SMauro Carvalho Chehab Finally, notice that the call_site as displayed in the output above 332ea272257SMauro Carvalho Chehab isn't really very useful. It's an address, but normally addresses 333ea272257SMauro Carvalho Chehab are displayed in hex. To have a numeric field displayed as a hex 334ea272257SMauro Carvalho Chehab value, simply append '.hex' to the field name in the trigger:: 335ea272257SMauro Carvalho Chehab 336ea272257SMauro Carvalho Chehab # echo 'hist:key=call_site.hex:val=bytes_req' > \ 337ea272257SMauro Carvalho Chehab /sys/kernel/debug/tracing/events/kmem/kmalloc/trigger 338ea272257SMauro Carvalho Chehab 339ea272257SMauro Carvalho Chehab # cat /sys/kernel/debug/tracing/events/kmem/kmalloc/hist 340ea272257SMauro Carvalho Chehab # trigger info: hist:keys=call_site.hex:vals=bytes_req:sort=hitcount:size=2048 [active] 341ea272257SMauro Carvalho Chehab 342ea272257SMauro Carvalho Chehab { call_site: ffffffffa026b291 } hitcount: 1 bytes_req: 433 343ea272257SMauro Carvalho Chehab { call_site: ffffffffa07186ff } hitcount: 1 bytes_req: 176 344ea272257SMauro Carvalho Chehab { call_site: ffffffff811ae721 } hitcount: 1 bytes_req: 16384 345ea272257SMauro Carvalho Chehab { call_site: ffffffff811c5134 } hitcount: 1 bytes_req: 8 346ea272257SMauro Carvalho Chehab { call_site: ffffffffa04a9ebb } hitcount: 1 bytes_req: 511 347ea272257SMauro Carvalho Chehab { call_site: ffffffff8122e0a6 } hitcount: 1 bytes_req: 12 348ea272257SMauro Carvalho Chehab { call_site: ffffffff8107da84 } hitcount: 1 bytes_req: 152 349ea272257SMauro Carvalho Chehab { call_site: ffffffff812d8246 } hitcount: 1 bytes_req: 24 350ea272257SMauro Carvalho Chehab { call_site: ffffffff811dc1e5 } hitcount: 3 bytes_req: 144 351ea272257SMauro Carvalho Chehab { call_site: ffffffffa02515e8 } hitcount: 3 bytes_req: 648 352ea272257SMauro Carvalho Chehab { call_site: ffffffff81258159 } hitcount: 3 bytes_req: 144 353ea272257SMauro Carvalho Chehab { call_site: ffffffff811c80f4 } hitcount: 4 bytes_req: 544 354ea272257SMauro Carvalho Chehab . 355ea272257SMauro Carvalho Chehab . 356ea272257SMauro Carvalho Chehab . 357ea272257SMauro Carvalho Chehab { call_site: ffffffffa06c7646 } hitcount: 106 bytes_req: 8024 358ea272257SMauro Carvalho Chehab { call_site: ffffffffa06cb246 } hitcount: 132 bytes_req: 31680 359ea272257SMauro Carvalho Chehab { call_site: ffffffffa06cef7a } hitcount: 132 bytes_req: 2112 360ea272257SMauro Carvalho Chehab { call_site: ffffffff8137e399 } hitcount: 132 bytes_req: 23232 361ea272257SMauro Carvalho Chehab { call_site: ffffffffa06c941c } hitcount: 185 bytes_req: 171360 362ea272257SMauro Carvalho Chehab { call_site: ffffffffa06f2a66 } hitcount: 185 bytes_req: 26640 363ea272257SMauro Carvalho Chehab { call_site: ffffffffa036a70e } hitcount: 265 bytes_req: 10600 364ea272257SMauro Carvalho Chehab { call_site: ffffffff81325447 } hitcount: 292 bytes_req: 584 365ea272257SMauro Carvalho Chehab { call_site: ffffffffa072da3c } hitcount: 446 bytes_req: 60656 366ea272257SMauro Carvalho Chehab { call_site: ffffffffa036b1f2 } hitcount: 526 bytes_req: 29456 367ea272257SMauro Carvalho Chehab { call_site: ffffffffa0099c06 } hitcount: 1780 bytes_req: 35600 368ea272257SMauro Carvalho Chehab 369ea272257SMauro Carvalho Chehab Totals: 370ea272257SMauro Carvalho Chehab Hits: 4775 371ea272257SMauro Carvalho Chehab Entries: 46 372ea272257SMauro Carvalho Chehab Dropped: 0 373ea272257SMauro Carvalho Chehab 374ea272257SMauro Carvalho Chehab Even that's only marginally more useful - while hex values do look 375ea272257SMauro Carvalho Chehab more like addresses, what users are typically more interested in 376ea272257SMauro Carvalho Chehab when looking at text addresses are the corresponding symbols 377ea272257SMauro Carvalho Chehab instead. To have an address displayed as symbolic value instead, 378ea272257SMauro Carvalho Chehab simply append '.sym' or '.sym-offset' to the field name in the 379ea272257SMauro Carvalho Chehab trigger:: 380ea272257SMauro Carvalho Chehab 381ea272257SMauro Carvalho Chehab # echo 'hist:key=call_site.sym:val=bytes_req' > \ 382ea272257SMauro Carvalho Chehab /sys/kernel/debug/tracing/events/kmem/kmalloc/trigger 383ea272257SMauro Carvalho Chehab 384ea272257SMauro Carvalho Chehab # cat /sys/kernel/debug/tracing/events/kmem/kmalloc/hist 385ea272257SMauro Carvalho Chehab # trigger info: hist:keys=call_site.sym:vals=bytes_req:sort=hitcount:size=2048 [active] 386ea272257SMauro Carvalho Chehab 387ea272257SMauro Carvalho Chehab { call_site: [ffffffff810adcb9] syslog_print_all } hitcount: 1 bytes_req: 1024 388ea272257SMauro Carvalho Chehab { call_site: [ffffffff8154bc62] usb_control_msg } hitcount: 1 bytes_req: 8 389ea272257SMauro Carvalho Chehab { call_site: [ffffffffa00bf6fe] hidraw_send_report [hid] } hitcount: 1 bytes_req: 7 390ea272257SMauro Carvalho Chehab { call_site: [ffffffff8154acbe] usb_alloc_urb } hitcount: 1 bytes_req: 192 391ea272257SMauro Carvalho Chehab { call_site: [ffffffffa00bf1ca] hidraw_report_event [hid] } hitcount: 1 bytes_req: 7 392ea272257SMauro Carvalho Chehab { call_site: [ffffffff811e3a25] __seq_open_private } hitcount: 1 bytes_req: 40 393ea272257SMauro Carvalho Chehab { call_site: [ffffffff8109524a] alloc_fair_sched_group } hitcount: 2 bytes_req: 128 394ea272257SMauro Carvalho Chehab { call_site: [ffffffff811febd5] fsnotify_alloc_group } hitcount: 2 bytes_req: 528 395ea272257SMauro Carvalho Chehab { call_site: [ffffffff81440f58] __tty_buffer_request_room } hitcount: 2 bytes_req: 2624 396ea272257SMauro Carvalho Chehab { call_site: [ffffffff81200ba6] inotify_new_group } hitcount: 2 bytes_req: 96 397ea272257SMauro Carvalho Chehab { call_site: [ffffffffa05e19af] ieee80211_start_tx_ba_session [mac80211] } hitcount: 2 bytes_req: 464 398ea272257SMauro Carvalho Chehab { call_site: [ffffffff81672406] tcp_get_metrics } hitcount: 2 bytes_req: 304 399ea272257SMauro Carvalho Chehab { call_site: [ffffffff81097ec2] alloc_rt_sched_group } hitcount: 2 bytes_req: 128 400ea272257SMauro Carvalho Chehab { call_site: [ffffffff81089b05] sched_create_group } hitcount: 2 bytes_req: 1424 401ea272257SMauro Carvalho Chehab . 402ea272257SMauro Carvalho Chehab . 403ea272257SMauro Carvalho Chehab . 404ea272257SMauro Carvalho Chehab { call_site: [ffffffffa04a580c] intel_crtc_page_flip [i915] } hitcount: 1185 bytes_req: 123240 405ea272257SMauro Carvalho Chehab { call_site: [ffffffffa0287592] drm_mode_page_flip_ioctl [drm] } hitcount: 1185 bytes_req: 104280 406ea272257SMauro Carvalho Chehab { call_site: [ffffffffa04c4a3c] intel_plane_duplicate_state [i915] } hitcount: 1402 bytes_req: 190672 407ea272257SMauro Carvalho Chehab { call_site: [ffffffff812891ca] ext4_find_extent } hitcount: 1518 bytes_req: 146208 408ea272257SMauro Carvalho Chehab { call_site: [ffffffffa029070e] drm_vma_node_allow [drm] } hitcount: 1746 bytes_req: 69840 409ea272257SMauro Carvalho Chehab { call_site: [ffffffffa045e7c4] i915_gem_do_execbuffer.isra.23 [i915] } hitcount: 2021 bytes_req: 792312 410ea272257SMauro Carvalho Chehab { call_site: [ffffffffa02911f2] drm_modeset_lock_crtc [drm] } hitcount: 2592 bytes_req: 145152 411ea272257SMauro Carvalho Chehab { call_site: [ffffffffa0489a66] intel_ring_begin [i915] } hitcount: 2629 bytes_req: 378576 412ea272257SMauro Carvalho Chehab { call_site: [ffffffffa046041c] i915_gem_execbuffer2 [i915] } hitcount: 2629 bytes_req: 3783248 413ea272257SMauro Carvalho Chehab { call_site: [ffffffff81325607] apparmor_file_alloc_security } hitcount: 5192 bytes_req: 10384 414ea272257SMauro Carvalho Chehab { call_site: [ffffffffa00b7c06] hid_report_raw_event [hid] } hitcount: 5529 bytes_req: 110584 415ea272257SMauro Carvalho Chehab { call_site: [ffffffff8131ebf7] aa_alloc_task_context } hitcount: 21943 bytes_req: 702176 416ea272257SMauro Carvalho Chehab { call_site: [ffffffff8125847d] ext4_htree_store_dirent } hitcount: 55759 bytes_req: 5074265 417ea272257SMauro Carvalho Chehab 418ea272257SMauro Carvalho Chehab Totals: 419ea272257SMauro Carvalho Chehab Hits: 109928 420ea272257SMauro Carvalho Chehab Entries: 71 421ea272257SMauro Carvalho Chehab Dropped: 0 422ea272257SMauro Carvalho Chehab 423ea272257SMauro Carvalho Chehab Because the default sort key above is 'hitcount', the above shows a 424ea272257SMauro Carvalho Chehab the list of call_sites by increasing hitcount, so that at the bottom 425ea272257SMauro Carvalho Chehab we see the functions that made the most kmalloc calls during the 426ea272257SMauro Carvalho Chehab run. If instead we we wanted to see the top kmalloc callers in 427ea272257SMauro Carvalho Chehab terms of the number of bytes requested rather than the number of 428ea272257SMauro Carvalho Chehab calls, and we wanted the top caller to appear at the top, we can use 429ea272257SMauro Carvalho Chehab the 'sort' parameter, along with the 'descending' modifier:: 430ea272257SMauro Carvalho Chehab 431ea272257SMauro Carvalho Chehab # echo 'hist:key=call_site.sym:val=bytes_req:sort=bytes_req.descending' > \ 432ea272257SMauro Carvalho Chehab /sys/kernel/debug/tracing/events/kmem/kmalloc/trigger 433ea272257SMauro Carvalho Chehab 434ea272257SMauro Carvalho Chehab # cat /sys/kernel/debug/tracing/events/kmem/kmalloc/hist 435ea272257SMauro Carvalho Chehab # trigger info: hist:keys=call_site.sym:vals=bytes_req:sort=bytes_req.descending:size=2048 [active] 436ea272257SMauro Carvalho Chehab 437ea272257SMauro Carvalho Chehab { call_site: [ffffffffa046041c] i915_gem_execbuffer2 [i915] } hitcount: 2186 bytes_req: 3397464 438ea272257SMauro Carvalho Chehab { call_site: [ffffffffa045e7c4] i915_gem_do_execbuffer.isra.23 [i915] } hitcount: 1790 bytes_req: 712176 439ea272257SMauro Carvalho Chehab { call_site: [ffffffff8125847d] ext4_htree_store_dirent } hitcount: 8132 bytes_req: 513135 440ea272257SMauro Carvalho Chehab { call_site: [ffffffff811e2a1b] seq_buf_alloc } hitcount: 106 bytes_req: 440128 441ea272257SMauro Carvalho Chehab { call_site: [ffffffffa0489a66] intel_ring_begin [i915] } hitcount: 2186 bytes_req: 314784 442ea272257SMauro Carvalho Chehab { call_site: [ffffffff812891ca] ext4_find_extent } hitcount: 2174 bytes_req: 208992 443ea272257SMauro Carvalho Chehab { call_site: [ffffffff811ae8e1] __kmalloc } hitcount: 8 bytes_req: 131072 444ea272257SMauro Carvalho Chehab { call_site: [ffffffffa04c4a3c] intel_plane_duplicate_state [i915] } hitcount: 859 bytes_req: 116824 445ea272257SMauro Carvalho Chehab { call_site: [ffffffffa02911f2] drm_modeset_lock_crtc [drm] } hitcount: 1834 bytes_req: 102704 446ea272257SMauro Carvalho Chehab { call_site: [ffffffffa04a580c] intel_crtc_page_flip [i915] } hitcount: 972 bytes_req: 101088 447ea272257SMauro Carvalho Chehab { call_site: [ffffffffa0287592] drm_mode_page_flip_ioctl [drm] } hitcount: 972 bytes_req: 85536 448ea272257SMauro Carvalho Chehab { call_site: [ffffffffa00b7c06] hid_report_raw_event [hid] } hitcount: 3333 bytes_req: 66664 449ea272257SMauro Carvalho Chehab { call_site: [ffffffff8137e559] sg_kmalloc } hitcount: 209 bytes_req: 61632 450ea272257SMauro Carvalho Chehab . 451ea272257SMauro Carvalho Chehab . 452ea272257SMauro Carvalho Chehab . 453ea272257SMauro Carvalho Chehab { call_site: [ffffffff81095225] alloc_fair_sched_group } hitcount: 2 bytes_req: 128 454ea272257SMauro Carvalho Chehab { call_site: [ffffffff81097ec2] alloc_rt_sched_group } hitcount: 2 bytes_req: 128 455ea272257SMauro Carvalho Chehab { call_site: [ffffffff812d8406] copy_semundo } hitcount: 2 bytes_req: 48 456ea272257SMauro Carvalho Chehab { call_site: [ffffffff81200ba6] inotify_new_group } hitcount: 1 bytes_req: 48 457ea272257SMauro Carvalho Chehab { call_site: [ffffffffa027121a] drm_getmagic [drm] } hitcount: 1 bytes_req: 48 458ea272257SMauro Carvalho Chehab { call_site: [ffffffff811e3a25] __seq_open_private } hitcount: 1 bytes_req: 40 459ea272257SMauro Carvalho Chehab { call_site: [ffffffff811c52f4] bprm_change_interp } hitcount: 2 bytes_req: 16 460ea272257SMauro Carvalho Chehab { call_site: [ffffffff8154bc62] usb_control_msg } hitcount: 1 bytes_req: 8 461ea272257SMauro Carvalho Chehab { call_site: [ffffffffa00bf1ca] hidraw_report_event [hid] } hitcount: 1 bytes_req: 7 462ea272257SMauro Carvalho Chehab { call_site: [ffffffffa00bf6fe] hidraw_send_report [hid] } hitcount: 1 bytes_req: 7 463ea272257SMauro Carvalho Chehab 464ea272257SMauro Carvalho Chehab Totals: 465ea272257SMauro Carvalho Chehab Hits: 32133 466ea272257SMauro Carvalho Chehab Entries: 81 467ea272257SMauro Carvalho Chehab Dropped: 0 468ea272257SMauro Carvalho Chehab 469ea272257SMauro Carvalho Chehab To display the offset and size information in addition to the symbol 470ea272257SMauro Carvalho Chehab name, just use 'sym-offset' instead:: 471ea272257SMauro Carvalho Chehab 472ea272257SMauro Carvalho Chehab # echo 'hist:key=call_site.sym-offset:val=bytes_req:sort=bytes_req.descending' > \ 473ea272257SMauro Carvalho Chehab /sys/kernel/debug/tracing/events/kmem/kmalloc/trigger 474ea272257SMauro Carvalho Chehab 475ea272257SMauro Carvalho Chehab # cat /sys/kernel/debug/tracing/events/kmem/kmalloc/hist 476ea272257SMauro Carvalho Chehab # trigger info: hist:keys=call_site.sym-offset:vals=bytes_req:sort=bytes_req.descending:size=2048 [active] 477ea272257SMauro Carvalho Chehab 478ea272257SMauro Carvalho Chehab { call_site: [ffffffffa046041c] i915_gem_execbuffer2+0x6c/0x2c0 [i915] } hitcount: 4569 bytes_req: 3163720 479ea272257SMauro Carvalho Chehab { call_site: [ffffffffa0489a66] intel_ring_begin+0xc6/0x1f0 [i915] } hitcount: 4569 bytes_req: 657936 480ea272257SMauro Carvalho Chehab { call_site: [ffffffffa045e7c4] i915_gem_do_execbuffer.isra.23+0x694/0x1020 [i915] } hitcount: 1519 bytes_req: 472936 481ea272257SMauro Carvalho Chehab { call_site: [ffffffffa045e646] i915_gem_do_execbuffer.isra.23+0x516/0x1020 [i915] } hitcount: 3050 bytes_req: 211832 482ea272257SMauro Carvalho Chehab { call_site: [ffffffff811e2a1b] seq_buf_alloc+0x1b/0x50 } hitcount: 34 bytes_req: 148384 483ea272257SMauro Carvalho Chehab { call_site: [ffffffffa04a580c] intel_crtc_page_flip+0xbc/0x870 [i915] } hitcount: 1385 bytes_req: 144040 484ea272257SMauro Carvalho Chehab { call_site: [ffffffff811ae8e1] __kmalloc+0x191/0x1b0 } hitcount: 8 bytes_req: 131072 485ea272257SMauro Carvalho Chehab { call_site: [ffffffffa0287592] drm_mode_page_flip_ioctl+0x282/0x360 [drm] } hitcount: 1385 bytes_req: 121880 486ea272257SMauro Carvalho Chehab { call_site: [ffffffffa02911f2] drm_modeset_lock_crtc+0x32/0x100 [drm] } hitcount: 1848 bytes_req: 103488 487ea272257SMauro Carvalho Chehab { call_site: [ffffffffa04c4a3c] intel_plane_duplicate_state+0x2c/0xa0 [i915] } hitcount: 461 bytes_req: 62696 488ea272257SMauro Carvalho Chehab { call_site: [ffffffffa029070e] drm_vma_node_allow+0x2e/0xd0 [drm] } hitcount: 1541 bytes_req: 61640 489ea272257SMauro Carvalho Chehab { call_site: [ffffffff815f8d7b] sk_prot_alloc+0xcb/0x1b0 } hitcount: 57 bytes_req: 57456 490ea272257SMauro Carvalho Chehab . 491ea272257SMauro Carvalho Chehab . 492ea272257SMauro Carvalho Chehab . 493ea272257SMauro Carvalho Chehab { call_site: [ffffffff8109524a] alloc_fair_sched_group+0x5a/0x1a0 } hitcount: 2 bytes_req: 128 494ea272257SMauro Carvalho Chehab { call_site: [ffffffffa027b921] drm_vm_open_locked+0x31/0xa0 [drm] } hitcount: 3 bytes_req: 96 495ea272257SMauro Carvalho Chehab { call_site: [ffffffff8122e266] proc_self_follow_link+0x76/0xb0 } hitcount: 8 bytes_req: 96 496ea272257SMauro Carvalho Chehab { call_site: [ffffffff81213e80] load_elf_binary+0x240/0x1650 } hitcount: 3 bytes_req: 84 497ea272257SMauro Carvalho Chehab { call_site: [ffffffff8154bc62] usb_control_msg+0x42/0x110 } hitcount: 1 bytes_req: 8 498ea272257SMauro Carvalho Chehab { call_site: [ffffffffa00bf6fe] hidraw_send_report+0x7e/0x1a0 [hid] } hitcount: 1 bytes_req: 7 499ea272257SMauro Carvalho Chehab { call_site: [ffffffffa00bf1ca] hidraw_report_event+0x8a/0x120 [hid] } hitcount: 1 bytes_req: 7 500ea272257SMauro Carvalho Chehab 501ea272257SMauro Carvalho Chehab Totals: 502ea272257SMauro Carvalho Chehab Hits: 26098 503ea272257SMauro Carvalho Chehab Entries: 64 504ea272257SMauro Carvalho Chehab Dropped: 0 505ea272257SMauro Carvalho Chehab 506ea272257SMauro Carvalho Chehab We can also add multiple fields to the 'values' parameter. For 507ea272257SMauro Carvalho Chehab example, we might want to see the total number of bytes allocated 508ea272257SMauro Carvalho Chehab alongside bytes requested, and display the result sorted by bytes 509ea272257SMauro Carvalho Chehab allocated in a descending order:: 510ea272257SMauro Carvalho Chehab 511ea272257SMauro Carvalho Chehab # echo 'hist:keys=call_site.sym:values=bytes_req,bytes_alloc:sort=bytes_alloc.descending' > \ 512ea272257SMauro Carvalho Chehab /sys/kernel/debug/tracing/events/kmem/kmalloc/trigger 513ea272257SMauro Carvalho Chehab 514ea272257SMauro Carvalho Chehab # cat /sys/kernel/debug/tracing/events/kmem/kmalloc/hist 515ea272257SMauro Carvalho Chehab # trigger info: hist:keys=call_site.sym:vals=bytes_req,bytes_alloc:sort=bytes_alloc.descending:size=2048 [active] 516ea272257SMauro Carvalho Chehab 517ea272257SMauro Carvalho Chehab { call_site: [ffffffffa046041c] i915_gem_execbuffer2 [i915] } hitcount: 7403 bytes_req: 4084360 bytes_alloc: 5958016 518ea272257SMauro Carvalho Chehab { call_site: [ffffffff811e2a1b] seq_buf_alloc } hitcount: 541 bytes_req: 2213968 bytes_alloc: 2228224 519ea272257SMauro Carvalho Chehab { call_site: [ffffffffa0489a66] intel_ring_begin [i915] } hitcount: 7404 bytes_req: 1066176 bytes_alloc: 1421568 520ea272257SMauro Carvalho Chehab { call_site: [ffffffffa045e7c4] i915_gem_do_execbuffer.isra.23 [i915] } hitcount: 1565 bytes_req: 557368 bytes_alloc: 1037760 521ea272257SMauro Carvalho Chehab { call_site: [ffffffff8125847d] ext4_htree_store_dirent } hitcount: 9557 bytes_req: 595778 bytes_alloc: 695744 522ea272257SMauro Carvalho Chehab { call_site: [ffffffffa045e646] i915_gem_do_execbuffer.isra.23 [i915] } hitcount: 5839 bytes_req: 430680 bytes_alloc: 470400 523ea272257SMauro Carvalho Chehab { call_site: [ffffffffa04c4a3c] intel_plane_duplicate_state [i915] } hitcount: 2388 bytes_req: 324768 bytes_alloc: 458496 524ea272257SMauro Carvalho Chehab { call_site: [ffffffffa02911f2] drm_modeset_lock_crtc [drm] } hitcount: 3911 bytes_req: 219016 bytes_alloc: 250304 525ea272257SMauro Carvalho Chehab { call_site: [ffffffff815f8d7b] sk_prot_alloc } hitcount: 235 bytes_req: 236880 bytes_alloc: 240640 526ea272257SMauro Carvalho Chehab { call_site: [ffffffff8137e559] sg_kmalloc } hitcount: 557 bytes_req: 169024 bytes_alloc: 221760 527ea272257SMauro Carvalho Chehab { call_site: [ffffffffa00b7c06] hid_report_raw_event [hid] } hitcount: 9378 bytes_req: 187548 bytes_alloc: 206312 528ea272257SMauro Carvalho Chehab { call_site: [ffffffffa04a580c] intel_crtc_page_flip [i915] } hitcount: 1519 bytes_req: 157976 bytes_alloc: 194432 529ea272257SMauro Carvalho Chehab . 530ea272257SMauro Carvalho Chehab . 531ea272257SMauro Carvalho Chehab . 532ea272257SMauro Carvalho Chehab { call_site: [ffffffff8109bd3b] sched_autogroup_create_attach } hitcount: 2 bytes_req: 144 bytes_alloc: 192 533ea272257SMauro Carvalho Chehab { call_site: [ffffffff81097ee8] alloc_rt_sched_group } hitcount: 2 bytes_req: 128 bytes_alloc: 128 534ea272257SMauro Carvalho Chehab { call_site: [ffffffff8109524a] alloc_fair_sched_group } hitcount: 2 bytes_req: 128 bytes_alloc: 128 535ea272257SMauro Carvalho Chehab { call_site: [ffffffff81095225] alloc_fair_sched_group } hitcount: 2 bytes_req: 128 bytes_alloc: 128 536ea272257SMauro Carvalho Chehab { call_site: [ffffffff81097ec2] alloc_rt_sched_group } hitcount: 2 bytes_req: 128 bytes_alloc: 128 537ea272257SMauro Carvalho Chehab { call_site: [ffffffff81213e80] load_elf_binary } hitcount: 3 bytes_req: 84 bytes_alloc: 96 538ea272257SMauro Carvalho Chehab { call_site: [ffffffff81079a2e] kthread_create_on_node } hitcount: 1 bytes_req: 56 bytes_alloc: 64 539ea272257SMauro Carvalho Chehab { call_site: [ffffffffa00bf6fe] hidraw_send_report [hid] } hitcount: 1 bytes_req: 7 bytes_alloc: 8 540ea272257SMauro Carvalho Chehab { call_site: [ffffffff8154bc62] usb_control_msg } hitcount: 1 bytes_req: 8 bytes_alloc: 8 541ea272257SMauro Carvalho Chehab { call_site: [ffffffffa00bf1ca] hidraw_report_event [hid] } hitcount: 1 bytes_req: 7 bytes_alloc: 8 542ea272257SMauro Carvalho Chehab 543ea272257SMauro Carvalho Chehab Totals: 544ea272257SMauro Carvalho Chehab Hits: 66598 545ea272257SMauro Carvalho Chehab Entries: 65 546ea272257SMauro Carvalho Chehab Dropped: 0 547ea272257SMauro Carvalho Chehab 548ea272257SMauro Carvalho Chehab Finally, to finish off our kmalloc example, instead of simply having 549ea272257SMauro Carvalho Chehab the hist trigger display symbolic call_sites, we can have the hist 550ea272257SMauro Carvalho Chehab trigger additionally display the complete set of kernel stack traces 551ea272257SMauro Carvalho Chehab that led to each call_site. To do that, we simply use the special 552ea272257SMauro Carvalho Chehab value 'stacktrace' for the key parameter:: 553ea272257SMauro Carvalho Chehab 554ea272257SMauro Carvalho Chehab # echo 'hist:keys=stacktrace:values=bytes_req,bytes_alloc:sort=bytes_alloc' > \ 555ea272257SMauro Carvalho Chehab /sys/kernel/debug/tracing/events/kmem/kmalloc/trigger 556ea272257SMauro Carvalho Chehab 557ea272257SMauro Carvalho Chehab The above trigger will use the kernel stack trace in effect when an 558ea272257SMauro Carvalho Chehab event is triggered as the key for the hash table. This allows the 559ea272257SMauro Carvalho Chehab enumeration of every kernel callpath that led up to a particular 560ea272257SMauro Carvalho Chehab event, along with a running total of any of the event fields for 561ea272257SMauro Carvalho Chehab that event. Here we tally bytes requested and bytes allocated for 562ea272257SMauro Carvalho Chehab every callpath in the system that led up to a kmalloc (in this case 563ea272257SMauro Carvalho Chehab every callpath to a kmalloc for a kernel compile):: 564ea272257SMauro Carvalho Chehab 565ea272257SMauro Carvalho Chehab # cat /sys/kernel/debug/tracing/events/kmem/kmalloc/hist 566ea272257SMauro Carvalho Chehab # trigger info: hist:keys=stacktrace:vals=bytes_req,bytes_alloc:sort=bytes_alloc:size=2048 [active] 567ea272257SMauro Carvalho Chehab 568ea272257SMauro Carvalho Chehab { stacktrace: 569ea272257SMauro Carvalho Chehab __kmalloc_track_caller+0x10b/0x1a0 570ea272257SMauro Carvalho Chehab kmemdup+0x20/0x50 571ea272257SMauro Carvalho Chehab hidraw_report_event+0x8a/0x120 [hid] 572ea272257SMauro Carvalho Chehab hid_report_raw_event+0x3ea/0x440 [hid] 573ea272257SMauro Carvalho Chehab hid_input_report+0x112/0x190 [hid] 574ea272257SMauro Carvalho Chehab hid_irq_in+0xc2/0x260 [usbhid] 575ea272257SMauro Carvalho Chehab __usb_hcd_giveback_urb+0x72/0x120 576ea272257SMauro Carvalho Chehab usb_giveback_urb_bh+0x9e/0xe0 577ea272257SMauro Carvalho Chehab tasklet_hi_action+0xf8/0x100 578ea272257SMauro Carvalho Chehab __do_softirq+0x114/0x2c0 579ea272257SMauro Carvalho Chehab irq_exit+0xa5/0xb0 580ea272257SMauro Carvalho Chehab do_IRQ+0x5a/0xf0 581ea272257SMauro Carvalho Chehab ret_from_intr+0x0/0x30 582ea272257SMauro Carvalho Chehab cpuidle_enter+0x17/0x20 583ea272257SMauro Carvalho Chehab cpu_startup_entry+0x315/0x3e0 584ea272257SMauro Carvalho Chehab rest_init+0x7c/0x80 585ea272257SMauro Carvalho Chehab } hitcount: 3 bytes_req: 21 bytes_alloc: 24 586ea272257SMauro Carvalho Chehab { stacktrace: 587ea272257SMauro Carvalho Chehab __kmalloc_track_caller+0x10b/0x1a0 588ea272257SMauro Carvalho Chehab kmemdup+0x20/0x50 589ea272257SMauro Carvalho Chehab hidraw_report_event+0x8a/0x120 [hid] 590ea272257SMauro Carvalho Chehab hid_report_raw_event+0x3ea/0x440 [hid] 591ea272257SMauro Carvalho Chehab hid_input_report+0x112/0x190 [hid] 592ea272257SMauro Carvalho Chehab hid_irq_in+0xc2/0x260 [usbhid] 593ea272257SMauro Carvalho Chehab __usb_hcd_giveback_urb+0x72/0x120 594ea272257SMauro Carvalho Chehab usb_giveback_urb_bh+0x9e/0xe0 595ea272257SMauro Carvalho Chehab tasklet_hi_action+0xf8/0x100 596ea272257SMauro Carvalho Chehab __do_softirq+0x114/0x2c0 597ea272257SMauro Carvalho Chehab irq_exit+0xa5/0xb0 598ea272257SMauro Carvalho Chehab do_IRQ+0x5a/0xf0 599ea272257SMauro Carvalho Chehab ret_from_intr+0x0/0x30 600ea272257SMauro Carvalho Chehab } hitcount: 3 bytes_req: 21 bytes_alloc: 24 601ea272257SMauro Carvalho Chehab { stacktrace: 602ea272257SMauro Carvalho Chehab kmem_cache_alloc_trace+0xeb/0x150 603ea272257SMauro Carvalho Chehab aa_alloc_task_context+0x27/0x40 604ea272257SMauro Carvalho Chehab apparmor_cred_prepare+0x1f/0x50 605ea272257SMauro Carvalho Chehab security_prepare_creds+0x16/0x20 606ea272257SMauro Carvalho Chehab prepare_creds+0xdf/0x1a0 607ea272257SMauro Carvalho Chehab SyS_capset+0xb5/0x200 608ea272257SMauro Carvalho Chehab system_call_fastpath+0x12/0x6a 609ea272257SMauro Carvalho Chehab } hitcount: 1 bytes_req: 32 bytes_alloc: 32 610ea272257SMauro Carvalho Chehab . 611ea272257SMauro Carvalho Chehab . 612ea272257SMauro Carvalho Chehab . 613ea272257SMauro Carvalho Chehab { stacktrace: 614ea272257SMauro Carvalho Chehab __kmalloc+0x11b/0x1b0 615ea272257SMauro Carvalho Chehab i915_gem_execbuffer2+0x6c/0x2c0 [i915] 616ea272257SMauro Carvalho Chehab drm_ioctl+0x349/0x670 [drm] 617ea272257SMauro Carvalho Chehab do_vfs_ioctl+0x2f0/0x4f0 618ea272257SMauro Carvalho Chehab SyS_ioctl+0x81/0xa0 619ea272257SMauro Carvalho Chehab system_call_fastpath+0x12/0x6a 620ea272257SMauro Carvalho Chehab } hitcount: 17726 bytes_req: 13944120 bytes_alloc: 19593808 621ea272257SMauro Carvalho Chehab { stacktrace: 622ea272257SMauro Carvalho Chehab __kmalloc+0x11b/0x1b0 623ea272257SMauro Carvalho Chehab load_elf_phdrs+0x76/0xa0 624ea272257SMauro Carvalho Chehab load_elf_binary+0x102/0x1650 625ea272257SMauro Carvalho Chehab search_binary_handler+0x97/0x1d0 626ea272257SMauro Carvalho Chehab do_execveat_common.isra.34+0x551/0x6e0 627ea272257SMauro Carvalho Chehab SyS_execve+0x3a/0x50 628ea272257SMauro Carvalho Chehab return_from_execve+0x0/0x23 629ea272257SMauro Carvalho Chehab } hitcount: 33348 bytes_req: 17152128 bytes_alloc: 20226048 630ea272257SMauro Carvalho Chehab { stacktrace: 631ea272257SMauro Carvalho Chehab kmem_cache_alloc_trace+0xeb/0x150 632ea272257SMauro Carvalho Chehab apparmor_file_alloc_security+0x27/0x40 633ea272257SMauro Carvalho Chehab security_file_alloc+0x16/0x20 634ea272257SMauro Carvalho Chehab get_empty_filp+0x93/0x1c0 635ea272257SMauro Carvalho Chehab path_openat+0x31/0x5f0 636ea272257SMauro Carvalho Chehab do_filp_open+0x3a/0x90 637ea272257SMauro Carvalho Chehab do_sys_open+0x128/0x220 638ea272257SMauro Carvalho Chehab SyS_open+0x1e/0x20 639ea272257SMauro Carvalho Chehab system_call_fastpath+0x12/0x6a 640ea272257SMauro Carvalho Chehab } hitcount: 4766422 bytes_req: 9532844 bytes_alloc: 38131376 641ea272257SMauro Carvalho Chehab { stacktrace: 642ea272257SMauro Carvalho Chehab __kmalloc+0x11b/0x1b0 643ea272257SMauro Carvalho Chehab seq_buf_alloc+0x1b/0x50 644ea272257SMauro Carvalho Chehab seq_read+0x2cc/0x370 645ea272257SMauro Carvalho Chehab proc_reg_read+0x3d/0x80 646ea272257SMauro Carvalho Chehab __vfs_read+0x28/0xe0 647ea272257SMauro Carvalho Chehab vfs_read+0x86/0x140 648ea272257SMauro Carvalho Chehab SyS_read+0x46/0xb0 649ea272257SMauro Carvalho Chehab system_call_fastpath+0x12/0x6a 650ea272257SMauro Carvalho Chehab } hitcount: 19133 bytes_req: 78368768 bytes_alloc: 78368768 651ea272257SMauro Carvalho Chehab 652ea272257SMauro Carvalho Chehab Totals: 653ea272257SMauro Carvalho Chehab Hits: 6085872 654ea272257SMauro Carvalho Chehab Entries: 253 655ea272257SMauro Carvalho Chehab Dropped: 0 656ea272257SMauro Carvalho Chehab 657ea272257SMauro Carvalho Chehab If you key a hist trigger on common_pid, in order for example to 658ea272257SMauro Carvalho Chehab gather and display sorted totals for each process, you can use the 659ea272257SMauro Carvalho Chehab special .execname modifier to display the executable names for the 660ea272257SMauro Carvalho Chehab processes in the table rather than raw pids. The example below 661ea272257SMauro Carvalho Chehab keeps a per-process sum of total bytes read:: 662ea272257SMauro Carvalho Chehab 663ea272257SMauro Carvalho Chehab # echo 'hist:key=common_pid.execname:val=count:sort=count.descending' > \ 664ea272257SMauro Carvalho Chehab /sys/kernel/debug/tracing/events/syscalls/sys_enter_read/trigger 665ea272257SMauro Carvalho Chehab 666ea272257SMauro Carvalho Chehab # cat /sys/kernel/debug/tracing/events/syscalls/sys_enter_read/hist 667ea272257SMauro Carvalho Chehab # trigger info: hist:keys=common_pid.execname:vals=count:sort=count.descending:size=2048 [active] 668ea272257SMauro Carvalho Chehab 669ea272257SMauro Carvalho Chehab { common_pid: gnome-terminal [ 3196] } hitcount: 280 count: 1093512 670ea272257SMauro Carvalho Chehab { common_pid: Xorg [ 1309] } hitcount: 525 count: 256640 671ea272257SMauro Carvalho Chehab { common_pid: compiz [ 2889] } hitcount: 59 count: 254400 672ea272257SMauro Carvalho Chehab { common_pid: bash [ 8710] } hitcount: 3 count: 66369 673ea272257SMauro Carvalho Chehab { common_pid: dbus-daemon-lau [ 8703] } hitcount: 49 count: 47739 674ea272257SMauro Carvalho Chehab { common_pid: irqbalance [ 1252] } hitcount: 27 count: 27648 675ea272257SMauro Carvalho Chehab { common_pid: 01ifupdown [ 8705] } hitcount: 3 count: 17216 676ea272257SMauro Carvalho Chehab { common_pid: dbus-daemon [ 772] } hitcount: 10 count: 12396 677ea272257SMauro Carvalho Chehab { common_pid: Socket Thread [ 8342] } hitcount: 11 count: 11264 678ea272257SMauro Carvalho Chehab { common_pid: nm-dhcp-client. [ 8701] } hitcount: 6 count: 7424 679ea272257SMauro Carvalho Chehab { common_pid: gmain [ 1315] } hitcount: 18 count: 6336 680ea272257SMauro Carvalho Chehab . 681ea272257SMauro Carvalho Chehab . 682ea272257SMauro Carvalho Chehab . 683ea272257SMauro Carvalho Chehab { common_pid: postgres [ 1892] } hitcount: 2 count: 32 684ea272257SMauro Carvalho Chehab { common_pid: postgres [ 1891] } hitcount: 2 count: 32 685ea272257SMauro Carvalho Chehab { common_pid: gmain [ 8704] } hitcount: 2 count: 32 686ea272257SMauro Carvalho Chehab { common_pid: upstart-dbus-br [ 2740] } hitcount: 21 count: 21 687ea272257SMauro Carvalho Chehab { common_pid: nm-dispatcher.a [ 8696] } hitcount: 1 count: 16 688ea272257SMauro Carvalho Chehab { common_pid: indicator-datet [ 2904] } hitcount: 1 count: 16 689ea272257SMauro Carvalho Chehab { common_pid: gdbus [ 2998] } hitcount: 1 count: 16 690ea272257SMauro Carvalho Chehab { common_pid: rtkit-daemon [ 2052] } hitcount: 1 count: 8 691ea272257SMauro Carvalho Chehab { common_pid: init [ 1] } hitcount: 2 count: 2 692ea272257SMauro Carvalho Chehab 693ea272257SMauro Carvalho Chehab Totals: 694ea272257SMauro Carvalho Chehab Hits: 2116 695ea272257SMauro Carvalho Chehab Entries: 51 696ea272257SMauro Carvalho Chehab Dropped: 0 697ea272257SMauro Carvalho Chehab 698ea272257SMauro Carvalho Chehab Similarly, if you key a hist trigger on syscall id, for example to 699ea272257SMauro Carvalho Chehab gather and display a list of systemwide syscall hits, you can use 700ea272257SMauro Carvalho Chehab the special .syscall modifier to display the syscall names rather 701ea272257SMauro Carvalho Chehab than raw ids. The example below keeps a running total of syscall 702ea272257SMauro Carvalho Chehab counts for the system during the run:: 703ea272257SMauro Carvalho Chehab 704ea272257SMauro Carvalho Chehab # echo 'hist:key=id.syscall:val=hitcount' > \ 705ea272257SMauro Carvalho Chehab /sys/kernel/debug/tracing/events/raw_syscalls/sys_enter/trigger 706ea272257SMauro Carvalho Chehab 707ea272257SMauro Carvalho Chehab # cat /sys/kernel/debug/tracing/events/raw_syscalls/sys_enter/hist 708ea272257SMauro Carvalho Chehab # trigger info: hist:keys=id.syscall:vals=hitcount:sort=hitcount:size=2048 [active] 709ea272257SMauro Carvalho Chehab 710ea272257SMauro Carvalho Chehab { id: sys_fsync [ 74] } hitcount: 1 711ea272257SMauro Carvalho Chehab { id: sys_newuname [ 63] } hitcount: 1 712ea272257SMauro Carvalho Chehab { id: sys_prctl [157] } hitcount: 1 713ea272257SMauro Carvalho Chehab { id: sys_statfs [137] } hitcount: 1 714ea272257SMauro Carvalho Chehab { id: sys_symlink [ 88] } hitcount: 1 715ea272257SMauro Carvalho Chehab { id: sys_sendmmsg [307] } hitcount: 1 716ea272257SMauro Carvalho Chehab { id: sys_semctl [ 66] } hitcount: 1 717ea272257SMauro Carvalho Chehab { id: sys_readlink [ 89] } hitcount: 3 718ea272257SMauro Carvalho Chehab { id: sys_bind [ 49] } hitcount: 3 719ea272257SMauro Carvalho Chehab { id: sys_getsockname [ 51] } hitcount: 3 720ea272257SMauro Carvalho Chehab { id: sys_unlink [ 87] } hitcount: 3 721ea272257SMauro Carvalho Chehab { id: sys_rename [ 82] } hitcount: 4 722ea272257SMauro Carvalho Chehab { id: unknown_syscall [ 58] } hitcount: 4 723ea272257SMauro Carvalho Chehab { id: sys_connect [ 42] } hitcount: 4 724ea272257SMauro Carvalho Chehab { id: sys_getpid [ 39] } hitcount: 4 725ea272257SMauro Carvalho Chehab . 726ea272257SMauro Carvalho Chehab . 727ea272257SMauro Carvalho Chehab . 728ea272257SMauro Carvalho Chehab { id: sys_rt_sigprocmask [ 14] } hitcount: 952 729ea272257SMauro Carvalho Chehab { id: sys_futex [202] } hitcount: 1534 730ea272257SMauro Carvalho Chehab { id: sys_write [ 1] } hitcount: 2689 731ea272257SMauro Carvalho Chehab { id: sys_setitimer [ 38] } hitcount: 2797 732ea272257SMauro Carvalho Chehab { id: sys_read [ 0] } hitcount: 3202 733ea272257SMauro Carvalho Chehab { id: sys_select [ 23] } hitcount: 3773 734ea272257SMauro Carvalho Chehab { id: sys_writev [ 20] } hitcount: 4531 735ea272257SMauro Carvalho Chehab { id: sys_poll [ 7] } hitcount: 8314 736ea272257SMauro Carvalho Chehab { id: sys_recvmsg [ 47] } hitcount: 13738 737ea272257SMauro Carvalho Chehab { id: sys_ioctl [ 16] } hitcount: 21843 738ea272257SMauro Carvalho Chehab 739ea272257SMauro Carvalho Chehab Totals: 740ea272257SMauro Carvalho Chehab Hits: 67612 741ea272257SMauro Carvalho Chehab Entries: 72 742ea272257SMauro Carvalho Chehab Dropped: 0 743ea272257SMauro Carvalho Chehab 744ea272257SMauro Carvalho Chehab The syscall counts above provide a rough overall picture of system 745ea272257SMauro Carvalho Chehab call activity on the system; we can see for example that the most 746ea272257SMauro Carvalho Chehab popular system call on this system was the 'sys_ioctl' system call. 747ea272257SMauro Carvalho Chehab 748ea272257SMauro Carvalho Chehab We can use 'compound' keys to refine that number and provide some 749ea272257SMauro Carvalho Chehab further insight as to which processes exactly contribute to the 750ea272257SMauro Carvalho Chehab overall ioctl count. 751ea272257SMauro Carvalho Chehab 752ea272257SMauro Carvalho Chehab The command below keeps a hitcount for every unique combination of 753ea272257SMauro Carvalho Chehab system call id and pid - the end result is essentially a table 754ea272257SMauro Carvalho Chehab that keeps a per-pid sum of system call hits. The results are 755ea272257SMauro Carvalho Chehab sorted using the system call id as the primary key, and the 756ea272257SMauro Carvalho Chehab hitcount sum as the secondary key:: 757ea272257SMauro Carvalho Chehab 758ea272257SMauro Carvalho Chehab # echo 'hist:key=id.syscall,common_pid.execname:val=hitcount:sort=id,hitcount' > \ 759ea272257SMauro Carvalho Chehab /sys/kernel/debug/tracing/events/raw_syscalls/sys_enter/trigger 760ea272257SMauro Carvalho Chehab 761ea272257SMauro Carvalho Chehab # cat /sys/kernel/debug/tracing/events/raw_syscalls/sys_enter/hist 762ea272257SMauro Carvalho Chehab # trigger info: hist:keys=id.syscall,common_pid.execname:vals=hitcount:sort=id.syscall,hitcount:size=2048 [active] 763ea272257SMauro Carvalho Chehab 764ea272257SMauro Carvalho Chehab { id: sys_read [ 0], common_pid: rtkit-daemon [ 1877] } hitcount: 1 765ea272257SMauro Carvalho Chehab { id: sys_read [ 0], common_pid: gdbus [ 2976] } hitcount: 1 766ea272257SMauro Carvalho Chehab { id: sys_read [ 0], common_pid: console-kit-dae [ 3400] } hitcount: 1 767ea272257SMauro Carvalho Chehab { id: sys_read [ 0], common_pid: postgres [ 1865] } hitcount: 1 768ea272257SMauro Carvalho Chehab { id: sys_read [ 0], common_pid: deja-dup-monito [ 3543] } hitcount: 2 769ea272257SMauro Carvalho Chehab { id: sys_read [ 0], common_pid: NetworkManager [ 890] } hitcount: 2 770ea272257SMauro Carvalho Chehab { id: sys_read [ 0], common_pid: evolution-calen [ 3048] } hitcount: 2 771ea272257SMauro Carvalho Chehab { id: sys_read [ 0], common_pid: postgres [ 1864] } hitcount: 2 772ea272257SMauro Carvalho Chehab { id: sys_read [ 0], common_pid: nm-applet [ 3022] } hitcount: 2 773ea272257SMauro Carvalho Chehab { id: sys_read [ 0], common_pid: whoopsie [ 1212] } hitcount: 2 774ea272257SMauro Carvalho Chehab . 775ea272257SMauro Carvalho Chehab . 776ea272257SMauro Carvalho Chehab . 777ea272257SMauro Carvalho Chehab { id: sys_ioctl [ 16], common_pid: bash [ 8479] } hitcount: 1 778ea272257SMauro Carvalho Chehab { id: sys_ioctl [ 16], common_pid: bash [ 3472] } hitcount: 12 779ea272257SMauro Carvalho Chehab { id: sys_ioctl [ 16], common_pid: gnome-terminal [ 3199] } hitcount: 16 780ea272257SMauro Carvalho Chehab { id: sys_ioctl [ 16], common_pid: Xorg [ 1267] } hitcount: 1808 781ea272257SMauro Carvalho Chehab { id: sys_ioctl [ 16], common_pid: compiz [ 2994] } hitcount: 5580 782ea272257SMauro Carvalho Chehab . 783ea272257SMauro Carvalho Chehab . 784ea272257SMauro Carvalho Chehab . 785ea272257SMauro Carvalho Chehab { id: sys_waitid [247], common_pid: upstart-dbus-br [ 2690] } hitcount: 3 786ea272257SMauro Carvalho Chehab { id: sys_waitid [247], common_pid: upstart-dbus-br [ 2688] } hitcount: 16 787ea272257SMauro Carvalho Chehab { id: sys_inotify_add_watch [254], common_pid: gmain [ 975] } hitcount: 2 788ea272257SMauro Carvalho Chehab { id: sys_inotify_add_watch [254], common_pid: gmain [ 3204] } hitcount: 4 789ea272257SMauro Carvalho Chehab { id: sys_inotify_add_watch [254], common_pid: gmain [ 2888] } hitcount: 4 790ea272257SMauro Carvalho Chehab { id: sys_inotify_add_watch [254], common_pid: gmain [ 3003] } hitcount: 4 791ea272257SMauro Carvalho Chehab { id: sys_inotify_add_watch [254], common_pid: gmain [ 2873] } hitcount: 4 792ea272257SMauro Carvalho Chehab { id: sys_inotify_add_watch [254], common_pid: gmain [ 3196] } hitcount: 6 793ea272257SMauro Carvalho Chehab { id: sys_openat [257], common_pid: java [ 2623] } hitcount: 2 794ea272257SMauro Carvalho Chehab { id: sys_eventfd2 [290], common_pid: ibus-ui-gtk3 [ 2760] } hitcount: 4 795ea272257SMauro Carvalho Chehab { id: sys_eventfd2 [290], common_pid: compiz [ 2994] } hitcount: 6 796ea272257SMauro Carvalho Chehab 797ea272257SMauro Carvalho Chehab Totals: 798ea272257SMauro Carvalho Chehab Hits: 31536 799ea272257SMauro Carvalho Chehab Entries: 323 800ea272257SMauro Carvalho Chehab Dropped: 0 801ea272257SMauro Carvalho Chehab 802ea272257SMauro Carvalho Chehab The above list does give us a breakdown of the ioctl syscall by 803ea272257SMauro Carvalho Chehab pid, but it also gives us quite a bit more than that, which we 804ea272257SMauro Carvalho Chehab don't really care about at the moment. Since we know the syscall 805ea272257SMauro Carvalho Chehab id for sys_ioctl (16, displayed next to the sys_ioctl name), we 806ea272257SMauro Carvalho Chehab can use that to filter out all the other syscalls:: 807ea272257SMauro Carvalho Chehab 808ea272257SMauro Carvalho Chehab # echo 'hist:key=id.syscall,common_pid.execname:val=hitcount:sort=id,hitcount if id == 16' > \ 809ea272257SMauro Carvalho Chehab /sys/kernel/debug/tracing/events/raw_syscalls/sys_enter/trigger 810ea272257SMauro Carvalho Chehab 811ea272257SMauro Carvalho Chehab # cat /sys/kernel/debug/tracing/events/raw_syscalls/sys_enter/hist 812ea272257SMauro Carvalho Chehab # trigger info: hist:keys=id.syscall,common_pid.execname:vals=hitcount:sort=id.syscall,hitcount:size=2048 if id == 16 [active] 813ea272257SMauro Carvalho Chehab 814ea272257SMauro Carvalho Chehab { id: sys_ioctl [ 16], common_pid: gmain [ 2769] } hitcount: 1 815ea272257SMauro Carvalho Chehab { id: sys_ioctl [ 16], common_pid: evolution-addre [ 8571] } hitcount: 1 816ea272257SMauro Carvalho Chehab { id: sys_ioctl [ 16], common_pid: gmain [ 3003] } hitcount: 1 817ea272257SMauro Carvalho Chehab { id: sys_ioctl [ 16], common_pid: gmain [ 2781] } hitcount: 1 818ea272257SMauro Carvalho Chehab { id: sys_ioctl [ 16], common_pid: gmain [ 2829] } hitcount: 1 819ea272257SMauro Carvalho Chehab { id: sys_ioctl [ 16], common_pid: bash [ 8726] } hitcount: 1 820ea272257SMauro Carvalho Chehab { id: sys_ioctl [ 16], common_pid: bash [ 8508] } hitcount: 1 821ea272257SMauro Carvalho Chehab { id: sys_ioctl [ 16], common_pid: gmain [ 2970] } hitcount: 1 822ea272257SMauro Carvalho Chehab { id: sys_ioctl [ 16], common_pid: gmain [ 2768] } hitcount: 1 823ea272257SMauro Carvalho Chehab . 824ea272257SMauro Carvalho Chehab . 825ea272257SMauro Carvalho Chehab . 826ea272257SMauro Carvalho Chehab { id: sys_ioctl [ 16], common_pid: pool [ 8559] } hitcount: 45 827ea272257SMauro Carvalho Chehab { id: sys_ioctl [ 16], common_pid: pool [ 8555] } hitcount: 48 828ea272257SMauro Carvalho Chehab { id: sys_ioctl [ 16], common_pid: pool [ 8551] } hitcount: 48 829ea272257SMauro Carvalho Chehab { id: sys_ioctl [ 16], common_pid: avahi-daemon [ 896] } hitcount: 66 830ea272257SMauro Carvalho Chehab { id: sys_ioctl [ 16], common_pid: Xorg [ 1267] } hitcount: 26674 831ea272257SMauro Carvalho Chehab { id: sys_ioctl [ 16], common_pid: compiz [ 2994] } hitcount: 73443 832ea272257SMauro Carvalho Chehab 833ea272257SMauro Carvalho Chehab Totals: 834ea272257SMauro Carvalho Chehab Hits: 101162 835ea272257SMauro Carvalho Chehab Entries: 103 836ea272257SMauro Carvalho Chehab Dropped: 0 837ea272257SMauro Carvalho Chehab 838ea272257SMauro Carvalho Chehab The above output shows that 'compiz' and 'Xorg' are far and away 839ea272257SMauro Carvalho Chehab the heaviest ioctl callers (which might lead to questions about 840ea272257SMauro Carvalho Chehab whether they really need to be making all those calls and to 841ea272257SMauro Carvalho Chehab possible avenues for further investigation.) 842ea272257SMauro Carvalho Chehab 843ea272257SMauro Carvalho Chehab The compound key examples used a key and a sum value (hitcount) to 844ea272257SMauro Carvalho Chehab sort the output, but we can just as easily use two keys instead. 845ea272257SMauro Carvalho Chehab Here's an example where we use a compound key composed of the the 846ea272257SMauro Carvalho Chehab common_pid and size event fields. Sorting with pid as the primary 847ea272257SMauro Carvalho Chehab key and 'size' as the secondary key allows us to display an 848ea272257SMauro Carvalho Chehab ordered summary of the recvfrom sizes, with counts, received by 849ea272257SMauro Carvalho Chehab each process:: 850ea272257SMauro Carvalho Chehab 851ea272257SMauro Carvalho Chehab # echo 'hist:key=common_pid.execname,size:val=hitcount:sort=common_pid,size' > \ 852ea272257SMauro Carvalho Chehab /sys/kernel/debug/tracing/events/syscalls/sys_enter_recvfrom/trigger 853ea272257SMauro Carvalho Chehab 854ea272257SMauro Carvalho Chehab # cat /sys/kernel/debug/tracing/events/syscalls/sys_enter_recvfrom/hist 855ea272257SMauro Carvalho Chehab # trigger info: hist:keys=common_pid.execname,size:vals=hitcount:sort=common_pid.execname,size:size=2048 [active] 856ea272257SMauro Carvalho Chehab 857ea272257SMauro Carvalho Chehab { common_pid: smbd [ 784], size: 4 } hitcount: 1 858ea272257SMauro Carvalho Chehab { common_pid: dnsmasq [ 1412], size: 4096 } hitcount: 672 859ea272257SMauro Carvalho Chehab { common_pid: postgres [ 1796], size: 1000 } hitcount: 6 860ea272257SMauro Carvalho Chehab { common_pid: postgres [ 1867], size: 1000 } hitcount: 10 861ea272257SMauro Carvalho Chehab { common_pid: bamfdaemon [ 2787], size: 28 } hitcount: 2 862ea272257SMauro Carvalho Chehab { common_pid: bamfdaemon [ 2787], size: 14360 } hitcount: 1 863ea272257SMauro Carvalho Chehab { common_pid: compiz [ 2994], size: 8 } hitcount: 1 864ea272257SMauro Carvalho Chehab { common_pid: compiz [ 2994], size: 20 } hitcount: 11 865ea272257SMauro Carvalho Chehab { common_pid: gnome-terminal [ 3199], size: 4 } hitcount: 2 866ea272257SMauro Carvalho Chehab { common_pid: firefox [ 8817], size: 4 } hitcount: 1 867ea272257SMauro Carvalho Chehab { common_pid: firefox [ 8817], size: 8 } hitcount: 5 868ea272257SMauro Carvalho Chehab { common_pid: firefox [ 8817], size: 588 } hitcount: 2 869ea272257SMauro Carvalho Chehab { common_pid: firefox [ 8817], size: 628 } hitcount: 1 870ea272257SMauro Carvalho Chehab { common_pid: firefox [ 8817], size: 6944 } hitcount: 1 871ea272257SMauro Carvalho Chehab { common_pid: firefox [ 8817], size: 408880 } hitcount: 2 872ea272257SMauro Carvalho Chehab { common_pid: firefox [ 8822], size: 8 } hitcount: 2 873ea272257SMauro Carvalho Chehab { common_pid: firefox [ 8822], size: 160 } hitcount: 2 874ea272257SMauro Carvalho Chehab { common_pid: firefox [ 8822], size: 320 } hitcount: 2 875ea272257SMauro Carvalho Chehab { common_pid: firefox [ 8822], size: 352 } hitcount: 1 876ea272257SMauro Carvalho Chehab . 877ea272257SMauro Carvalho Chehab . 878ea272257SMauro Carvalho Chehab . 879ea272257SMauro Carvalho Chehab { common_pid: pool [ 8923], size: 1960 } hitcount: 10 880ea272257SMauro Carvalho Chehab { common_pid: pool [ 8923], size: 2048 } hitcount: 10 881ea272257SMauro Carvalho Chehab { common_pid: pool [ 8924], size: 1960 } hitcount: 10 882ea272257SMauro Carvalho Chehab { common_pid: pool [ 8924], size: 2048 } hitcount: 10 883ea272257SMauro Carvalho Chehab { common_pid: pool [ 8928], size: 1964 } hitcount: 4 884ea272257SMauro Carvalho Chehab { common_pid: pool [ 8928], size: 1965 } hitcount: 2 885ea272257SMauro Carvalho Chehab { common_pid: pool [ 8928], size: 2048 } hitcount: 6 886ea272257SMauro Carvalho Chehab { common_pid: pool [ 8929], size: 1982 } hitcount: 1 887ea272257SMauro Carvalho Chehab { common_pid: pool [ 8929], size: 2048 } hitcount: 1 888ea272257SMauro Carvalho Chehab 889ea272257SMauro Carvalho Chehab Totals: 890ea272257SMauro Carvalho Chehab Hits: 2016 891ea272257SMauro Carvalho Chehab Entries: 224 892ea272257SMauro Carvalho Chehab Dropped: 0 893ea272257SMauro Carvalho Chehab 894ea272257SMauro Carvalho Chehab The above example also illustrates the fact that although a compound 895ea272257SMauro Carvalho Chehab key is treated as a single entity for hashing purposes, the sub-keys 896ea272257SMauro Carvalho Chehab it's composed of can be accessed independently. 897ea272257SMauro Carvalho Chehab 898ea272257SMauro Carvalho Chehab The next example uses a string field as the hash key and 899ea272257SMauro Carvalho Chehab demonstrates how you can manually pause and continue a hist trigger. 900ea272257SMauro Carvalho Chehab In this example, we'll aggregate fork counts and don't expect a 901ea272257SMauro Carvalho Chehab large number of entries in the hash table, so we'll drop it to a 902ea272257SMauro Carvalho Chehab much smaller number, say 256:: 903ea272257SMauro Carvalho Chehab 904ea272257SMauro Carvalho Chehab # echo 'hist:key=child_comm:val=hitcount:size=256' > \ 905ea272257SMauro Carvalho Chehab /sys/kernel/debug/tracing/events/sched/sched_process_fork/trigger 906ea272257SMauro Carvalho Chehab 907ea272257SMauro Carvalho Chehab # cat /sys/kernel/debug/tracing/events/sched/sched_process_fork/hist 908ea272257SMauro Carvalho Chehab # trigger info: hist:keys=child_comm:vals=hitcount:sort=hitcount:size=256 [active] 909ea272257SMauro Carvalho Chehab 910ea272257SMauro Carvalho Chehab { child_comm: dconf worker } hitcount: 1 911ea272257SMauro Carvalho Chehab { child_comm: ibus-daemon } hitcount: 1 912ea272257SMauro Carvalho Chehab { child_comm: whoopsie } hitcount: 1 913ea272257SMauro Carvalho Chehab { child_comm: smbd } hitcount: 1 914ea272257SMauro Carvalho Chehab { child_comm: gdbus } hitcount: 1 915ea272257SMauro Carvalho Chehab { child_comm: kthreadd } hitcount: 1 916ea272257SMauro Carvalho Chehab { child_comm: dconf worker } hitcount: 1 917ea272257SMauro Carvalho Chehab { child_comm: evolution-alarm } hitcount: 2 918ea272257SMauro Carvalho Chehab { child_comm: Socket Thread } hitcount: 2 919ea272257SMauro Carvalho Chehab { child_comm: postgres } hitcount: 2 920ea272257SMauro Carvalho Chehab { child_comm: bash } hitcount: 3 921ea272257SMauro Carvalho Chehab { child_comm: compiz } hitcount: 3 922ea272257SMauro Carvalho Chehab { child_comm: evolution-sourc } hitcount: 4 923ea272257SMauro Carvalho Chehab { child_comm: dhclient } hitcount: 4 924ea272257SMauro Carvalho Chehab { child_comm: pool } hitcount: 5 925ea272257SMauro Carvalho Chehab { child_comm: nm-dispatcher.a } hitcount: 8 926ea272257SMauro Carvalho Chehab { child_comm: firefox } hitcount: 8 927ea272257SMauro Carvalho Chehab { child_comm: dbus-daemon } hitcount: 8 928ea272257SMauro Carvalho Chehab { child_comm: glib-pacrunner } hitcount: 10 929ea272257SMauro Carvalho Chehab { child_comm: evolution } hitcount: 23 930ea272257SMauro Carvalho Chehab 931ea272257SMauro Carvalho Chehab Totals: 932ea272257SMauro Carvalho Chehab Hits: 89 933ea272257SMauro Carvalho Chehab Entries: 20 934ea272257SMauro Carvalho Chehab Dropped: 0 935ea272257SMauro Carvalho Chehab 936ea272257SMauro Carvalho Chehab If we want to pause the hist trigger, we can simply append :pause to 937ea272257SMauro Carvalho Chehab the command that started the trigger. Notice that the trigger info 938ea272257SMauro Carvalho Chehab displays as [paused]:: 939ea272257SMauro Carvalho Chehab 940ea272257SMauro Carvalho Chehab # echo 'hist:key=child_comm:val=hitcount:size=256:pause' >> \ 941ea272257SMauro Carvalho Chehab /sys/kernel/debug/tracing/events/sched/sched_process_fork/trigger 942ea272257SMauro Carvalho Chehab 943ea272257SMauro Carvalho Chehab # cat /sys/kernel/debug/tracing/events/sched/sched_process_fork/hist 944ea272257SMauro Carvalho Chehab # trigger info: hist:keys=child_comm:vals=hitcount:sort=hitcount:size=256 [paused] 945ea272257SMauro Carvalho Chehab 946ea272257SMauro Carvalho Chehab { child_comm: dconf worker } hitcount: 1 947ea272257SMauro Carvalho Chehab { child_comm: kthreadd } hitcount: 1 948ea272257SMauro Carvalho Chehab { child_comm: dconf worker } hitcount: 1 949ea272257SMauro Carvalho Chehab { child_comm: gdbus } hitcount: 1 950ea272257SMauro Carvalho Chehab { child_comm: ibus-daemon } hitcount: 1 951ea272257SMauro Carvalho Chehab { child_comm: Socket Thread } hitcount: 2 952ea272257SMauro Carvalho Chehab { child_comm: evolution-alarm } hitcount: 2 953ea272257SMauro Carvalho Chehab { child_comm: smbd } hitcount: 2 954ea272257SMauro Carvalho Chehab { child_comm: bash } hitcount: 3 955ea272257SMauro Carvalho Chehab { child_comm: whoopsie } hitcount: 3 956ea272257SMauro Carvalho Chehab { child_comm: compiz } hitcount: 3 957ea272257SMauro Carvalho Chehab { child_comm: evolution-sourc } hitcount: 4 958ea272257SMauro Carvalho Chehab { child_comm: pool } hitcount: 5 959ea272257SMauro Carvalho Chehab { child_comm: postgres } hitcount: 6 960ea272257SMauro Carvalho Chehab { child_comm: firefox } hitcount: 8 961ea272257SMauro Carvalho Chehab { child_comm: dhclient } hitcount: 10 962ea272257SMauro Carvalho Chehab { child_comm: emacs } hitcount: 12 963ea272257SMauro Carvalho Chehab { child_comm: dbus-daemon } hitcount: 20 964ea272257SMauro Carvalho Chehab { child_comm: nm-dispatcher.a } hitcount: 20 965ea272257SMauro Carvalho Chehab { child_comm: evolution } hitcount: 35 966ea272257SMauro Carvalho Chehab { child_comm: glib-pacrunner } hitcount: 59 967ea272257SMauro Carvalho Chehab 968ea272257SMauro Carvalho Chehab Totals: 969ea272257SMauro Carvalho Chehab Hits: 199 970ea272257SMauro Carvalho Chehab Entries: 21 971ea272257SMauro Carvalho Chehab Dropped: 0 972ea272257SMauro Carvalho Chehab 973ea272257SMauro Carvalho Chehab To manually continue having the trigger aggregate events, append 974ea272257SMauro Carvalho Chehab :cont instead. Notice that the trigger info displays as [active] 975ea272257SMauro Carvalho Chehab again, and the data has changed:: 976ea272257SMauro Carvalho Chehab 977ea272257SMauro Carvalho Chehab # echo 'hist:key=child_comm:val=hitcount:size=256:cont' >> \ 978ea272257SMauro Carvalho Chehab /sys/kernel/debug/tracing/events/sched/sched_process_fork/trigger 979ea272257SMauro Carvalho Chehab 980ea272257SMauro Carvalho Chehab # cat /sys/kernel/debug/tracing/events/sched/sched_process_fork/hist 981ea272257SMauro Carvalho Chehab # trigger info: hist:keys=child_comm:vals=hitcount:sort=hitcount:size=256 [active] 982ea272257SMauro Carvalho Chehab 983ea272257SMauro Carvalho Chehab { child_comm: dconf worker } hitcount: 1 984ea272257SMauro Carvalho Chehab { child_comm: dconf worker } hitcount: 1 985ea272257SMauro Carvalho Chehab { child_comm: kthreadd } hitcount: 1 986ea272257SMauro Carvalho Chehab { child_comm: gdbus } hitcount: 1 987ea272257SMauro Carvalho Chehab { child_comm: ibus-daemon } hitcount: 1 988ea272257SMauro Carvalho Chehab { child_comm: Socket Thread } hitcount: 2 989ea272257SMauro Carvalho Chehab { child_comm: evolution-alarm } hitcount: 2 990ea272257SMauro Carvalho Chehab { child_comm: smbd } hitcount: 2 991ea272257SMauro Carvalho Chehab { child_comm: whoopsie } hitcount: 3 992ea272257SMauro Carvalho Chehab { child_comm: compiz } hitcount: 3 993ea272257SMauro Carvalho Chehab { child_comm: evolution-sourc } hitcount: 4 994ea272257SMauro Carvalho Chehab { child_comm: bash } hitcount: 5 995ea272257SMauro Carvalho Chehab { child_comm: pool } hitcount: 5 996ea272257SMauro Carvalho Chehab { child_comm: postgres } hitcount: 6 997ea272257SMauro Carvalho Chehab { child_comm: firefox } hitcount: 8 998ea272257SMauro Carvalho Chehab { child_comm: dhclient } hitcount: 11 999ea272257SMauro Carvalho Chehab { child_comm: emacs } hitcount: 12 1000ea272257SMauro Carvalho Chehab { child_comm: dbus-daemon } hitcount: 22 1001ea272257SMauro Carvalho Chehab { child_comm: nm-dispatcher.a } hitcount: 22 1002ea272257SMauro Carvalho Chehab { child_comm: evolution } hitcount: 35 1003ea272257SMauro Carvalho Chehab { child_comm: glib-pacrunner } hitcount: 59 1004ea272257SMauro Carvalho Chehab 1005ea272257SMauro Carvalho Chehab Totals: 1006ea272257SMauro Carvalho Chehab Hits: 206 1007ea272257SMauro Carvalho Chehab Entries: 21 1008ea272257SMauro Carvalho Chehab Dropped: 0 1009ea272257SMauro Carvalho Chehab 1010ea272257SMauro Carvalho Chehab The previous example showed how to start and stop a hist trigger by 1011ea272257SMauro Carvalho Chehab appending 'pause' and 'continue' to the hist trigger command. A 1012ea272257SMauro Carvalho Chehab hist trigger can also be started in a paused state by initially 1013ea272257SMauro Carvalho Chehab starting the trigger with ':pause' appended. This allows you to 1014ea272257SMauro Carvalho Chehab start the trigger only when you're ready to start collecting data 1015ea272257SMauro Carvalho Chehab and not before. For example, you could start the trigger in a 1016ea272257SMauro Carvalho Chehab paused state, then unpause it and do something you want to measure, 1017ea272257SMauro Carvalho Chehab then pause the trigger again when done. 1018ea272257SMauro Carvalho Chehab 1019ea272257SMauro Carvalho Chehab Of course, doing this manually can be difficult and error-prone, but 1020ea272257SMauro Carvalho Chehab it is possible to automatically start and stop a hist trigger based 1021ea272257SMauro Carvalho Chehab on some condition, via the enable_hist and disable_hist triggers. 1022ea272257SMauro Carvalho Chehab 1023ea272257SMauro Carvalho Chehab For example, suppose we wanted to take a look at the relative 1024ea272257SMauro Carvalho Chehab weights in terms of skb length for each callpath that leads to a 1025ea272257SMauro Carvalho Chehab netif_receieve_skb event when downloading a decent-sized file using 1026ea272257SMauro Carvalho Chehab wget. 1027ea272257SMauro Carvalho Chehab 1028ea272257SMauro Carvalho Chehab First we set up an initially paused stacktrace trigger on the 1029ea272257SMauro Carvalho Chehab netif_receive_skb event:: 1030ea272257SMauro Carvalho Chehab 1031ea272257SMauro Carvalho Chehab # echo 'hist:key=stacktrace:vals=len:pause' > \ 1032ea272257SMauro Carvalho Chehab /sys/kernel/debug/tracing/events/net/netif_receive_skb/trigger 1033ea272257SMauro Carvalho Chehab 1034ea272257SMauro Carvalho Chehab Next, we set up an 'enable_hist' trigger on the sched_process_exec 1035ea272257SMauro Carvalho Chehab event, with an 'if filename==/usr/bin/wget' filter. The effect of 1036ea272257SMauro Carvalho Chehab this new trigger is that it will 'unpause' the hist trigger we just 1037ea272257SMauro Carvalho Chehab set up on netif_receive_skb if and only if it sees a 1038ea272257SMauro Carvalho Chehab sched_process_exec event with a filename of '/usr/bin/wget'. When 1039ea272257SMauro Carvalho Chehab that happens, all netif_receive_skb events are aggregated into a 1040ea272257SMauro Carvalho Chehab hash table keyed on stacktrace:: 1041ea272257SMauro Carvalho Chehab 1042ea272257SMauro Carvalho Chehab # echo 'enable_hist:net:netif_receive_skb if filename==/usr/bin/wget' > \ 1043ea272257SMauro Carvalho Chehab /sys/kernel/debug/tracing/events/sched/sched_process_exec/trigger 1044ea272257SMauro Carvalho Chehab 1045ea272257SMauro Carvalho Chehab The aggregation continues until the netif_receive_skb is paused 1046ea272257SMauro Carvalho Chehab again, which is what the following disable_hist event does by 1047ea272257SMauro Carvalho Chehab creating a similar setup on the sched_process_exit event, using the 1048ea272257SMauro Carvalho Chehab filter 'comm==wget':: 1049ea272257SMauro Carvalho Chehab 1050ea272257SMauro Carvalho Chehab # echo 'disable_hist:net:netif_receive_skb if comm==wget' > \ 1051ea272257SMauro Carvalho Chehab /sys/kernel/debug/tracing/events/sched/sched_process_exit/trigger 1052ea272257SMauro Carvalho Chehab 1053ea272257SMauro Carvalho Chehab Whenever a process exits and the comm field of the disable_hist 1054ea272257SMauro Carvalho Chehab trigger filter matches 'comm==wget', the netif_receive_skb hist 1055ea272257SMauro Carvalho Chehab trigger is disabled. 1056ea272257SMauro Carvalho Chehab 1057ea272257SMauro Carvalho Chehab The overall effect is that netif_receive_skb events are aggregated 1058ea272257SMauro Carvalho Chehab into the hash table for only the duration of the wget. Executing a 1059ea272257SMauro Carvalho Chehab wget command and then listing the 'hist' file will display the 1060ea272257SMauro Carvalho Chehab output generated by the wget command:: 1061ea272257SMauro Carvalho Chehab 1062ea272257SMauro Carvalho Chehab $ wget https://www.kernel.org/pub/linux/kernel/v3.x/patch-3.19.xz 1063ea272257SMauro Carvalho Chehab 1064ea272257SMauro Carvalho Chehab # cat /sys/kernel/debug/tracing/events/net/netif_receive_skb/hist 1065ea272257SMauro Carvalho Chehab # trigger info: hist:keys=stacktrace:vals=len:sort=hitcount:size=2048 [paused] 1066ea272257SMauro Carvalho Chehab 1067ea272257SMauro Carvalho Chehab { stacktrace: 1068ea272257SMauro Carvalho Chehab __netif_receive_skb_core+0x46d/0x990 1069ea272257SMauro Carvalho Chehab __netif_receive_skb+0x18/0x60 1070ea272257SMauro Carvalho Chehab netif_receive_skb_internal+0x23/0x90 1071ea272257SMauro Carvalho Chehab napi_gro_receive+0xc8/0x100 1072ea272257SMauro Carvalho Chehab ieee80211_deliver_skb+0xd6/0x270 [mac80211] 1073ea272257SMauro Carvalho Chehab ieee80211_rx_handlers+0xccf/0x22f0 [mac80211] 1074ea272257SMauro Carvalho Chehab ieee80211_prepare_and_rx_handle+0x4e7/0xc40 [mac80211] 1075ea272257SMauro Carvalho Chehab ieee80211_rx+0x31d/0x900 [mac80211] 1076ea272257SMauro Carvalho Chehab iwlagn_rx_reply_rx+0x3db/0x6f0 [iwldvm] 1077ea272257SMauro Carvalho Chehab iwl_rx_dispatch+0x8e/0xf0 [iwldvm] 1078ea272257SMauro Carvalho Chehab iwl_pcie_irq_handler+0xe3c/0x12f0 [iwlwifi] 1079ea272257SMauro Carvalho Chehab irq_thread_fn+0x20/0x50 1080ea272257SMauro Carvalho Chehab irq_thread+0x11f/0x150 1081ea272257SMauro Carvalho Chehab kthread+0xd2/0xf0 1082ea272257SMauro Carvalho Chehab ret_from_fork+0x42/0x70 1083ea272257SMauro Carvalho Chehab } hitcount: 85 len: 28884 1084ea272257SMauro Carvalho Chehab { stacktrace: 1085ea272257SMauro Carvalho Chehab __netif_receive_skb_core+0x46d/0x990 1086ea272257SMauro Carvalho Chehab __netif_receive_skb+0x18/0x60 1087ea272257SMauro Carvalho Chehab netif_receive_skb_internal+0x23/0x90 1088ea272257SMauro Carvalho Chehab napi_gro_complete+0xa4/0xe0 1089ea272257SMauro Carvalho Chehab dev_gro_receive+0x23a/0x360 1090ea272257SMauro Carvalho Chehab napi_gro_receive+0x30/0x100 1091ea272257SMauro Carvalho Chehab ieee80211_deliver_skb+0xd6/0x270 [mac80211] 1092ea272257SMauro Carvalho Chehab ieee80211_rx_handlers+0xccf/0x22f0 [mac80211] 1093ea272257SMauro Carvalho Chehab ieee80211_prepare_and_rx_handle+0x4e7/0xc40 [mac80211] 1094ea272257SMauro Carvalho Chehab ieee80211_rx+0x31d/0x900 [mac80211] 1095ea272257SMauro Carvalho Chehab iwlagn_rx_reply_rx+0x3db/0x6f0 [iwldvm] 1096ea272257SMauro Carvalho Chehab iwl_rx_dispatch+0x8e/0xf0 [iwldvm] 1097ea272257SMauro Carvalho Chehab iwl_pcie_irq_handler+0xe3c/0x12f0 [iwlwifi] 1098ea272257SMauro Carvalho Chehab irq_thread_fn+0x20/0x50 1099ea272257SMauro Carvalho Chehab irq_thread+0x11f/0x150 1100ea272257SMauro Carvalho Chehab kthread+0xd2/0xf0 1101ea272257SMauro Carvalho Chehab } hitcount: 98 len: 664329 1102ea272257SMauro Carvalho Chehab { stacktrace: 1103ea272257SMauro Carvalho Chehab __netif_receive_skb_core+0x46d/0x990 1104ea272257SMauro Carvalho Chehab __netif_receive_skb+0x18/0x60 1105ea272257SMauro Carvalho Chehab process_backlog+0xa8/0x150 1106ea272257SMauro Carvalho Chehab net_rx_action+0x15d/0x340 1107ea272257SMauro Carvalho Chehab __do_softirq+0x114/0x2c0 1108ea272257SMauro Carvalho Chehab do_softirq_own_stack+0x1c/0x30 1109ea272257SMauro Carvalho Chehab do_softirq+0x65/0x70 1110ea272257SMauro Carvalho Chehab __local_bh_enable_ip+0xb5/0xc0 1111ea272257SMauro Carvalho Chehab ip_finish_output+0x1f4/0x840 1112ea272257SMauro Carvalho Chehab ip_output+0x6b/0xc0 1113ea272257SMauro Carvalho Chehab ip_local_out_sk+0x31/0x40 1114ea272257SMauro Carvalho Chehab ip_send_skb+0x1a/0x50 1115ea272257SMauro Carvalho Chehab udp_send_skb+0x173/0x2a0 1116ea272257SMauro Carvalho Chehab udp_sendmsg+0x2bf/0x9f0 1117ea272257SMauro Carvalho Chehab inet_sendmsg+0x64/0xa0 1118ea272257SMauro Carvalho Chehab sock_sendmsg+0x3d/0x50 1119ea272257SMauro Carvalho Chehab } hitcount: 115 len: 13030 1120ea272257SMauro Carvalho Chehab { stacktrace: 1121ea272257SMauro Carvalho Chehab __netif_receive_skb_core+0x46d/0x990 1122ea272257SMauro Carvalho Chehab __netif_receive_skb+0x18/0x60 1123ea272257SMauro Carvalho Chehab netif_receive_skb_internal+0x23/0x90 1124ea272257SMauro Carvalho Chehab napi_gro_complete+0xa4/0xe0 1125ea272257SMauro Carvalho Chehab napi_gro_flush+0x6d/0x90 1126ea272257SMauro Carvalho Chehab iwl_pcie_irq_handler+0x92a/0x12f0 [iwlwifi] 1127ea272257SMauro Carvalho Chehab irq_thread_fn+0x20/0x50 1128ea272257SMauro Carvalho Chehab irq_thread+0x11f/0x150 1129ea272257SMauro Carvalho Chehab kthread+0xd2/0xf0 1130ea272257SMauro Carvalho Chehab ret_from_fork+0x42/0x70 1131ea272257SMauro Carvalho Chehab } hitcount: 934 len: 5512212 1132ea272257SMauro Carvalho Chehab 1133ea272257SMauro Carvalho Chehab Totals: 1134ea272257SMauro Carvalho Chehab Hits: 1232 1135ea272257SMauro Carvalho Chehab Entries: 4 1136ea272257SMauro Carvalho Chehab Dropped: 0 1137ea272257SMauro Carvalho Chehab 1138ea272257SMauro Carvalho Chehab The above shows all the netif_receive_skb callpaths and their total 1139ea272257SMauro Carvalho Chehab lengths for the duration of the wget command. 1140ea272257SMauro Carvalho Chehab 1141ea272257SMauro Carvalho Chehab The 'clear' hist trigger param can be used to clear the hash table. 1142ea272257SMauro Carvalho Chehab Suppose we wanted to try another run of the previous example but 1143ea272257SMauro Carvalho Chehab this time also wanted to see the complete list of events that went 1144ea272257SMauro Carvalho Chehab into the histogram. In order to avoid having to set everything up 1145ea272257SMauro Carvalho Chehab again, we can just clear the histogram first:: 1146ea272257SMauro Carvalho Chehab 1147ea272257SMauro Carvalho Chehab # echo 'hist:key=stacktrace:vals=len:clear' >> \ 1148ea272257SMauro Carvalho Chehab /sys/kernel/debug/tracing/events/net/netif_receive_skb/trigger 1149ea272257SMauro Carvalho Chehab 1150ea272257SMauro Carvalho Chehab Just to verify that it is in fact cleared, here's what we now see in 1151ea272257SMauro Carvalho Chehab the hist file:: 1152ea272257SMauro Carvalho Chehab 1153ea272257SMauro Carvalho Chehab # cat /sys/kernel/debug/tracing/events/net/netif_receive_skb/hist 1154ea272257SMauro Carvalho Chehab # trigger info: hist:keys=stacktrace:vals=len:sort=hitcount:size=2048 [paused] 1155ea272257SMauro Carvalho Chehab 1156ea272257SMauro Carvalho Chehab Totals: 1157ea272257SMauro Carvalho Chehab Hits: 0 1158ea272257SMauro Carvalho Chehab Entries: 0 1159ea272257SMauro Carvalho Chehab Dropped: 0 1160ea272257SMauro Carvalho Chehab 1161ea272257SMauro Carvalho Chehab Since we want to see the detailed list of every netif_receive_skb 1162ea272257SMauro Carvalho Chehab event occurring during the new run, which are in fact the same 1163ea272257SMauro Carvalho Chehab events being aggregated into the hash table, we add some additional 1164ea272257SMauro Carvalho Chehab 'enable_event' events to the triggering sched_process_exec and 1165ea272257SMauro Carvalho Chehab sched_process_exit events as such:: 1166ea272257SMauro Carvalho Chehab 1167ea272257SMauro Carvalho Chehab # echo 'enable_event:net:netif_receive_skb if filename==/usr/bin/wget' > \ 1168ea272257SMauro Carvalho Chehab /sys/kernel/debug/tracing/events/sched/sched_process_exec/trigger 1169ea272257SMauro Carvalho Chehab 1170ea272257SMauro Carvalho Chehab # echo 'disable_event:net:netif_receive_skb if comm==wget' > \ 1171ea272257SMauro Carvalho Chehab /sys/kernel/debug/tracing/events/sched/sched_process_exit/trigger 1172ea272257SMauro Carvalho Chehab 1173ea272257SMauro Carvalho Chehab If you read the trigger files for the sched_process_exec and 1174ea272257SMauro Carvalho Chehab sched_process_exit triggers, you should see two triggers for each: 1175ea272257SMauro Carvalho Chehab one enabling/disabling the hist aggregation and the other 1176ea272257SMauro Carvalho Chehab enabling/disabling the logging of events:: 1177ea272257SMauro Carvalho Chehab 1178ea272257SMauro Carvalho Chehab # cat /sys/kernel/debug/tracing/events/sched/sched_process_exec/trigger 1179ea272257SMauro Carvalho Chehab enable_event:net:netif_receive_skb:unlimited if filename==/usr/bin/wget 1180ea272257SMauro Carvalho Chehab enable_hist:net:netif_receive_skb:unlimited if filename==/usr/bin/wget 1181ea272257SMauro Carvalho Chehab 1182ea272257SMauro Carvalho Chehab # cat /sys/kernel/debug/tracing/events/sched/sched_process_exit/trigger 1183ea272257SMauro Carvalho Chehab enable_event:net:netif_receive_skb:unlimited if comm==wget 1184ea272257SMauro Carvalho Chehab disable_hist:net:netif_receive_skb:unlimited if comm==wget 1185ea272257SMauro Carvalho Chehab 1186ea272257SMauro Carvalho Chehab In other words, whenever either of the sched_process_exec or 1187ea272257SMauro Carvalho Chehab sched_process_exit events is hit and matches 'wget', it enables or 1188ea272257SMauro Carvalho Chehab disables both the histogram and the event log, and what you end up 1189ea272257SMauro Carvalho Chehab with is a hash table and set of events just covering the specified 1190ea272257SMauro Carvalho Chehab duration. Run the wget command again:: 1191ea272257SMauro Carvalho Chehab 1192ea272257SMauro Carvalho Chehab $ wget https://www.kernel.org/pub/linux/kernel/v3.x/patch-3.19.xz 1193ea272257SMauro Carvalho Chehab 1194ea272257SMauro Carvalho Chehab Displaying the 'hist' file should show something similar to what you 1195ea272257SMauro Carvalho Chehab saw in the last run, but this time you should also see the 1196ea272257SMauro Carvalho Chehab individual events in the trace file:: 1197ea272257SMauro Carvalho Chehab 1198ea272257SMauro Carvalho Chehab # cat /sys/kernel/debug/tracing/trace 1199ea272257SMauro Carvalho Chehab 1200ea272257SMauro Carvalho Chehab # tracer: nop 1201ea272257SMauro Carvalho Chehab # 1202ea272257SMauro Carvalho Chehab # entries-in-buffer/entries-written: 183/1426 #P:4 1203ea272257SMauro Carvalho Chehab # 1204ea272257SMauro Carvalho Chehab # _-----=> irqs-off 1205ea272257SMauro Carvalho Chehab # / _----=> need-resched 1206ea272257SMauro Carvalho Chehab # | / _---=> hardirq/softirq 1207ea272257SMauro Carvalho Chehab # || / _--=> preempt-depth 1208ea272257SMauro Carvalho Chehab # ||| / delay 1209ea272257SMauro Carvalho Chehab # TASK-PID CPU# |||| TIMESTAMP FUNCTION 1210ea272257SMauro Carvalho Chehab # | | | |||| | | 1211ea272257SMauro Carvalho Chehab wget-15108 [000] ..s1 31769.606929: netif_receive_skb: dev=lo skbaddr=ffff88009c353100 len=60 1212ea272257SMauro Carvalho Chehab wget-15108 [000] ..s1 31769.606999: netif_receive_skb: dev=lo skbaddr=ffff88009c353200 len=60 1213ea272257SMauro Carvalho Chehab dnsmasq-1382 [000] ..s1 31769.677652: netif_receive_skb: dev=lo skbaddr=ffff88009c352b00 len=130 1214ea272257SMauro Carvalho Chehab dnsmasq-1382 [000] ..s1 31769.685917: netif_receive_skb: dev=lo skbaddr=ffff88009c352200 len=138 1215ea272257SMauro Carvalho Chehab ##### CPU 2 buffer started #### 1216ea272257SMauro Carvalho Chehab irq/29-iwlwifi-559 [002] ..s. 31772.031529: netif_receive_skb: dev=wlan0 skbaddr=ffff88009d433d00 len=2948 1217ea272257SMauro Carvalho Chehab irq/29-iwlwifi-559 [002] ..s. 31772.031572: netif_receive_skb: dev=wlan0 skbaddr=ffff88009d432200 len=1500 1218ea272257SMauro Carvalho Chehab irq/29-iwlwifi-559 [002] ..s. 31772.032196: netif_receive_skb: dev=wlan0 skbaddr=ffff88009d433100 len=2948 1219ea272257SMauro Carvalho Chehab irq/29-iwlwifi-559 [002] ..s. 31772.032761: netif_receive_skb: dev=wlan0 skbaddr=ffff88009d433000 len=2948 1220ea272257SMauro Carvalho Chehab irq/29-iwlwifi-559 [002] ..s. 31772.033220: netif_receive_skb: dev=wlan0 skbaddr=ffff88009d432e00 len=1500 1221ea272257SMauro Carvalho Chehab . 1222ea272257SMauro Carvalho Chehab . 1223ea272257SMauro Carvalho Chehab . 1224ea272257SMauro Carvalho Chehab 1225ea272257SMauro Carvalho Chehab The following example demonstrates how multiple hist triggers can be 1226ea272257SMauro Carvalho Chehab attached to a given event. This capability can be useful for 1227ea272257SMauro Carvalho Chehab creating a set of different summaries derived from the same set of 1228ea272257SMauro Carvalho Chehab events, or for comparing the effects of different filters, among 1229ea272257SMauro Carvalho Chehab other things:: 1230ea272257SMauro Carvalho Chehab 1231ea272257SMauro Carvalho Chehab # echo 'hist:keys=skbaddr.hex:vals=len if len < 0' >> \ 1232ea272257SMauro Carvalho Chehab /sys/kernel/debug/tracing/events/net/netif_receive_skb/trigger 1233ea272257SMauro Carvalho Chehab # echo 'hist:keys=skbaddr.hex:vals=len if len > 4096' >> \ 1234ea272257SMauro Carvalho Chehab /sys/kernel/debug/tracing/events/net/netif_receive_skb/trigger 1235ea272257SMauro Carvalho Chehab # echo 'hist:keys=skbaddr.hex:vals=len if len == 256' >> \ 1236ea272257SMauro Carvalho Chehab /sys/kernel/debug/tracing/events/net/netif_receive_skb/trigger 1237ea272257SMauro Carvalho Chehab # echo 'hist:keys=skbaddr.hex:vals=len' >> \ 1238ea272257SMauro Carvalho Chehab /sys/kernel/debug/tracing/events/net/netif_receive_skb/trigger 1239ea272257SMauro Carvalho Chehab # echo 'hist:keys=len:vals=common_preempt_count' >> \ 1240ea272257SMauro Carvalho Chehab /sys/kernel/debug/tracing/events/net/netif_receive_skb/trigger 1241ea272257SMauro Carvalho Chehab 1242ea272257SMauro Carvalho Chehab The above set of commands create four triggers differing only in 1243ea272257SMauro Carvalho Chehab their filters, along with a completely different though fairly 1244ea272257SMauro Carvalho Chehab nonsensical trigger. Note that in order to append multiple hist 1245ea272257SMauro Carvalho Chehab triggers to the same file, you should use the '>>' operator to 1246ea272257SMauro Carvalho Chehab append them ('>' will also add the new hist trigger, but will remove 1247ea272257SMauro Carvalho Chehab any existing hist triggers beforehand). 1248ea272257SMauro Carvalho Chehab 1249ea272257SMauro Carvalho Chehab Displaying the contents of the 'hist' file for the event shows the 1250ea272257SMauro Carvalho Chehab contents of all five histograms:: 1251ea272257SMauro Carvalho Chehab 1252ea272257SMauro Carvalho Chehab # cat /sys/kernel/debug/tracing/events/net/netif_receive_skb/hist 1253ea272257SMauro Carvalho Chehab 1254ea272257SMauro Carvalho Chehab # event histogram 1255ea272257SMauro Carvalho Chehab # 1256ea272257SMauro Carvalho Chehab # trigger info: hist:keys=len:vals=hitcount,common_preempt_count:sort=hitcount:size=2048 [active] 1257ea272257SMauro Carvalho Chehab # 1258ea272257SMauro Carvalho Chehab 1259ea272257SMauro Carvalho Chehab { len: 176 } hitcount: 1 common_preempt_count: 0 1260ea272257SMauro Carvalho Chehab { len: 223 } hitcount: 1 common_preempt_count: 0 1261ea272257SMauro Carvalho Chehab { len: 4854 } hitcount: 1 common_preempt_count: 0 1262ea272257SMauro Carvalho Chehab { len: 395 } hitcount: 1 common_preempt_count: 0 1263ea272257SMauro Carvalho Chehab { len: 177 } hitcount: 1 common_preempt_count: 0 1264ea272257SMauro Carvalho Chehab { len: 446 } hitcount: 1 common_preempt_count: 0 1265ea272257SMauro Carvalho Chehab { len: 1601 } hitcount: 1 common_preempt_count: 0 1266ea272257SMauro Carvalho Chehab . 1267ea272257SMauro Carvalho Chehab . 1268ea272257SMauro Carvalho Chehab . 1269ea272257SMauro Carvalho Chehab { len: 1280 } hitcount: 66 common_preempt_count: 0 1270ea272257SMauro Carvalho Chehab { len: 116 } hitcount: 81 common_preempt_count: 40 1271ea272257SMauro Carvalho Chehab { len: 708 } hitcount: 112 common_preempt_count: 0 1272ea272257SMauro Carvalho Chehab { len: 46 } hitcount: 221 common_preempt_count: 0 1273ea272257SMauro Carvalho Chehab { len: 1264 } hitcount: 458 common_preempt_count: 0 1274ea272257SMauro Carvalho Chehab 1275ea272257SMauro Carvalho Chehab Totals: 1276ea272257SMauro Carvalho Chehab Hits: 1428 1277ea272257SMauro Carvalho Chehab Entries: 147 1278ea272257SMauro Carvalho Chehab Dropped: 0 1279ea272257SMauro Carvalho Chehab 1280ea272257SMauro Carvalho Chehab 1281ea272257SMauro Carvalho Chehab # event histogram 1282ea272257SMauro Carvalho Chehab # 1283ea272257SMauro Carvalho Chehab # trigger info: hist:keys=skbaddr.hex:vals=hitcount,len:sort=hitcount:size=2048 [active] 1284ea272257SMauro Carvalho Chehab # 1285ea272257SMauro Carvalho Chehab 1286ea272257SMauro Carvalho Chehab { skbaddr: ffff8800baee5e00 } hitcount: 1 len: 130 1287ea272257SMauro Carvalho Chehab { skbaddr: ffff88005f3d5600 } hitcount: 1 len: 1280 1288ea272257SMauro Carvalho Chehab { skbaddr: ffff88005f3d4900 } hitcount: 1 len: 1280 1289ea272257SMauro Carvalho Chehab { skbaddr: ffff88009fed6300 } hitcount: 1 len: 115 1290ea272257SMauro Carvalho Chehab { skbaddr: ffff88009fe0ad00 } hitcount: 1 len: 115 1291ea272257SMauro Carvalho Chehab { skbaddr: ffff88008cdb1900 } hitcount: 1 len: 46 1292ea272257SMauro Carvalho Chehab { skbaddr: ffff880064b5ef00 } hitcount: 1 len: 118 1293ea272257SMauro Carvalho Chehab { skbaddr: ffff880044e3c700 } hitcount: 1 len: 60 1294ea272257SMauro Carvalho Chehab { skbaddr: ffff880100065900 } hitcount: 1 len: 46 1295ea272257SMauro Carvalho Chehab { skbaddr: ffff8800d46bd500 } hitcount: 1 len: 116 1296ea272257SMauro Carvalho Chehab { skbaddr: ffff88005f3d5f00 } hitcount: 1 len: 1280 1297ea272257SMauro Carvalho Chehab { skbaddr: ffff880100064700 } hitcount: 1 len: 365 1298ea272257SMauro Carvalho Chehab { skbaddr: ffff8800badb6f00 } hitcount: 1 len: 60 1299ea272257SMauro Carvalho Chehab . 1300ea272257SMauro Carvalho Chehab . 1301ea272257SMauro Carvalho Chehab . 1302ea272257SMauro Carvalho Chehab { skbaddr: ffff88009fe0be00 } hitcount: 27 len: 24677 1303ea272257SMauro Carvalho Chehab { skbaddr: ffff88009fe0a400 } hitcount: 27 len: 23052 1304ea272257SMauro Carvalho Chehab { skbaddr: ffff88009fe0b700 } hitcount: 31 len: 25589 1305ea272257SMauro Carvalho Chehab { skbaddr: ffff88009fe0b600 } hitcount: 32 len: 27326 1306ea272257SMauro Carvalho Chehab { skbaddr: ffff88006a462800 } hitcount: 68 len: 71678 1307ea272257SMauro Carvalho Chehab { skbaddr: ffff88006a463700 } hitcount: 70 len: 72678 1308ea272257SMauro Carvalho Chehab { skbaddr: ffff88006a462b00 } hitcount: 71 len: 77589 1309ea272257SMauro Carvalho Chehab { skbaddr: ffff88006a463600 } hitcount: 73 len: 71307 1310ea272257SMauro Carvalho Chehab { skbaddr: ffff88006a462200 } hitcount: 81 len: 81032 1311ea272257SMauro Carvalho Chehab 1312ea272257SMauro Carvalho Chehab Totals: 1313ea272257SMauro Carvalho Chehab Hits: 1451 1314ea272257SMauro Carvalho Chehab Entries: 318 1315ea272257SMauro Carvalho Chehab Dropped: 0 1316ea272257SMauro Carvalho Chehab 1317ea272257SMauro Carvalho Chehab 1318ea272257SMauro Carvalho Chehab # event histogram 1319ea272257SMauro Carvalho Chehab # 1320ea272257SMauro Carvalho Chehab # trigger info: hist:keys=skbaddr.hex:vals=hitcount,len:sort=hitcount:size=2048 if len == 256 [active] 1321ea272257SMauro Carvalho Chehab # 1322ea272257SMauro Carvalho Chehab 1323ea272257SMauro Carvalho Chehab 1324ea272257SMauro Carvalho Chehab Totals: 1325ea272257SMauro Carvalho Chehab Hits: 0 1326ea272257SMauro Carvalho Chehab Entries: 0 1327ea272257SMauro Carvalho Chehab Dropped: 0 1328ea272257SMauro Carvalho Chehab 1329ea272257SMauro Carvalho Chehab 1330ea272257SMauro Carvalho Chehab # event histogram 1331ea272257SMauro Carvalho Chehab # 1332ea272257SMauro Carvalho Chehab # trigger info: hist:keys=skbaddr.hex:vals=hitcount,len:sort=hitcount:size=2048 if len > 4096 [active] 1333ea272257SMauro Carvalho Chehab # 1334ea272257SMauro Carvalho Chehab 1335ea272257SMauro Carvalho Chehab { skbaddr: ffff88009fd2c300 } hitcount: 1 len: 7212 1336ea272257SMauro Carvalho Chehab { skbaddr: ffff8800d2bcce00 } hitcount: 1 len: 7212 1337ea272257SMauro Carvalho Chehab { skbaddr: ffff8800d2bcd700 } hitcount: 1 len: 7212 1338ea272257SMauro Carvalho Chehab { skbaddr: ffff8800d2bcda00 } hitcount: 1 len: 21492 1339ea272257SMauro Carvalho Chehab { skbaddr: ffff8800ae2e2d00 } hitcount: 1 len: 7212 1340ea272257SMauro Carvalho Chehab { skbaddr: ffff8800d2bcdb00 } hitcount: 1 len: 7212 1341ea272257SMauro Carvalho Chehab { skbaddr: ffff88006a4df500 } hitcount: 1 len: 4854 1342ea272257SMauro Carvalho Chehab { skbaddr: ffff88008ce47b00 } hitcount: 1 len: 18636 1343ea272257SMauro Carvalho Chehab { skbaddr: ffff8800ae2e2200 } hitcount: 1 len: 12924 1344ea272257SMauro Carvalho Chehab { skbaddr: ffff88005f3e1000 } hitcount: 1 len: 4356 1345ea272257SMauro Carvalho Chehab { skbaddr: ffff8800d2bcdc00 } hitcount: 2 len: 24420 1346ea272257SMauro Carvalho Chehab { skbaddr: ffff8800d2bcc200 } hitcount: 2 len: 12996 1347ea272257SMauro Carvalho Chehab 1348ea272257SMauro Carvalho Chehab Totals: 1349ea272257SMauro Carvalho Chehab Hits: 14 1350ea272257SMauro Carvalho Chehab Entries: 12 1351ea272257SMauro Carvalho Chehab Dropped: 0 1352ea272257SMauro Carvalho Chehab 1353ea272257SMauro Carvalho Chehab 1354ea272257SMauro Carvalho Chehab # event histogram 1355ea272257SMauro Carvalho Chehab # 1356ea272257SMauro Carvalho Chehab # trigger info: hist:keys=skbaddr.hex:vals=hitcount,len:sort=hitcount:size=2048 if len < 0 [active] 1357ea272257SMauro Carvalho Chehab # 1358ea272257SMauro Carvalho Chehab 1359ea272257SMauro Carvalho Chehab 1360ea272257SMauro Carvalho Chehab Totals: 1361ea272257SMauro Carvalho Chehab Hits: 0 1362ea272257SMauro Carvalho Chehab Entries: 0 1363ea272257SMauro Carvalho Chehab Dropped: 0 1364ea272257SMauro Carvalho Chehab 1365ea272257SMauro Carvalho Chehab Named triggers can be used to have triggers share a common set of 1366ea272257SMauro Carvalho Chehab histogram data. This capability is mostly useful for combining the 1367ea272257SMauro Carvalho Chehab output of events generated by tracepoints contained inside inline 1368ea272257SMauro Carvalho Chehab functions, but names can be used in a hist trigger on any event. 1369ea272257SMauro Carvalho Chehab For example, these two triggers when hit will update the same 'len' 1370ea272257SMauro Carvalho Chehab field in the shared 'foo' histogram data:: 1371ea272257SMauro Carvalho Chehab 1372ea272257SMauro Carvalho Chehab # echo 'hist:name=foo:keys=skbaddr.hex:vals=len' > \ 1373ea272257SMauro Carvalho Chehab /sys/kernel/debug/tracing/events/net/netif_receive_skb/trigger 1374ea272257SMauro Carvalho Chehab # echo 'hist:name=foo:keys=skbaddr.hex:vals=len' > \ 1375ea272257SMauro Carvalho Chehab /sys/kernel/debug/tracing/events/net/netif_rx/trigger 1376ea272257SMauro Carvalho Chehab 1377ea272257SMauro Carvalho Chehab You can see that they're updating common histogram data by reading 1378ea272257SMauro Carvalho Chehab each event's hist files at the same time:: 1379ea272257SMauro Carvalho Chehab 1380ea272257SMauro Carvalho Chehab # cat /sys/kernel/debug/tracing/events/net/netif_receive_skb/hist; 1381ea272257SMauro Carvalho Chehab cat /sys/kernel/debug/tracing/events/net/netif_rx/hist 1382ea272257SMauro Carvalho Chehab 1383ea272257SMauro Carvalho Chehab # event histogram 1384ea272257SMauro Carvalho Chehab # 1385ea272257SMauro Carvalho Chehab # trigger info: hist:name=foo:keys=skbaddr.hex:vals=hitcount,len:sort=hitcount:size=2048 [active] 1386ea272257SMauro Carvalho Chehab # 1387ea272257SMauro Carvalho Chehab 1388ea272257SMauro Carvalho Chehab { skbaddr: ffff88000ad53500 } hitcount: 1 len: 46 1389ea272257SMauro Carvalho Chehab { skbaddr: ffff8800af5a1500 } hitcount: 1 len: 76 1390ea272257SMauro Carvalho Chehab { skbaddr: ffff8800d62a1900 } hitcount: 1 len: 46 1391ea272257SMauro Carvalho Chehab { skbaddr: ffff8800d2bccb00 } hitcount: 1 len: 468 1392ea272257SMauro Carvalho Chehab { skbaddr: ffff8800d3c69900 } hitcount: 1 len: 46 1393ea272257SMauro Carvalho Chehab { skbaddr: ffff88009ff09100 } hitcount: 1 len: 52 1394ea272257SMauro Carvalho Chehab { skbaddr: ffff88010f13ab00 } hitcount: 1 len: 168 1395ea272257SMauro Carvalho Chehab { skbaddr: ffff88006a54f400 } hitcount: 1 len: 46 1396ea272257SMauro Carvalho Chehab { skbaddr: ffff8800d2bcc500 } hitcount: 1 len: 260 1397ea272257SMauro Carvalho Chehab { skbaddr: ffff880064505000 } hitcount: 1 len: 46 1398ea272257SMauro Carvalho Chehab { skbaddr: ffff8800baf24e00 } hitcount: 1 len: 32 1399ea272257SMauro Carvalho Chehab { skbaddr: ffff88009fe0ad00 } hitcount: 1 len: 46 1400ea272257SMauro Carvalho Chehab { skbaddr: ffff8800d3edff00 } hitcount: 1 len: 44 1401ea272257SMauro Carvalho Chehab { skbaddr: ffff88009fe0b400 } hitcount: 1 len: 168 1402ea272257SMauro Carvalho Chehab { skbaddr: ffff8800a1c55a00 } hitcount: 1 len: 40 1403ea272257SMauro Carvalho Chehab { skbaddr: ffff8800d2bcd100 } hitcount: 1 len: 40 1404ea272257SMauro Carvalho Chehab { skbaddr: ffff880064505f00 } hitcount: 1 len: 174 1405ea272257SMauro Carvalho Chehab { skbaddr: ffff8800a8bff200 } hitcount: 1 len: 160 1406ea272257SMauro Carvalho Chehab { skbaddr: ffff880044e3cc00 } hitcount: 1 len: 76 1407ea272257SMauro Carvalho Chehab { skbaddr: ffff8800a8bfe700 } hitcount: 1 len: 46 1408ea272257SMauro Carvalho Chehab { skbaddr: ffff8800d2bcdc00 } hitcount: 1 len: 32 1409ea272257SMauro Carvalho Chehab { skbaddr: ffff8800a1f64800 } hitcount: 1 len: 46 1410ea272257SMauro Carvalho Chehab { skbaddr: ffff8800d2bcde00 } hitcount: 1 len: 988 1411ea272257SMauro Carvalho Chehab { skbaddr: ffff88006a5dea00 } hitcount: 1 len: 46 1412ea272257SMauro Carvalho Chehab { skbaddr: ffff88002e37a200 } hitcount: 1 len: 44 1413ea272257SMauro Carvalho Chehab { skbaddr: ffff8800a1f32c00 } hitcount: 2 len: 676 1414ea272257SMauro Carvalho Chehab { skbaddr: ffff88000ad52600 } hitcount: 2 len: 107 1415ea272257SMauro Carvalho Chehab { skbaddr: ffff8800a1f91e00 } hitcount: 2 len: 92 1416ea272257SMauro Carvalho Chehab { skbaddr: ffff8800af5a0200 } hitcount: 2 len: 142 1417ea272257SMauro Carvalho Chehab { skbaddr: ffff8800d2bcc600 } hitcount: 2 len: 220 1418ea272257SMauro Carvalho Chehab { skbaddr: ffff8800ba36f500 } hitcount: 2 len: 92 1419ea272257SMauro Carvalho Chehab { skbaddr: ffff8800d021f800 } hitcount: 2 len: 92 1420ea272257SMauro Carvalho Chehab { skbaddr: ffff8800a1f33600 } hitcount: 2 len: 675 1421ea272257SMauro Carvalho Chehab { skbaddr: ffff8800a8bfff00 } hitcount: 3 len: 138 1422ea272257SMauro Carvalho Chehab { skbaddr: ffff8800d62a1300 } hitcount: 3 len: 138 1423ea272257SMauro Carvalho Chehab { skbaddr: ffff88002e37a100 } hitcount: 4 len: 184 1424ea272257SMauro Carvalho Chehab { skbaddr: ffff880064504400 } hitcount: 4 len: 184 1425ea272257SMauro Carvalho Chehab { skbaddr: ffff8800a8bfec00 } hitcount: 4 len: 184 1426ea272257SMauro Carvalho Chehab { skbaddr: ffff88000ad53700 } hitcount: 5 len: 230 1427ea272257SMauro Carvalho Chehab { skbaddr: ffff8800d2bcdb00 } hitcount: 5 len: 196 1428ea272257SMauro Carvalho Chehab { skbaddr: ffff8800a1f90000 } hitcount: 6 len: 276 1429ea272257SMauro Carvalho Chehab { skbaddr: ffff88006a54f900 } hitcount: 6 len: 276 1430ea272257SMauro Carvalho Chehab 1431ea272257SMauro Carvalho Chehab Totals: 1432ea272257SMauro Carvalho Chehab Hits: 81 1433ea272257SMauro Carvalho Chehab Entries: 42 1434ea272257SMauro Carvalho Chehab Dropped: 0 1435ea272257SMauro Carvalho Chehab # event histogram 1436ea272257SMauro Carvalho Chehab # 1437ea272257SMauro Carvalho Chehab # trigger info: hist:name=foo:keys=skbaddr.hex:vals=hitcount,len:sort=hitcount:size=2048 [active] 1438ea272257SMauro Carvalho Chehab # 1439ea272257SMauro Carvalho Chehab 1440ea272257SMauro Carvalho Chehab { skbaddr: ffff88000ad53500 } hitcount: 1 len: 46 1441ea272257SMauro Carvalho Chehab { skbaddr: ffff8800af5a1500 } hitcount: 1 len: 76 1442ea272257SMauro Carvalho Chehab { skbaddr: ffff8800d62a1900 } hitcount: 1 len: 46 1443ea272257SMauro Carvalho Chehab { skbaddr: ffff8800d2bccb00 } hitcount: 1 len: 468 1444ea272257SMauro Carvalho Chehab { skbaddr: ffff8800d3c69900 } hitcount: 1 len: 46 1445ea272257SMauro Carvalho Chehab { skbaddr: ffff88009ff09100 } hitcount: 1 len: 52 1446ea272257SMauro Carvalho Chehab { skbaddr: ffff88010f13ab00 } hitcount: 1 len: 168 1447ea272257SMauro Carvalho Chehab { skbaddr: ffff88006a54f400 } hitcount: 1 len: 46 1448ea272257SMauro Carvalho Chehab { skbaddr: ffff8800d2bcc500 } hitcount: 1 len: 260 1449ea272257SMauro Carvalho Chehab { skbaddr: ffff880064505000 } hitcount: 1 len: 46 1450ea272257SMauro Carvalho Chehab { skbaddr: ffff8800baf24e00 } hitcount: 1 len: 32 1451ea272257SMauro Carvalho Chehab { skbaddr: ffff88009fe0ad00 } hitcount: 1 len: 46 1452ea272257SMauro Carvalho Chehab { skbaddr: ffff8800d3edff00 } hitcount: 1 len: 44 1453ea272257SMauro Carvalho Chehab { skbaddr: ffff88009fe0b400 } hitcount: 1 len: 168 1454ea272257SMauro Carvalho Chehab { skbaddr: ffff8800a1c55a00 } hitcount: 1 len: 40 1455ea272257SMauro Carvalho Chehab { skbaddr: ffff8800d2bcd100 } hitcount: 1 len: 40 1456ea272257SMauro Carvalho Chehab { skbaddr: ffff880064505f00 } hitcount: 1 len: 174 1457ea272257SMauro Carvalho Chehab { skbaddr: ffff8800a8bff200 } hitcount: 1 len: 160 1458ea272257SMauro Carvalho Chehab { skbaddr: ffff880044e3cc00 } hitcount: 1 len: 76 1459ea272257SMauro Carvalho Chehab { skbaddr: ffff8800a8bfe700 } hitcount: 1 len: 46 1460ea272257SMauro Carvalho Chehab { skbaddr: ffff8800d2bcdc00 } hitcount: 1 len: 32 1461ea272257SMauro Carvalho Chehab { skbaddr: ffff8800a1f64800 } hitcount: 1 len: 46 1462ea272257SMauro Carvalho Chehab { skbaddr: ffff8800d2bcde00 } hitcount: 1 len: 988 1463ea272257SMauro Carvalho Chehab { skbaddr: ffff88006a5dea00 } hitcount: 1 len: 46 1464ea272257SMauro Carvalho Chehab { skbaddr: ffff88002e37a200 } hitcount: 1 len: 44 1465ea272257SMauro Carvalho Chehab { skbaddr: ffff8800a1f32c00 } hitcount: 2 len: 676 1466ea272257SMauro Carvalho Chehab { skbaddr: ffff88000ad52600 } hitcount: 2 len: 107 1467ea272257SMauro Carvalho Chehab { skbaddr: ffff8800a1f91e00 } hitcount: 2 len: 92 1468ea272257SMauro Carvalho Chehab { skbaddr: ffff8800af5a0200 } hitcount: 2 len: 142 1469ea272257SMauro Carvalho Chehab { skbaddr: ffff8800d2bcc600 } hitcount: 2 len: 220 1470ea272257SMauro Carvalho Chehab { skbaddr: ffff8800ba36f500 } hitcount: 2 len: 92 1471ea272257SMauro Carvalho Chehab { skbaddr: ffff8800d021f800 } hitcount: 2 len: 92 1472ea272257SMauro Carvalho Chehab { skbaddr: ffff8800a1f33600 } hitcount: 2 len: 675 1473ea272257SMauro Carvalho Chehab { skbaddr: ffff8800a8bfff00 } hitcount: 3 len: 138 1474ea272257SMauro Carvalho Chehab { skbaddr: ffff8800d62a1300 } hitcount: 3 len: 138 1475ea272257SMauro Carvalho Chehab { skbaddr: ffff88002e37a100 } hitcount: 4 len: 184 1476ea272257SMauro Carvalho Chehab { skbaddr: ffff880064504400 } hitcount: 4 len: 184 1477ea272257SMauro Carvalho Chehab { skbaddr: ffff8800a8bfec00 } hitcount: 4 len: 184 1478ea272257SMauro Carvalho Chehab { skbaddr: ffff88000ad53700 } hitcount: 5 len: 230 1479ea272257SMauro Carvalho Chehab { skbaddr: ffff8800d2bcdb00 } hitcount: 5 len: 196 1480ea272257SMauro Carvalho Chehab { skbaddr: ffff8800a1f90000 } hitcount: 6 len: 276 1481ea272257SMauro Carvalho Chehab { skbaddr: ffff88006a54f900 } hitcount: 6 len: 276 1482ea272257SMauro Carvalho Chehab 1483ea272257SMauro Carvalho Chehab Totals: 1484ea272257SMauro Carvalho Chehab Hits: 81 1485ea272257SMauro Carvalho Chehab Entries: 42 1486ea272257SMauro Carvalho Chehab Dropped: 0 1487ea272257SMauro Carvalho Chehab 1488ea272257SMauro Carvalho Chehab And here's an example that shows how to combine histogram data from 1489ea272257SMauro Carvalho Chehab any two events even if they don't share any 'compatible' fields 1490ea272257SMauro Carvalho Chehab other than 'hitcount' and 'stacktrace'. These commands create a 1491ea272257SMauro Carvalho Chehab couple of triggers named 'bar' using those fields:: 1492ea272257SMauro Carvalho Chehab 1493ea272257SMauro Carvalho Chehab # echo 'hist:name=bar:key=stacktrace:val=hitcount' > \ 1494ea272257SMauro Carvalho Chehab /sys/kernel/debug/tracing/events/sched/sched_process_fork/trigger 1495ea272257SMauro Carvalho Chehab # echo 'hist:name=bar:key=stacktrace:val=hitcount' > \ 1496ea272257SMauro Carvalho Chehab /sys/kernel/debug/tracing/events/net/netif_rx/trigger 1497ea272257SMauro Carvalho Chehab 1498ea272257SMauro Carvalho Chehab And displaying the output of either shows some interesting if 1499ea272257SMauro Carvalho Chehab somewhat confusing output:: 1500ea272257SMauro Carvalho Chehab 1501ea272257SMauro Carvalho Chehab # cat /sys/kernel/debug/tracing/events/sched/sched_process_fork/hist 1502ea272257SMauro Carvalho Chehab # cat /sys/kernel/debug/tracing/events/net/netif_rx/hist 1503ea272257SMauro Carvalho Chehab 1504ea272257SMauro Carvalho Chehab # event histogram 1505ea272257SMauro Carvalho Chehab # 1506ea272257SMauro Carvalho Chehab # trigger info: hist:name=bar:keys=stacktrace:vals=hitcount:sort=hitcount:size=2048 [active] 1507ea272257SMauro Carvalho Chehab # 1508ea272257SMauro Carvalho Chehab 1509ea272257SMauro Carvalho Chehab { stacktrace: 1510ea272257SMauro Carvalho Chehab _do_fork+0x18e/0x330 1511ea272257SMauro Carvalho Chehab kernel_thread+0x29/0x30 1512ea272257SMauro Carvalho Chehab kthreadd+0x154/0x1b0 1513ea272257SMauro Carvalho Chehab ret_from_fork+0x3f/0x70 1514ea272257SMauro Carvalho Chehab } hitcount: 1 1515ea272257SMauro Carvalho Chehab { stacktrace: 1516ea272257SMauro Carvalho Chehab netif_rx_internal+0xb2/0xd0 1517ea272257SMauro Carvalho Chehab netif_rx_ni+0x20/0x70 1518ea272257SMauro Carvalho Chehab dev_loopback_xmit+0xaa/0xd0 1519ea272257SMauro Carvalho Chehab ip_mc_output+0x126/0x240 1520ea272257SMauro Carvalho Chehab ip_local_out_sk+0x31/0x40 1521ea272257SMauro Carvalho Chehab igmp_send_report+0x1e9/0x230 1522ea272257SMauro Carvalho Chehab igmp_timer_expire+0xe9/0x120 1523ea272257SMauro Carvalho Chehab call_timer_fn+0x39/0xf0 1524ea272257SMauro Carvalho Chehab run_timer_softirq+0x1e1/0x290 1525ea272257SMauro Carvalho Chehab __do_softirq+0xfd/0x290 1526ea272257SMauro Carvalho Chehab irq_exit+0x98/0xb0 1527ea272257SMauro Carvalho Chehab smp_apic_timer_interrupt+0x4a/0x60 1528ea272257SMauro Carvalho Chehab apic_timer_interrupt+0x6d/0x80 1529ea272257SMauro Carvalho Chehab cpuidle_enter+0x17/0x20 1530ea272257SMauro Carvalho Chehab call_cpuidle+0x3b/0x60 1531ea272257SMauro Carvalho Chehab cpu_startup_entry+0x22d/0x310 1532ea272257SMauro Carvalho Chehab } hitcount: 1 1533ea272257SMauro Carvalho Chehab { stacktrace: 1534ea272257SMauro Carvalho Chehab netif_rx_internal+0xb2/0xd0 1535ea272257SMauro Carvalho Chehab netif_rx_ni+0x20/0x70 1536ea272257SMauro Carvalho Chehab dev_loopback_xmit+0xaa/0xd0 1537ea272257SMauro Carvalho Chehab ip_mc_output+0x17f/0x240 1538ea272257SMauro Carvalho Chehab ip_local_out_sk+0x31/0x40 1539ea272257SMauro Carvalho Chehab ip_send_skb+0x1a/0x50 1540ea272257SMauro Carvalho Chehab udp_send_skb+0x13e/0x270 1541ea272257SMauro Carvalho Chehab udp_sendmsg+0x2bf/0x980 1542ea272257SMauro Carvalho Chehab inet_sendmsg+0x67/0xa0 1543ea272257SMauro Carvalho Chehab sock_sendmsg+0x38/0x50 1544ea272257SMauro Carvalho Chehab SYSC_sendto+0xef/0x170 1545ea272257SMauro Carvalho Chehab SyS_sendto+0xe/0x10 1546ea272257SMauro Carvalho Chehab entry_SYSCALL_64_fastpath+0x12/0x6a 1547ea272257SMauro Carvalho Chehab } hitcount: 2 1548ea272257SMauro Carvalho Chehab { stacktrace: 1549ea272257SMauro Carvalho Chehab netif_rx_internal+0xb2/0xd0 1550ea272257SMauro Carvalho Chehab netif_rx+0x1c/0x60 1551ea272257SMauro Carvalho Chehab loopback_xmit+0x6c/0xb0 1552ea272257SMauro Carvalho Chehab dev_hard_start_xmit+0x219/0x3a0 1553ea272257SMauro Carvalho Chehab __dev_queue_xmit+0x415/0x4f0 1554ea272257SMauro Carvalho Chehab dev_queue_xmit_sk+0x13/0x20 1555ea272257SMauro Carvalho Chehab ip_finish_output2+0x237/0x340 1556ea272257SMauro Carvalho Chehab ip_finish_output+0x113/0x1d0 1557ea272257SMauro Carvalho Chehab ip_output+0x66/0xc0 1558ea272257SMauro Carvalho Chehab ip_local_out_sk+0x31/0x40 1559ea272257SMauro Carvalho Chehab ip_send_skb+0x1a/0x50 1560ea272257SMauro Carvalho Chehab udp_send_skb+0x16d/0x270 1561ea272257SMauro Carvalho Chehab udp_sendmsg+0x2bf/0x980 1562ea272257SMauro Carvalho Chehab inet_sendmsg+0x67/0xa0 1563ea272257SMauro Carvalho Chehab sock_sendmsg+0x38/0x50 1564ea272257SMauro Carvalho Chehab ___sys_sendmsg+0x14e/0x270 1565ea272257SMauro Carvalho Chehab } hitcount: 76 1566ea272257SMauro Carvalho Chehab { stacktrace: 1567ea272257SMauro Carvalho Chehab netif_rx_internal+0xb2/0xd0 1568ea272257SMauro Carvalho Chehab netif_rx+0x1c/0x60 1569ea272257SMauro Carvalho Chehab loopback_xmit+0x6c/0xb0 1570ea272257SMauro Carvalho Chehab dev_hard_start_xmit+0x219/0x3a0 1571ea272257SMauro Carvalho Chehab __dev_queue_xmit+0x415/0x4f0 1572ea272257SMauro Carvalho Chehab dev_queue_xmit_sk+0x13/0x20 1573ea272257SMauro Carvalho Chehab ip_finish_output2+0x237/0x340 1574ea272257SMauro Carvalho Chehab ip_finish_output+0x113/0x1d0 1575ea272257SMauro Carvalho Chehab ip_output+0x66/0xc0 1576ea272257SMauro Carvalho Chehab ip_local_out_sk+0x31/0x40 1577ea272257SMauro Carvalho Chehab ip_send_skb+0x1a/0x50 1578ea272257SMauro Carvalho Chehab udp_send_skb+0x16d/0x270 1579ea272257SMauro Carvalho Chehab udp_sendmsg+0x2bf/0x980 1580ea272257SMauro Carvalho Chehab inet_sendmsg+0x67/0xa0 1581ea272257SMauro Carvalho Chehab sock_sendmsg+0x38/0x50 1582ea272257SMauro Carvalho Chehab ___sys_sendmsg+0x269/0x270 1583ea272257SMauro Carvalho Chehab } hitcount: 77 1584ea272257SMauro Carvalho Chehab { stacktrace: 1585ea272257SMauro Carvalho Chehab netif_rx_internal+0xb2/0xd0 1586ea272257SMauro Carvalho Chehab netif_rx+0x1c/0x60 1587ea272257SMauro Carvalho Chehab loopback_xmit+0x6c/0xb0 1588ea272257SMauro Carvalho Chehab dev_hard_start_xmit+0x219/0x3a0 1589ea272257SMauro Carvalho Chehab __dev_queue_xmit+0x415/0x4f0 1590ea272257SMauro Carvalho Chehab dev_queue_xmit_sk+0x13/0x20 1591ea272257SMauro Carvalho Chehab ip_finish_output2+0x237/0x340 1592ea272257SMauro Carvalho Chehab ip_finish_output+0x113/0x1d0 1593ea272257SMauro Carvalho Chehab ip_output+0x66/0xc0 1594ea272257SMauro Carvalho Chehab ip_local_out_sk+0x31/0x40 1595ea272257SMauro Carvalho Chehab ip_send_skb+0x1a/0x50 1596ea272257SMauro Carvalho Chehab udp_send_skb+0x16d/0x270 1597ea272257SMauro Carvalho Chehab udp_sendmsg+0x2bf/0x980 1598ea272257SMauro Carvalho Chehab inet_sendmsg+0x67/0xa0 1599ea272257SMauro Carvalho Chehab sock_sendmsg+0x38/0x50 1600ea272257SMauro Carvalho Chehab SYSC_sendto+0xef/0x170 1601ea272257SMauro Carvalho Chehab } hitcount: 88 1602ea272257SMauro Carvalho Chehab { stacktrace: 1603ea272257SMauro Carvalho Chehab _do_fork+0x18e/0x330 1604ea272257SMauro Carvalho Chehab SyS_clone+0x19/0x20 1605ea272257SMauro Carvalho Chehab entry_SYSCALL_64_fastpath+0x12/0x6a 1606ea272257SMauro Carvalho Chehab } hitcount: 244 1607ea272257SMauro Carvalho Chehab 1608ea272257SMauro Carvalho Chehab Totals: 1609ea272257SMauro Carvalho Chehab Hits: 489 1610ea272257SMauro Carvalho Chehab Entries: 7 1611ea272257SMauro Carvalho Chehab Dropped: 0 1612ea272257SMauro Carvalho Chehab 1613ea272257SMauro Carvalho Chehab2.2 Inter-event hist triggers 1614ea272257SMauro Carvalho Chehab----------------------------- 1615ea272257SMauro Carvalho Chehab 1616ea272257SMauro Carvalho ChehabInter-event hist triggers are hist triggers that combine values from 1617ea272257SMauro Carvalho Chehabone or more other events and create a histogram using that data. Data 1618ea272257SMauro Carvalho Chehabfrom an inter-event histogram can in turn become the source for 1619ea272257SMauro Carvalho Chehabfurther combined histograms, thus providing a chain of related 1620ea272257SMauro Carvalho Chehabhistograms, which is important for some applications. 1621ea272257SMauro Carvalho Chehab 1622ea272257SMauro Carvalho ChehabThe most important example of an inter-event quantity that can be used 1623ea272257SMauro Carvalho Chehabin this manner is latency, which is simply a difference in timestamps 1624ea272257SMauro Carvalho Chehabbetween two events. Although latency is the most important 1625ea272257SMauro Carvalho Chehabinter-event quantity, note that because the support is completely 1626ea272257SMauro Carvalho Chehabgeneral across the trace event subsystem, any event field can be used 1627ea272257SMauro Carvalho Chehabin an inter-event quantity. 1628ea272257SMauro Carvalho Chehab 1629ea272257SMauro Carvalho ChehabAn example of a histogram that combines data from other histograms 1630ea272257SMauro Carvalho Chehabinto a useful chain would be a 'wakeupswitch latency' histogram that 1631ea272257SMauro Carvalho Chehabcombines a 'wakeup latency' histogram and a 'switch latency' 1632ea272257SMauro Carvalho Chehabhistogram. 1633ea272257SMauro Carvalho Chehab 1634ea272257SMauro Carvalho ChehabNormally, a hist trigger specification consists of a (possibly 1635ea272257SMauro Carvalho Chehabcompound) key along with one or more numeric values, which are 1636ea272257SMauro Carvalho Chehabcontinually updated sums associated with that key. A histogram 1637ea272257SMauro Carvalho Chehabspecification in this case consists of individual key and value 1638ea272257SMauro Carvalho Chehabspecifications that refer to trace event fields associated with a 1639ea272257SMauro Carvalho Chehabsingle event type. 1640ea272257SMauro Carvalho Chehab 1641ea272257SMauro Carvalho ChehabThe inter-event hist trigger extension allows fields from multiple 1642ea272257SMauro Carvalho Chehabevents to be referenced and combined into a multi-event histogram 1643ea272257SMauro Carvalho Chehabspecification. In support of this overall goal, a few enabling 1644ea272257SMauro Carvalho Chehabfeatures have been added to the hist trigger support: 1645ea272257SMauro Carvalho Chehab 1646ea272257SMauro Carvalho Chehab - In order to compute an inter-event quantity, a value from one 1647ea272257SMauro Carvalho Chehab event needs to saved and then referenced from another event. This 1648ea272257SMauro Carvalho Chehab requires the introduction of support for histogram 'variables'. 1649ea272257SMauro Carvalho Chehab 1650ea272257SMauro Carvalho Chehab - The computation of inter-event quantities and their combination 1651ea272257SMauro Carvalho Chehab require some minimal amount of support for applying simple 1652ea272257SMauro Carvalho Chehab expressions to variables (+ and -). 1653ea272257SMauro Carvalho Chehab 1654ea272257SMauro Carvalho Chehab - A histogram consisting of inter-event quantities isn't logically a 1655ea272257SMauro Carvalho Chehab histogram on either event (so having the 'hist' file for either 1656ea272257SMauro Carvalho Chehab event host the histogram output doesn't really make sense). To 1657ea272257SMauro Carvalho Chehab address the idea that the histogram is associated with a 1658ea272257SMauro Carvalho Chehab combination of events, support is added allowing the creation of 1659ea272257SMauro Carvalho Chehab 'synthetic' events that are events derived from other events. 1660ea272257SMauro Carvalho Chehab These synthetic events are full-fledged events just like any other 1661ea272257SMauro Carvalho Chehab and can be used as such, as for instance to create the 1662ea272257SMauro Carvalho Chehab 'combination' histograms mentioned previously. 1663ea272257SMauro Carvalho Chehab 1664ea272257SMauro Carvalho Chehab - A set of 'actions' can be associated with histogram entries - 1665ea272257SMauro Carvalho Chehab these can be used to generate the previously mentioned synthetic 1666ea272257SMauro Carvalho Chehab events, but can also be used for other purposes, such as for 1667ea272257SMauro Carvalho Chehab example saving context when a 'max' latency has been hit. 1668ea272257SMauro Carvalho Chehab 1669ea272257SMauro Carvalho Chehab - Trace events don't have a 'timestamp' associated with them, but 1670ea272257SMauro Carvalho Chehab there is an implicit timestamp saved along with an event in the 1671ea272257SMauro Carvalho Chehab underlying ftrace ring buffer. This timestamp is now exposed as a 1672ea272257SMauro Carvalho Chehab a synthetic field named 'common_timestamp' which can be used in 1673ea272257SMauro Carvalho Chehab histograms as if it were any other event field; it isn't an actual 1674ea272257SMauro Carvalho Chehab field in the trace format but rather is a synthesized value that 1675ea272257SMauro Carvalho Chehab nonetheless can be used as if it were an actual field. By default 1676ea272257SMauro Carvalho Chehab it is in units of nanoseconds; appending '.usecs' to a 1677ea272257SMauro Carvalho Chehab common_timestamp field changes the units to microseconds. 1678ea272257SMauro Carvalho Chehab 1679ea272257SMauro Carvalho ChehabA note on inter-event timestamps: If common_timestamp is used in a 1680ea272257SMauro Carvalho Chehabhistogram, the trace buffer is automatically switched over to using 1681ea272257SMauro Carvalho Chehababsolute timestamps and the "global" trace clock, in order to avoid 1682ea272257SMauro Carvalho Chehabbogus timestamp differences with other clocks that aren't coherent 1683ea272257SMauro Carvalho Chehabacross CPUs. This can be overridden by specifying one of the other 1684ea272257SMauro Carvalho Chehabtrace clocks instead, using the "clock=XXX" hist trigger attribute, 1685ea272257SMauro Carvalho Chehabwhere XXX is any of the clocks listed in the tracing/trace_clock 1686ea272257SMauro Carvalho Chehabpseudo-file. 1687ea272257SMauro Carvalho Chehab 1688ea272257SMauro Carvalho ChehabThese features are described in more detail in the following sections. 1689ea272257SMauro Carvalho Chehab 1690ea272257SMauro Carvalho Chehab2.2.1 Histogram Variables 1691ea272257SMauro Carvalho Chehab------------------------- 1692ea272257SMauro Carvalho Chehab 1693ea272257SMauro Carvalho ChehabVariables are simply named locations used for saving and retrieving 1694ea272257SMauro Carvalho Chehabvalues between matching events. A 'matching' event is defined as an 1695ea272257SMauro Carvalho Chehabevent that has a matching key - if a variable is saved for a histogram 1696ea272257SMauro Carvalho Chehabentry corresponding to that key, any subsequent event with a matching 1697ea272257SMauro Carvalho Chehabkey can access that variable. 1698ea272257SMauro Carvalho Chehab 1699ea272257SMauro Carvalho ChehabA variable's value is normally available to any subsequent event until 1700ea272257SMauro Carvalho Chehabit is set to something else by a subsequent event. The one exception 1701ea272257SMauro Carvalho Chehabto that rule is that any variable used in an expression is essentially 1702ea272257SMauro Carvalho Chehab'read-once' - once it's used by an expression in a subsequent event, 1703ea272257SMauro Carvalho Chehabit's reset to its 'unset' state, which means it can't be used again 1704ea272257SMauro Carvalho Chehabunless it's set again. This ensures not only that an event doesn't 1705ea272257SMauro Carvalho Chehabuse an uninitialized variable in a calculation, but that that variable 1706ea272257SMauro Carvalho Chehabis used only once and not for any unrelated subsequent match. 1707ea272257SMauro Carvalho Chehab 1708ea272257SMauro Carvalho ChehabThe basic syntax for saving a variable is to simply prefix a unique 1709ea272257SMauro Carvalho Chehabvariable name not corresponding to any keyword along with an '=' sign 1710ea272257SMauro Carvalho Chehabto any event field. 1711ea272257SMauro Carvalho Chehab 1712ea272257SMauro Carvalho ChehabEither keys or values can be saved and retrieved in this way. This 1713ea272257SMauro Carvalho Chehabcreates a variable named 'ts0' for a histogram entry with the key 1714ea272257SMauro Carvalho Chehab'next_pid':: 1715ea272257SMauro Carvalho Chehab 1716ea272257SMauro Carvalho Chehab # echo 'hist:keys=next_pid:vals=$ts0:ts0=common_timestamp ... >> \ 1717ea272257SMauro Carvalho Chehab event/trigger 1718ea272257SMauro Carvalho Chehab 1719ea272257SMauro Carvalho ChehabThe ts0 variable can be accessed by any subsequent event having the 1720ea272257SMauro Carvalho Chehabsame pid as 'next_pid'. 1721ea272257SMauro Carvalho Chehab 1722ea272257SMauro Carvalho ChehabVariable references are formed by prepending the variable name with 1723ea272257SMauro Carvalho Chehabthe '$' sign. Thus for example, the ts0 variable above would be 1724ea272257SMauro Carvalho Chehabreferenced as '$ts0' in expressions. 1725ea272257SMauro Carvalho Chehab 1726ea272257SMauro Carvalho ChehabBecause 'vals=' is used, the common_timestamp variable value above 1727ea272257SMauro Carvalho Chehabwill also be summed as a normal histogram value would (though for a 1728ea272257SMauro Carvalho Chehabtimestamp it makes little sense). 1729ea272257SMauro Carvalho Chehab 1730ea272257SMauro Carvalho ChehabThe below shows that a key value can also be saved in the same way:: 1731ea272257SMauro Carvalho Chehab 1732ea272257SMauro Carvalho Chehab # echo 'hist:timer_pid=common_pid:key=timer_pid ...' >> event/trigger 1733ea272257SMauro Carvalho Chehab 1734ea272257SMauro Carvalho ChehabIf a variable isn't a key variable or prefixed with 'vals=', the 1735ea272257SMauro Carvalho Chehabassociated event field will be saved in a variable but won't be summed 1736ea272257SMauro Carvalho Chehabas a value:: 1737ea272257SMauro Carvalho Chehab 1738ea272257SMauro Carvalho Chehab # echo 'hist:keys=next_pid:ts1=common_timestamp ...' >> event/trigger 1739ea272257SMauro Carvalho Chehab 1740ea272257SMauro Carvalho ChehabMultiple variables can be assigned at the same time. The below would 1741ea272257SMauro Carvalho Chehabresult in both ts0 and b being created as variables, with both 1742ea272257SMauro Carvalho Chehabcommon_timestamp and field1 additionally being summed as values:: 1743ea272257SMauro Carvalho Chehab 1744ea272257SMauro Carvalho Chehab # echo 'hist:keys=pid:vals=$ts0,$b:ts0=common_timestamp,b=field1 ...' >> \ 1745ea272257SMauro Carvalho Chehab event/trigger 1746ea272257SMauro Carvalho Chehab 1747ea272257SMauro Carvalho ChehabNote that variable assignments can appear either preceding or 1748ea272257SMauro Carvalho Chehabfollowing their use. The command below behaves identically to the 1749ea272257SMauro Carvalho Chehabcommand above:: 1750ea272257SMauro Carvalho Chehab 1751ea272257SMauro Carvalho Chehab # echo 'hist:keys=pid:ts0=common_timestamp,b=field1:vals=$ts0,$b ...' >> \ 1752ea272257SMauro Carvalho Chehab event/trigger 1753ea272257SMauro Carvalho Chehab 1754ea272257SMauro Carvalho ChehabAny number of variables not bound to a 'vals=' prefix can also be 1755ea272257SMauro Carvalho Chehabassigned by simply separating them with colons. Below is the same 1756ea272257SMauro Carvalho Chehabthing but without the values being summed in the histogram:: 1757ea272257SMauro Carvalho Chehab 1758ea272257SMauro Carvalho Chehab # echo 'hist:keys=pid:ts0=common_timestamp:b=field1 ...' >> event/trigger 1759ea272257SMauro Carvalho Chehab 1760ea272257SMauro Carvalho ChehabVariables set as above can be referenced and used in expressions on 1761ea272257SMauro Carvalho Chehabanother event. 1762ea272257SMauro Carvalho Chehab 1763ea272257SMauro Carvalho ChehabFor example, here's how a latency can be calculated:: 1764ea272257SMauro Carvalho Chehab 1765ea272257SMauro Carvalho Chehab # echo 'hist:keys=pid,prio:ts0=common_timestamp ...' >> event1/trigger 1766ea272257SMauro Carvalho Chehab # echo 'hist:keys=next_pid:wakeup_lat=common_timestamp-$ts0 ...' >> event2/trigger 1767ea272257SMauro Carvalho Chehab 1768aea74de4SMasanari IidaIn the first line above, the event's timestamp is saved into the 1769ea272257SMauro Carvalho Chehabvariable ts0. In the next line, ts0 is subtracted from the second 1770ea272257SMauro Carvalho Chehabevent's timestamp to produce the latency, which is then assigned into 1771ea272257SMauro Carvalho Chehabyet another variable, 'wakeup_lat'. The hist trigger below in turn 1772ea272257SMauro Carvalho Chehabmakes use of the wakeup_lat variable to compute a combined latency 1773ea272257SMauro Carvalho Chehabusing the same key and variable from yet another event:: 1774ea272257SMauro Carvalho Chehab 1775ea272257SMauro Carvalho Chehab # echo 'hist:key=pid:wakeupswitch_lat=$wakeup_lat+$switchtime_lat ...' >> event3/trigger 1776ea272257SMauro Carvalho Chehab 1777ea272257SMauro Carvalho Chehab2.2.2 Synthetic Events 1778ea272257SMauro Carvalho Chehab---------------------- 1779ea272257SMauro Carvalho Chehab 1780ea272257SMauro Carvalho ChehabSynthetic events are user-defined events generated from hist trigger 1781ea272257SMauro Carvalho Chehabvariables or fields associated with one or more other events. Their 1782ea272257SMauro Carvalho Chehabpurpose is to provide a mechanism for displaying data spanning 1783ea272257SMauro Carvalho Chehabmultiple events consistent with the existing and already familiar 1784ea272257SMauro Carvalho Chehabusage for normal events. 1785ea272257SMauro Carvalho Chehab 1786ea272257SMauro Carvalho ChehabTo define a synthetic event, the user writes a simple specification 1787ea272257SMauro Carvalho Chehabconsisting of the name of the new event along with one or more 1788ea272257SMauro Carvalho Chehabvariables and their types, which can be any valid field type, 1789ea272257SMauro Carvalho Chehabseparated by semicolons, to the tracing/synthetic_events file. 1790ea272257SMauro Carvalho Chehab 1791ea272257SMauro Carvalho ChehabFor instance, the following creates a new event named 'wakeup_latency' 1792ea272257SMauro Carvalho Chehabwith 3 fields: lat, pid, and prio. Each of those fields is simply a 1793ea272257SMauro Carvalho Chehabvariable reference to a variable on another event:: 1794ea272257SMauro Carvalho Chehab 1795ea272257SMauro Carvalho Chehab # echo 'wakeup_latency \ 1796ea272257SMauro Carvalho Chehab u64 lat; \ 1797ea272257SMauro Carvalho Chehab pid_t pid; \ 1798ea272257SMauro Carvalho Chehab int prio' >> \ 1799ea272257SMauro Carvalho Chehab /sys/kernel/debug/tracing/synthetic_events 1800ea272257SMauro Carvalho Chehab 1801ea272257SMauro Carvalho ChehabReading the tracing/synthetic_events file lists all the currently 1802ea272257SMauro Carvalho Chehabdefined synthetic events, in this case the event defined above:: 1803ea272257SMauro Carvalho Chehab 1804ea272257SMauro Carvalho Chehab # cat /sys/kernel/debug/tracing/synthetic_events 1805ea272257SMauro Carvalho Chehab wakeup_latency u64 lat; pid_t pid; int prio 1806ea272257SMauro Carvalho Chehab 1807ea272257SMauro Carvalho ChehabAn existing synthetic event definition can be removed by prepending 1808ea272257SMauro Carvalho Chehabthe command that defined it with a '!':: 1809ea272257SMauro Carvalho Chehab 1810ea272257SMauro Carvalho Chehab # echo '!wakeup_latency u64 lat pid_t pid int prio' >> \ 1811ea272257SMauro Carvalho Chehab /sys/kernel/debug/tracing/synthetic_events 1812ea272257SMauro Carvalho Chehab 1813ea272257SMauro Carvalho ChehabAt this point, there isn't yet an actual 'wakeup_latency' event 1814aea74de4SMasanari Iidainstantiated in the event subsystem - for this to happen, a 'hist 1815ea272257SMauro Carvalho Chehabtrigger action' needs to be instantiated and bound to actual fields 1816ea272257SMauro Carvalho Chehaband variables defined on other events (see Section 2.2.3 below on 1817ea272257SMauro Carvalho Chehabhow that is done using hist trigger 'onmatch' action). Once that is 1818ea272257SMauro Carvalho Chehabdone, the 'wakeup_latency' synthetic event instance is created. 1819ea272257SMauro Carvalho Chehab 1820ea272257SMauro Carvalho ChehabA histogram can now be defined for the new synthetic event:: 1821ea272257SMauro Carvalho Chehab 1822ea272257SMauro Carvalho Chehab # echo 'hist:keys=pid,prio,lat.log2:sort=pid,lat' >> \ 1823ea272257SMauro Carvalho Chehab /sys/kernel/debug/tracing/events/synthetic/wakeup_latency/trigger 1824ea272257SMauro Carvalho Chehab 1825ea272257SMauro Carvalho ChehabThe new event is created under the tracing/events/synthetic/ directory 1826ea272257SMauro Carvalho Chehaband looks and behaves just like any other event:: 1827ea272257SMauro Carvalho Chehab 1828ea272257SMauro Carvalho Chehab # ls /sys/kernel/debug/tracing/events/synthetic/wakeup_latency 1829ea272257SMauro Carvalho Chehab enable filter format hist id trigger 1830ea272257SMauro Carvalho Chehab 1831ea272257SMauro Carvalho ChehabLike any other event, once a histogram is enabled for the event, the 1832ea272257SMauro Carvalho Chehaboutput can be displayed by reading the event's 'hist' file. 1833ea272257SMauro Carvalho Chehab 1834ea272257SMauro Carvalho Chehab2.2.3 Hist trigger 'actions' 1835ea272257SMauro Carvalho Chehab---------------------------- 1836ea272257SMauro Carvalho Chehab 1837ea272257SMauro Carvalho ChehabA hist trigger 'action' is a function that's executed whenever a 1838ea272257SMauro Carvalho Chehabhistogram entry is added or updated. 1839ea272257SMauro Carvalho Chehab 1840aea74de4SMasanari IidaThe default 'action' if no special function is explicitly specified is 1841ea272257SMauro Carvalho Chehabas it always has been, to simply update the set of values associated 1842ea272257SMauro Carvalho Chehabwith an entry. Some applications, however, may want to perform 1843ea272257SMauro Carvalho Chehabadditional actions at that point, such as generate another event, or 1844ea272257SMauro Carvalho Chehabcompare and save a maximum. 1845ea272257SMauro Carvalho Chehab 1846ea272257SMauro Carvalho ChehabThe following additional actions are available. To specify an action 1847ea272257SMauro Carvalho Chehabfor a given event, simply specify the action between colons in the 1848ea272257SMauro Carvalho Chehabhist trigger specification. 1849ea272257SMauro Carvalho Chehab 1850ea272257SMauro Carvalho Chehab - onmatch(matching.event).<synthetic_event_name>(param list) 1851ea272257SMauro Carvalho Chehab 1852ea272257SMauro Carvalho Chehab The 'onmatch(matching.event).<synthetic_event_name>(params)' hist 1853ea272257SMauro Carvalho Chehab trigger action is invoked whenever an event matches and the 1854ea272257SMauro Carvalho Chehab histogram entry would be added or updated. It causes the named 1855ea272257SMauro Carvalho Chehab synthetic event to be generated with the values given in the 1856ea272257SMauro Carvalho Chehab 'param list'. The result is the generation of a synthetic event 1857ea272257SMauro Carvalho Chehab that consists of the values contained in those variables at the 1858ea272257SMauro Carvalho Chehab time the invoking event was hit. 1859ea272257SMauro Carvalho Chehab 1860ea272257SMauro Carvalho Chehab The 'param list' consists of one or more parameters which may be 1861ea272257SMauro Carvalho Chehab either variables or fields defined on either the 'matching.event' 1862ea272257SMauro Carvalho Chehab or the target event. The variables or fields specified in the 1863ea272257SMauro Carvalho Chehab param list may be either fully-qualified or unqualified. If a 1864ea272257SMauro Carvalho Chehab variable is specified as unqualified, it must be unique between 1865ea272257SMauro Carvalho Chehab the two events. A field name used as a param can be unqualified 1866ea272257SMauro Carvalho Chehab if it refers to the target event, but must be fully qualified if 1867ea272257SMauro Carvalho Chehab it refers to the matching event. A fully-qualified name is of the 1868ea272257SMauro Carvalho Chehab form 'system.event_name.$var_name' or 'system.event_name.field'. 1869ea272257SMauro Carvalho Chehab 1870ea272257SMauro Carvalho Chehab The 'matching.event' specification is simply the fully qualified 1871ea272257SMauro Carvalho Chehab event name of the event that matches the target event for the 1872ea272257SMauro Carvalho Chehab onmatch() functionality, in the form 'system.event_name'. 1873ea272257SMauro Carvalho Chehab 1874ea272257SMauro Carvalho Chehab Finally, the number and type of variables/fields in the 'param 1875ea272257SMauro Carvalho Chehab list' must match the number and types of the fields in the 1876ea272257SMauro Carvalho Chehab synthetic event being generated. 1877ea272257SMauro Carvalho Chehab 1878ea272257SMauro Carvalho Chehab As an example the below defines a simple synthetic event and uses 1879ea272257SMauro Carvalho Chehab a variable defined on the sched_wakeup_new event as a parameter 1880ea272257SMauro Carvalho Chehab when invoking the synthetic event. Here we define the synthetic 1881ea272257SMauro Carvalho Chehab event:: 1882ea272257SMauro Carvalho Chehab 1883ea272257SMauro Carvalho Chehab # echo 'wakeup_new_test pid_t pid' >> \ 1884ea272257SMauro Carvalho Chehab /sys/kernel/debug/tracing/synthetic_events 1885ea272257SMauro Carvalho Chehab 1886ea272257SMauro Carvalho Chehab # cat /sys/kernel/debug/tracing/synthetic_events 1887ea272257SMauro Carvalho Chehab wakeup_new_test pid_t pid 1888ea272257SMauro Carvalho Chehab 1889ea272257SMauro Carvalho Chehab The following hist trigger both defines the missing testpid 1890ea272257SMauro Carvalho Chehab variable and specifies an onmatch() action that generates a 1891ea272257SMauro Carvalho Chehab wakeup_new_test synthetic event whenever a sched_wakeup_new event 1892ea272257SMauro Carvalho Chehab occurs, which because of the 'if comm == "cyclictest"' filter only 1893ea272257SMauro Carvalho Chehab happens when the executable is cyclictest:: 1894ea272257SMauro Carvalho Chehab 1895ea272257SMauro Carvalho Chehab # echo 'hist:keys=$testpid:testpid=pid:onmatch(sched.sched_wakeup_new).\ 1896ea272257SMauro Carvalho Chehab wakeup_new_test($testpid) if comm=="cyclictest"' >> \ 1897ea272257SMauro Carvalho Chehab /sys/kernel/debug/tracing/events/sched/sched_wakeup_new/trigger 1898ea272257SMauro Carvalho Chehab 1899ea272257SMauro Carvalho Chehab Creating and displaying a histogram based on those events is now 1900ea272257SMauro Carvalho Chehab just a matter of using the fields and new synthetic event in the 1901ea272257SMauro Carvalho Chehab tracing/events/synthetic directory, as usual:: 1902ea272257SMauro Carvalho Chehab 1903ea272257SMauro Carvalho Chehab # echo 'hist:keys=pid:sort=pid' >> \ 1904ea272257SMauro Carvalho Chehab /sys/kernel/debug/tracing/events/synthetic/wakeup_new_test/trigger 1905ea272257SMauro Carvalho Chehab 1906ea272257SMauro Carvalho Chehab Running 'cyclictest' should cause wakeup_new events to generate 1907ea272257SMauro Carvalho Chehab wakeup_new_test synthetic events which should result in histogram 1908ea272257SMauro Carvalho Chehab output in the wakeup_new_test event's hist file:: 1909ea272257SMauro Carvalho Chehab 1910ea272257SMauro Carvalho Chehab # cat /sys/kernel/debug/tracing/events/synthetic/wakeup_new_test/hist 1911ea272257SMauro Carvalho Chehab 1912ea272257SMauro Carvalho Chehab A more typical usage would be to use two events to calculate a 1913ea272257SMauro Carvalho Chehab latency. The following example uses a set of hist triggers to 1914ea272257SMauro Carvalho Chehab produce a 'wakeup_latency' histogram. 1915ea272257SMauro Carvalho Chehab 1916ea272257SMauro Carvalho Chehab First, we define a 'wakeup_latency' synthetic event:: 1917ea272257SMauro Carvalho Chehab 1918ea272257SMauro Carvalho Chehab # echo 'wakeup_latency u64 lat; pid_t pid; int prio' >> \ 1919ea272257SMauro Carvalho Chehab /sys/kernel/debug/tracing/synthetic_events 1920ea272257SMauro Carvalho Chehab 1921ea272257SMauro Carvalho Chehab Next, we specify that whenever we see a sched_waking event for a 1922ea272257SMauro Carvalho Chehab cyclictest thread, save the timestamp in a 'ts0' variable:: 1923ea272257SMauro Carvalho Chehab 1924ea272257SMauro Carvalho Chehab # echo 'hist:keys=$saved_pid:saved_pid=pid:ts0=common_timestamp.usecs \ 1925ea272257SMauro Carvalho Chehab if comm=="cyclictest"' >> \ 1926ea272257SMauro Carvalho Chehab /sys/kernel/debug/tracing/events/sched/sched_waking/trigger 1927ea272257SMauro Carvalho Chehab 1928ea272257SMauro Carvalho Chehab Then, when the corresponding thread is actually scheduled onto the 1929ea272257SMauro Carvalho Chehab CPU by a sched_switch event, calculate the latency and use that 1930ea272257SMauro Carvalho Chehab along with another variable and an event field to generate a 1931ea272257SMauro Carvalho Chehab wakeup_latency synthetic event:: 1932ea272257SMauro Carvalho Chehab 1933ea272257SMauro Carvalho Chehab # echo 'hist:keys=next_pid:wakeup_lat=common_timestamp.usecs-$ts0:\ 1934ea272257SMauro Carvalho Chehab onmatch(sched.sched_waking).wakeup_latency($wakeup_lat,\ 1935ea272257SMauro Carvalho Chehab $saved_pid,next_prio) if next_comm=="cyclictest"' >> \ 1936ea272257SMauro Carvalho Chehab /sys/kernel/debug/tracing/events/sched/sched_switch/trigger 1937ea272257SMauro Carvalho Chehab 1938ea272257SMauro Carvalho Chehab We also need to create a histogram on the wakeup_latency synthetic 1939ea272257SMauro Carvalho Chehab event in order to aggregate the generated synthetic event data:: 1940ea272257SMauro Carvalho Chehab 1941ea272257SMauro Carvalho Chehab # echo 'hist:keys=pid,prio,lat:sort=pid,lat' >> \ 1942ea272257SMauro Carvalho Chehab /sys/kernel/debug/tracing/events/synthetic/wakeup_latency/trigger 1943ea272257SMauro Carvalho Chehab 1944ea272257SMauro Carvalho Chehab Finally, once we've run cyclictest to actually generate some 1945ea272257SMauro Carvalho Chehab events, we can see the output by looking at the wakeup_latency 1946ea272257SMauro Carvalho Chehab synthetic event's hist file:: 1947ea272257SMauro Carvalho Chehab 1948ea272257SMauro Carvalho Chehab # cat /sys/kernel/debug/tracing/events/synthetic/wakeup_latency/hist 1949ea272257SMauro Carvalho Chehab 1950ea272257SMauro Carvalho Chehab - onmax(var).save(field,.. .) 1951ea272257SMauro Carvalho Chehab 1952ea272257SMauro Carvalho Chehab The 'onmax(var).save(field,...)' hist trigger action is invoked 1953ea272257SMauro Carvalho Chehab whenever the value of 'var' associated with a histogram entry 1954ea272257SMauro Carvalho Chehab exceeds the current maximum contained in that variable. 1955ea272257SMauro Carvalho Chehab 1956ea272257SMauro Carvalho Chehab The end result is that the trace event fields specified as the 1957ea272257SMauro Carvalho Chehab onmax.save() params will be saved if 'var' exceeds the current 1958ea272257SMauro Carvalho Chehab maximum for that hist trigger entry. This allows context from the 1959ea272257SMauro Carvalho Chehab event that exhibited the new maximum to be saved for later 1960ea272257SMauro Carvalho Chehab reference. When the histogram is displayed, additional fields 1961ea272257SMauro Carvalho Chehab displaying the saved values will be printed. 1962ea272257SMauro Carvalho Chehab 1963ea272257SMauro Carvalho Chehab As an example the below defines a couple of hist triggers, one for 1964ea272257SMauro Carvalho Chehab sched_waking and another for sched_switch, keyed on pid. Whenever 1965ea272257SMauro Carvalho Chehab a sched_waking occurs, the timestamp is saved in the entry 1966ea272257SMauro Carvalho Chehab corresponding to the current pid, and when the scheduler switches 1967ea272257SMauro Carvalho Chehab back to that pid, the timestamp difference is calculated. If the 1968ea272257SMauro Carvalho Chehab resulting latency, stored in wakeup_lat, exceeds the current 1969ea272257SMauro Carvalho Chehab maximum latency, the values specified in the save() fields are 1970ea272257SMauro Carvalho Chehab recorded:: 1971ea272257SMauro Carvalho Chehab 1972ea272257SMauro Carvalho Chehab # echo 'hist:keys=pid:ts0=common_timestamp.usecs \ 1973ea272257SMauro Carvalho Chehab if comm=="cyclictest"' >> \ 1974ea272257SMauro Carvalho Chehab /sys/kernel/debug/tracing/events/sched/sched_waking/trigger 1975ea272257SMauro Carvalho Chehab 1976ea272257SMauro Carvalho Chehab # echo 'hist:keys=next_pid:\ 1977ea272257SMauro Carvalho Chehab wakeup_lat=common_timestamp.usecs-$ts0:\ 1978ea272257SMauro Carvalho Chehab onmax($wakeup_lat).save(next_comm,prev_pid,prev_prio,prev_comm) \ 1979ea272257SMauro Carvalho Chehab if next_comm=="cyclictest"' >> \ 1980ea272257SMauro Carvalho Chehab /sys/kernel/debug/tracing/events/sched/sched_switch/trigger 1981ea272257SMauro Carvalho Chehab 1982ea272257SMauro Carvalho Chehab When the histogram is displayed, the max value and the saved 1983ea272257SMauro Carvalho Chehab values corresponding to the max are displayed following the rest 1984ea272257SMauro Carvalho Chehab of the fields:: 1985ea272257SMauro Carvalho Chehab 1986ea272257SMauro Carvalho Chehab # cat /sys/kernel/debug/tracing/events/sched/sched_switch/hist 1987ea272257SMauro Carvalho Chehab { next_pid: 2255 } hitcount: 239 1988ea272257SMauro Carvalho Chehab common_timestamp-ts0: 0 1989ea272257SMauro Carvalho Chehab max: 27 1990ea272257SMauro Carvalho Chehab next_comm: cyclictest 1991ea272257SMauro Carvalho Chehab prev_pid: 0 prev_prio: 120 prev_comm: swapper/1 1992ea272257SMauro Carvalho Chehab 1993ea272257SMauro Carvalho Chehab { next_pid: 2256 } hitcount: 2355 1994ea272257SMauro Carvalho Chehab common_timestamp-ts0: 0 1995ea272257SMauro Carvalho Chehab max: 49 next_comm: cyclictest 1996ea272257SMauro Carvalho Chehab prev_pid: 0 prev_prio: 120 prev_comm: swapper/0 1997ea272257SMauro Carvalho Chehab 1998ea272257SMauro Carvalho Chehab Totals: 1999ea272257SMauro Carvalho Chehab Hits: 12970 2000ea272257SMauro Carvalho Chehab Entries: 2 2001ea272257SMauro Carvalho Chehab Dropped: 0 2002ea272257SMauro Carvalho Chehab 2003ea272257SMauro Carvalho Chehab3. User space creating a trigger 2004ea272257SMauro Carvalho Chehab-------------------------------- 2005ea272257SMauro Carvalho Chehab 2006ea272257SMauro Carvalho ChehabWriting into /sys/kernel/tracing/trace_marker writes into the ftrace 2007ea272257SMauro Carvalho Chehabring buffer. This can also act like an event, by writing into the trigger 2008ea272257SMauro Carvalho Chehabfile located in /sys/kernel/tracing/events/ftrace/print/ 2009ea272257SMauro Carvalho Chehab 2010ea272257SMauro Carvalho ChehabModifying cyclictest to write into the trace_marker file before it sleeps 2011ea272257SMauro Carvalho Chehaband after it wakes up, something like this:: 2012ea272257SMauro Carvalho Chehab 2013ea272257SMauro Carvalho Chehab static void traceputs(char *str) 2014ea272257SMauro Carvalho Chehab { 2015ea272257SMauro Carvalho Chehab /* tracemark_fd is the trace_marker file descriptor */ 2016ea272257SMauro Carvalho Chehab if (tracemark_fd < 0) 2017ea272257SMauro Carvalho Chehab return; 2018ea272257SMauro Carvalho Chehab /* write the tracemark message */ 2019ea272257SMauro Carvalho Chehab write(tracemark_fd, str, strlen(str)); 2020ea272257SMauro Carvalho Chehab } 2021ea272257SMauro Carvalho Chehab 2022ea272257SMauro Carvalho ChehabAnd later add something like:: 2023ea272257SMauro Carvalho Chehab 2024ea272257SMauro Carvalho Chehab traceputs("start"); 2025ea272257SMauro Carvalho Chehab clock_nanosleep(...); 2026ea272257SMauro Carvalho Chehab traceputs("end"); 2027ea272257SMauro Carvalho Chehab 2028ea272257SMauro Carvalho ChehabWe can make a histogram from this:: 2029ea272257SMauro Carvalho Chehab 2030ea272257SMauro Carvalho Chehab # cd /sys/kernel/tracing 2031ea272257SMauro Carvalho Chehab # echo 'latency u64 lat' > synthetic_events 2032ea272257SMauro Carvalho Chehab # echo 'hist:keys=common_pid:ts0=common_timestamp.usecs if buf == "start"' > events/ftrace/print/trigger 2033ea272257SMauro Carvalho Chehab # echo 'hist:keys=common_pid:lat=common_timestamp.usecs-$ts0:onmatch(ftrace.print).latency($lat) if buf == "end"' >> events/ftrace/print/trigger 2034ea272257SMauro Carvalho Chehab # echo 'hist:keys=lat,common_pid:sort=lat' > events/synthetic/latency/trigger 2035ea272257SMauro Carvalho Chehab 2036ea272257SMauro Carvalho ChehabThe above created a synthetic event called "latency" and two histograms 2037ea272257SMauro Carvalho Chehabagainst the trace_marker, one gets triggered when "start" is written into the 2038ea272257SMauro Carvalho Chehabtrace_marker file and the other when "end" is written. If the pids match, then 2039ea272257SMauro Carvalho Chehabit will call the "latency" synthetic event with the calculated latency as its 2040ea272257SMauro Carvalho Chehabparameter. Finally, a histogram is added to the latency synthetic event to 2041ea272257SMauro Carvalho Chehabrecord the calculated latency along with the pid. 2042ea272257SMauro Carvalho Chehab 2043ea272257SMauro Carvalho ChehabNow running cyclictest with:: 2044ea272257SMauro Carvalho Chehab 2045ea272257SMauro Carvalho Chehab # ./cyclictest -p80 -d0 -i250 -n -a -t --tracemark -b 1000 2046ea272257SMauro Carvalho Chehab 2047ea272257SMauro Carvalho Chehab -p80 : run threads at priority 80 2048ea272257SMauro Carvalho Chehab -d0 : have all threads run at the same interval 2049ea272257SMauro Carvalho Chehab -i250 : start the interval at 250 microseconds (all threads will do this) 2050ea272257SMauro Carvalho Chehab -n : sleep with nanosleep 2051ea272257SMauro Carvalho Chehab -a : affine all threads to a separate CPU 2052ea272257SMauro Carvalho Chehab -t : one thread per available CPU 2053ea272257SMauro Carvalho Chehab --tracemark : enable trace mark writing 2054ea272257SMauro Carvalho Chehab -b 1000 : stop if any latency is greater than 1000 microseconds 2055ea272257SMauro Carvalho Chehab 2056ea272257SMauro Carvalho ChehabNote, the -b 1000 is used just to make --tracemark available. 2057ea272257SMauro Carvalho Chehab 2058ea272257SMauro Carvalho ChehabThen we can see the histogram created by this with:: 2059ea272257SMauro Carvalho Chehab 2060ea272257SMauro Carvalho Chehab # cat events/synthetic/latency/hist 2061ea272257SMauro Carvalho Chehab # event histogram 2062ea272257SMauro Carvalho Chehab # 2063ea272257SMauro Carvalho Chehab # trigger info: hist:keys=lat,common_pid:vals=hitcount:sort=lat:size=2048 [active] 2064ea272257SMauro Carvalho Chehab # 2065ea272257SMauro Carvalho Chehab 2066ea272257SMauro Carvalho Chehab { lat: 107, common_pid: 2039 } hitcount: 1 2067ea272257SMauro Carvalho Chehab { lat: 122, common_pid: 2041 } hitcount: 1 2068ea272257SMauro Carvalho Chehab { lat: 166, common_pid: 2039 } hitcount: 1 2069ea272257SMauro Carvalho Chehab { lat: 174, common_pid: 2039 } hitcount: 1 2070ea272257SMauro Carvalho Chehab { lat: 194, common_pid: 2041 } hitcount: 1 2071ea272257SMauro Carvalho Chehab { lat: 196, common_pid: 2036 } hitcount: 1 2072ea272257SMauro Carvalho Chehab { lat: 197, common_pid: 2038 } hitcount: 1 2073ea272257SMauro Carvalho Chehab { lat: 198, common_pid: 2039 } hitcount: 1 2074ea272257SMauro Carvalho Chehab { lat: 199, common_pid: 2039 } hitcount: 1 2075ea272257SMauro Carvalho Chehab { lat: 200, common_pid: 2041 } hitcount: 1 2076ea272257SMauro Carvalho Chehab { lat: 201, common_pid: 2039 } hitcount: 2 2077ea272257SMauro Carvalho Chehab { lat: 202, common_pid: 2038 } hitcount: 1 2078ea272257SMauro Carvalho Chehab { lat: 202, common_pid: 2043 } hitcount: 1 2079ea272257SMauro Carvalho Chehab { lat: 203, common_pid: 2039 } hitcount: 1 2080ea272257SMauro Carvalho Chehab { lat: 203, common_pid: 2036 } hitcount: 1 2081ea272257SMauro Carvalho Chehab { lat: 203, common_pid: 2041 } hitcount: 1 2082ea272257SMauro Carvalho Chehab { lat: 206, common_pid: 2038 } hitcount: 2 2083ea272257SMauro Carvalho Chehab { lat: 207, common_pid: 2039 } hitcount: 1 2084ea272257SMauro Carvalho Chehab { lat: 207, common_pid: 2036 } hitcount: 1 2085ea272257SMauro Carvalho Chehab { lat: 208, common_pid: 2040 } hitcount: 1 2086ea272257SMauro Carvalho Chehab { lat: 209, common_pid: 2043 } hitcount: 1 2087ea272257SMauro Carvalho Chehab { lat: 210, common_pid: 2039 } hitcount: 1 2088ea272257SMauro Carvalho Chehab { lat: 211, common_pid: 2039 } hitcount: 4 2089ea272257SMauro Carvalho Chehab { lat: 212, common_pid: 2043 } hitcount: 1 2090ea272257SMauro Carvalho Chehab { lat: 212, common_pid: 2039 } hitcount: 2 2091ea272257SMauro Carvalho Chehab { lat: 213, common_pid: 2039 } hitcount: 1 2092ea272257SMauro Carvalho Chehab { lat: 214, common_pid: 2038 } hitcount: 1 2093ea272257SMauro Carvalho Chehab { lat: 214, common_pid: 2039 } hitcount: 2 2094ea272257SMauro Carvalho Chehab { lat: 214, common_pid: 2042 } hitcount: 1 2095ea272257SMauro Carvalho Chehab { lat: 215, common_pid: 2039 } hitcount: 1 2096ea272257SMauro Carvalho Chehab { lat: 217, common_pid: 2036 } hitcount: 1 2097ea272257SMauro Carvalho Chehab { lat: 217, common_pid: 2040 } hitcount: 1 2098ea272257SMauro Carvalho Chehab { lat: 217, common_pid: 2039 } hitcount: 1 2099ea272257SMauro Carvalho Chehab { lat: 218, common_pid: 2039 } hitcount: 6 2100ea272257SMauro Carvalho Chehab { lat: 219, common_pid: 2039 } hitcount: 9 2101ea272257SMauro Carvalho Chehab { lat: 220, common_pid: 2039 } hitcount: 11 2102ea272257SMauro Carvalho Chehab { lat: 221, common_pid: 2039 } hitcount: 5 2103ea272257SMauro Carvalho Chehab { lat: 221, common_pid: 2042 } hitcount: 1 2104ea272257SMauro Carvalho Chehab { lat: 222, common_pid: 2039 } hitcount: 7 2105ea272257SMauro Carvalho Chehab { lat: 223, common_pid: 2036 } hitcount: 1 2106ea272257SMauro Carvalho Chehab { lat: 223, common_pid: 2039 } hitcount: 3 2107ea272257SMauro Carvalho Chehab { lat: 224, common_pid: 2039 } hitcount: 4 2108ea272257SMauro Carvalho Chehab { lat: 224, common_pid: 2037 } hitcount: 1 2109ea272257SMauro Carvalho Chehab { lat: 224, common_pid: 2036 } hitcount: 2 2110ea272257SMauro Carvalho Chehab { lat: 225, common_pid: 2039 } hitcount: 5 2111ea272257SMauro Carvalho Chehab { lat: 225, common_pid: 2042 } hitcount: 1 2112ea272257SMauro Carvalho Chehab { lat: 226, common_pid: 2039 } hitcount: 7 2113ea272257SMauro Carvalho Chehab { lat: 226, common_pid: 2036 } hitcount: 4 2114ea272257SMauro Carvalho Chehab { lat: 227, common_pid: 2039 } hitcount: 6 2115ea272257SMauro Carvalho Chehab { lat: 227, common_pid: 2036 } hitcount: 12 2116ea272257SMauro Carvalho Chehab { lat: 227, common_pid: 2043 } hitcount: 1 2117ea272257SMauro Carvalho Chehab { lat: 228, common_pid: 2039 } hitcount: 7 2118ea272257SMauro Carvalho Chehab { lat: 228, common_pid: 2036 } hitcount: 14 2119ea272257SMauro Carvalho Chehab { lat: 229, common_pid: 2039 } hitcount: 9 2120ea272257SMauro Carvalho Chehab { lat: 229, common_pid: 2036 } hitcount: 8 2121ea272257SMauro Carvalho Chehab { lat: 229, common_pid: 2038 } hitcount: 1 2122ea272257SMauro Carvalho Chehab { lat: 230, common_pid: 2039 } hitcount: 11 2123ea272257SMauro Carvalho Chehab { lat: 230, common_pid: 2036 } hitcount: 6 2124ea272257SMauro Carvalho Chehab { lat: 230, common_pid: 2043 } hitcount: 1 2125ea272257SMauro Carvalho Chehab { lat: 230, common_pid: 2042 } hitcount: 2 2126ea272257SMauro Carvalho Chehab { lat: 231, common_pid: 2041 } hitcount: 1 2127ea272257SMauro Carvalho Chehab { lat: 231, common_pid: 2036 } hitcount: 6 2128ea272257SMauro Carvalho Chehab { lat: 231, common_pid: 2043 } hitcount: 1 2129ea272257SMauro Carvalho Chehab { lat: 231, common_pid: 2039 } hitcount: 8 2130ea272257SMauro Carvalho Chehab { lat: 232, common_pid: 2037 } hitcount: 1 2131ea272257SMauro Carvalho Chehab { lat: 232, common_pid: 2039 } hitcount: 6 2132ea272257SMauro Carvalho Chehab { lat: 232, common_pid: 2040 } hitcount: 2 2133ea272257SMauro Carvalho Chehab { lat: 232, common_pid: 2036 } hitcount: 5 2134ea272257SMauro Carvalho Chehab { lat: 232, common_pid: 2043 } hitcount: 1 2135ea272257SMauro Carvalho Chehab { lat: 233, common_pid: 2036 } hitcount: 5 2136ea272257SMauro Carvalho Chehab { lat: 233, common_pid: 2039 } hitcount: 11 2137ea272257SMauro Carvalho Chehab { lat: 234, common_pid: 2039 } hitcount: 4 2138ea272257SMauro Carvalho Chehab { lat: 234, common_pid: 2038 } hitcount: 2 2139ea272257SMauro Carvalho Chehab { lat: 234, common_pid: 2043 } hitcount: 2 2140ea272257SMauro Carvalho Chehab { lat: 234, common_pid: 2036 } hitcount: 11 2141ea272257SMauro Carvalho Chehab { lat: 234, common_pid: 2040 } hitcount: 1 2142ea272257SMauro Carvalho Chehab { lat: 235, common_pid: 2037 } hitcount: 2 2143ea272257SMauro Carvalho Chehab { lat: 235, common_pid: 2036 } hitcount: 8 2144ea272257SMauro Carvalho Chehab { lat: 235, common_pid: 2043 } hitcount: 2 2145ea272257SMauro Carvalho Chehab { lat: 235, common_pid: 2039 } hitcount: 5 2146ea272257SMauro Carvalho Chehab { lat: 235, common_pid: 2042 } hitcount: 2 2147ea272257SMauro Carvalho Chehab { lat: 235, common_pid: 2040 } hitcount: 4 2148ea272257SMauro Carvalho Chehab { lat: 235, common_pid: 2041 } hitcount: 1 2149ea272257SMauro Carvalho Chehab { lat: 236, common_pid: 2036 } hitcount: 7 2150ea272257SMauro Carvalho Chehab { lat: 236, common_pid: 2037 } hitcount: 1 2151ea272257SMauro Carvalho Chehab { lat: 236, common_pid: 2041 } hitcount: 5 2152ea272257SMauro Carvalho Chehab { lat: 236, common_pid: 2039 } hitcount: 3 2153ea272257SMauro Carvalho Chehab { lat: 236, common_pid: 2043 } hitcount: 9 2154ea272257SMauro Carvalho Chehab { lat: 236, common_pid: 2040 } hitcount: 7 2155ea272257SMauro Carvalho Chehab { lat: 237, common_pid: 2037 } hitcount: 1 2156ea272257SMauro Carvalho Chehab { lat: 237, common_pid: 2040 } hitcount: 1 2157ea272257SMauro Carvalho Chehab { lat: 237, common_pid: 2036 } hitcount: 9 2158ea272257SMauro Carvalho Chehab { lat: 237, common_pid: 2039 } hitcount: 3 2159ea272257SMauro Carvalho Chehab { lat: 237, common_pid: 2043 } hitcount: 8 2160ea272257SMauro Carvalho Chehab { lat: 237, common_pid: 2042 } hitcount: 2 2161ea272257SMauro Carvalho Chehab { lat: 237, common_pid: 2041 } hitcount: 2 2162ea272257SMauro Carvalho Chehab { lat: 238, common_pid: 2043 } hitcount: 10 2163ea272257SMauro Carvalho Chehab { lat: 238, common_pid: 2040 } hitcount: 1 2164ea272257SMauro Carvalho Chehab { lat: 238, common_pid: 2037 } hitcount: 9 2165ea272257SMauro Carvalho Chehab { lat: 238, common_pid: 2038 } hitcount: 1 2166ea272257SMauro Carvalho Chehab { lat: 238, common_pid: 2039 } hitcount: 1 2167ea272257SMauro Carvalho Chehab { lat: 238, common_pid: 2042 } hitcount: 3 2168ea272257SMauro Carvalho Chehab { lat: 238, common_pid: 2036 } hitcount: 7 2169ea272257SMauro Carvalho Chehab { lat: 239, common_pid: 2041 } hitcount: 1 2170ea272257SMauro Carvalho Chehab { lat: 239, common_pid: 2043 } hitcount: 11 2171ea272257SMauro Carvalho Chehab { lat: 239, common_pid: 2037 } hitcount: 11 2172ea272257SMauro Carvalho Chehab { lat: 239, common_pid: 2038 } hitcount: 6 2173ea272257SMauro Carvalho Chehab { lat: 239, common_pid: 2036 } hitcount: 7 2174ea272257SMauro Carvalho Chehab { lat: 239, common_pid: 2040 } hitcount: 1 2175ea272257SMauro Carvalho Chehab { lat: 239, common_pid: 2042 } hitcount: 9 2176ea272257SMauro Carvalho Chehab { lat: 240, common_pid: 2037 } hitcount: 29 2177ea272257SMauro Carvalho Chehab { lat: 240, common_pid: 2043 } hitcount: 15 2178ea272257SMauro Carvalho Chehab { lat: 240, common_pid: 2040 } hitcount: 44 2179ea272257SMauro Carvalho Chehab { lat: 240, common_pid: 2039 } hitcount: 1 2180ea272257SMauro Carvalho Chehab { lat: 240, common_pid: 2041 } hitcount: 2 2181ea272257SMauro Carvalho Chehab { lat: 240, common_pid: 2038 } hitcount: 1 2182ea272257SMauro Carvalho Chehab { lat: 240, common_pid: 2036 } hitcount: 10 2183ea272257SMauro Carvalho Chehab { lat: 240, common_pid: 2042 } hitcount: 13 2184ea272257SMauro Carvalho Chehab { lat: 241, common_pid: 2036 } hitcount: 21 2185ea272257SMauro Carvalho Chehab { lat: 241, common_pid: 2041 } hitcount: 36 2186ea272257SMauro Carvalho Chehab { lat: 241, common_pid: 2037 } hitcount: 34 2187ea272257SMauro Carvalho Chehab { lat: 241, common_pid: 2042 } hitcount: 14 2188ea272257SMauro Carvalho Chehab { lat: 241, common_pid: 2040 } hitcount: 94 2189ea272257SMauro Carvalho Chehab { lat: 241, common_pid: 2039 } hitcount: 12 2190ea272257SMauro Carvalho Chehab { lat: 241, common_pid: 2038 } hitcount: 2 2191ea272257SMauro Carvalho Chehab { lat: 241, common_pid: 2043 } hitcount: 28 2192ea272257SMauro Carvalho Chehab { lat: 242, common_pid: 2040 } hitcount: 109 2193ea272257SMauro Carvalho Chehab { lat: 242, common_pid: 2041 } hitcount: 506 2194ea272257SMauro Carvalho Chehab { lat: 242, common_pid: 2039 } hitcount: 155 2195ea272257SMauro Carvalho Chehab { lat: 242, common_pid: 2042 } hitcount: 21 2196ea272257SMauro Carvalho Chehab { lat: 242, common_pid: 2037 } hitcount: 52 2197ea272257SMauro Carvalho Chehab { lat: 242, common_pid: 2043 } hitcount: 21 2198ea272257SMauro Carvalho Chehab { lat: 242, common_pid: 2036 } hitcount: 16 2199ea272257SMauro Carvalho Chehab { lat: 242, common_pid: 2038 } hitcount: 156 2200ea272257SMauro Carvalho Chehab { lat: 243, common_pid: 2037 } hitcount: 46 2201ea272257SMauro Carvalho Chehab { lat: 243, common_pid: 2039 } hitcount: 40 2202ea272257SMauro Carvalho Chehab { lat: 243, common_pid: 2042 } hitcount: 119 2203ea272257SMauro Carvalho Chehab { lat: 243, common_pid: 2041 } hitcount: 611 2204ea272257SMauro Carvalho Chehab { lat: 243, common_pid: 2036 } hitcount: 69 2205ea272257SMauro Carvalho Chehab { lat: 243, common_pid: 2038 } hitcount: 784 2206ea272257SMauro Carvalho Chehab { lat: 243, common_pid: 2040 } hitcount: 323 2207ea272257SMauro Carvalho Chehab { lat: 243, common_pid: 2043 } hitcount: 14 2208ea272257SMauro Carvalho Chehab { lat: 244, common_pid: 2043 } hitcount: 35 2209ea272257SMauro Carvalho Chehab { lat: 244, common_pid: 2042 } hitcount: 305 2210ea272257SMauro Carvalho Chehab { lat: 244, common_pid: 2039 } hitcount: 8 2211ea272257SMauro Carvalho Chehab { lat: 244, common_pid: 2040 } hitcount: 4515 2212ea272257SMauro Carvalho Chehab { lat: 244, common_pid: 2038 } hitcount: 371 2213ea272257SMauro Carvalho Chehab { lat: 244, common_pid: 2037 } hitcount: 31 2214ea272257SMauro Carvalho Chehab { lat: 244, common_pid: 2036 } hitcount: 114 2215ea272257SMauro Carvalho Chehab { lat: 244, common_pid: 2041 } hitcount: 3396 2216ea272257SMauro Carvalho Chehab { lat: 245, common_pid: 2036 } hitcount: 700 2217ea272257SMauro Carvalho Chehab { lat: 245, common_pid: 2041 } hitcount: 2772 2218ea272257SMauro Carvalho Chehab { lat: 245, common_pid: 2037 } hitcount: 268 2219ea272257SMauro Carvalho Chehab { lat: 245, common_pid: 2039 } hitcount: 472 2220ea272257SMauro Carvalho Chehab { lat: 245, common_pid: 2038 } hitcount: 2758 2221ea272257SMauro Carvalho Chehab { lat: 245, common_pid: 2042 } hitcount: 3833 2222ea272257SMauro Carvalho Chehab { lat: 245, common_pid: 2040 } hitcount: 3105 2223ea272257SMauro Carvalho Chehab { lat: 245, common_pid: 2043 } hitcount: 645 2224ea272257SMauro Carvalho Chehab { lat: 246, common_pid: 2038 } hitcount: 3451 2225ea272257SMauro Carvalho Chehab { lat: 246, common_pid: 2041 } hitcount: 142 2226ea272257SMauro Carvalho Chehab { lat: 246, common_pid: 2037 } hitcount: 5101 2227ea272257SMauro Carvalho Chehab { lat: 246, common_pid: 2040 } hitcount: 68 2228ea272257SMauro Carvalho Chehab { lat: 246, common_pid: 2043 } hitcount: 5099 2229ea272257SMauro Carvalho Chehab { lat: 246, common_pid: 2039 } hitcount: 5608 2230ea272257SMauro Carvalho Chehab { lat: 246, common_pid: 2042 } hitcount: 3723 2231ea272257SMauro Carvalho Chehab { lat: 246, common_pid: 2036 } hitcount: 4738 2232ea272257SMauro Carvalho Chehab { lat: 247, common_pid: 2042 } hitcount: 312 2233ea272257SMauro Carvalho Chehab { lat: 247, common_pid: 2043 } hitcount: 2385 2234ea272257SMauro Carvalho Chehab { lat: 247, common_pid: 2041 } hitcount: 452 2235ea272257SMauro Carvalho Chehab { lat: 247, common_pid: 2038 } hitcount: 792 2236ea272257SMauro Carvalho Chehab { lat: 247, common_pid: 2040 } hitcount: 78 2237ea272257SMauro Carvalho Chehab { lat: 247, common_pid: 2036 } hitcount: 2375 2238ea272257SMauro Carvalho Chehab { lat: 247, common_pid: 2039 } hitcount: 1834 2239ea272257SMauro Carvalho Chehab { lat: 247, common_pid: 2037 } hitcount: 2655 2240ea272257SMauro Carvalho Chehab { lat: 248, common_pid: 2037 } hitcount: 36 2241ea272257SMauro Carvalho Chehab { lat: 248, common_pid: 2042 } hitcount: 11 2242ea272257SMauro Carvalho Chehab { lat: 248, common_pid: 2038 } hitcount: 122 2243ea272257SMauro Carvalho Chehab { lat: 248, common_pid: 2036 } hitcount: 135 2244ea272257SMauro Carvalho Chehab { lat: 248, common_pid: 2039 } hitcount: 26 2245ea272257SMauro Carvalho Chehab { lat: 248, common_pid: 2041 } hitcount: 503 2246ea272257SMauro Carvalho Chehab { lat: 248, common_pid: 2043 } hitcount: 66 2247ea272257SMauro Carvalho Chehab { lat: 248, common_pid: 2040 } hitcount: 46 2248ea272257SMauro Carvalho Chehab { lat: 249, common_pid: 2037 } hitcount: 29 2249ea272257SMauro Carvalho Chehab { lat: 249, common_pid: 2038 } hitcount: 1 2250ea272257SMauro Carvalho Chehab { lat: 249, common_pid: 2043 } hitcount: 29 2251ea272257SMauro Carvalho Chehab { lat: 249, common_pid: 2039 } hitcount: 8 2252ea272257SMauro Carvalho Chehab { lat: 249, common_pid: 2042 } hitcount: 56 2253ea272257SMauro Carvalho Chehab { lat: 249, common_pid: 2040 } hitcount: 27 2254ea272257SMauro Carvalho Chehab { lat: 249, common_pid: 2041 } hitcount: 11 2255ea272257SMauro Carvalho Chehab { lat: 249, common_pid: 2036 } hitcount: 27 2256ea272257SMauro Carvalho Chehab { lat: 250, common_pid: 2038 } hitcount: 1 2257ea272257SMauro Carvalho Chehab { lat: 250, common_pid: 2036 } hitcount: 30 2258ea272257SMauro Carvalho Chehab { lat: 250, common_pid: 2040 } hitcount: 19 2259ea272257SMauro Carvalho Chehab { lat: 250, common_pid: 2043 } hitcount: 22 2260ea272257SMauro Carvalho Chehab { lat: 250, common_pid: 2042 } hitcount: 20 2261ea272257SMauro Carvalho Chehab { lat: 250, common_pid: 2041 } hitcount: 1 2262ea272257SMauro Carvalho Chehab { lat: 250, common_pid: 2039 } hitcount: 6 2263ea272257SMauro Carvalho Chehab { lat: 250, common_pid: 2037 } hitcount: 48 2264ea272257SMauro Carvalho Chehab { lat: 251, common_pid: 2037 } hitcount: 43 2265ea272257SMauro Carvalho Chehab { lat: 251, common_pid: 2039 } hitcount: 1 2266ea272257SMauro Carvalho Chehab { lat: 251, common_pid: 2036 } hitcount: 12 2267ea272257SMauro Carvalho Chehab { lat: 251, common_pid: 2042 } hitcount: 2 2268ea272257SMauro Carvalho Chehab { lat: 251, common_pid: 2041 } hitcount: 1 2269ea272257SMauro Carvalho Chehab { lat: 251, common_pid: 2043 } hitcount: 15 2270ea272257SMauro Carvalho Chehab { lat: 251, common_pid: 2040 } hitcount: 3 2271ea272257SMauro Carvalho Chehab { lat: 252, common_pid: 2040 } hitcount: 1 2272ea272257SMauro Carvalho Chehab { lat: 252, common_pid: 2036 } hitcount: 12 2273ea272257SMauro Carvalho Chehab { lat: 252, common_pid: 2037 } hitcount: 21 2274ea272257SMauro Carvalho Chehab { lat: 252, common_pid: 2043 } hitcount: 14 2275ea272257SMauro Carvalho Chehab { lat: 253, common_pid: 2037 } hitcount: 21 2276ea272257SMauro Carvalho Chehab { lat: 253, common_pid: 2039 } hitcount: 2 2277ea272257SMauro Carvalho Chehab { lat: 253, common_pid: 2036 } hitcount: 9 2278ea272257SMauro Carvalho Chehab { lat: 253, common_pid: 2043 } hitcount: 6 2279ea272257SMauro Carvalho Chehab { lat: 253, common_pid: 2040 } hitcount: 1 2280ea272257SMauro Carvalho Chehab { lat: 254, common_pid: 2036 } hitcount: 8 2281ea272257SMauro Carvalho Chehab { lat: 254, common_pid: 2043 } hitcount: 3 2282ea272257SMauro Carvalho Chehab { lat: 254, common_pid: 2041 } hitcount: 1 2283ea272257SMauro Carvalho Chehab { lat: 254, common_pid: 2042 } hitcount: 1 2284ea272257SMauro Carvalho Chehab { lat: 254, common_pid: 2039 } hitcount: 1 2285ea272257SMauro Carvalho Chehab { lat: 254, common_pid: 2037 } hitcount: 12 2286ea272257SMauro Carvalho Chehab { lat: 255, common_pid: 2043 } hitcount: 1 2287ea272257SMauro Carvalho Chehab { lat: 255, common_pid: 2037 } hitcount: 2 2288ea272257SMauro Carvalho Chehab { lat: 255, common_pid: 2036 } hitcount: 2 2289ea272257SMauro Carvalho Chehab { lat: 255, common_pid: 2039 } hitcount: 8 2290ea272257SMauro Carvalho Chehab { lat: 256, common_pid: 2043 } hitcount: 1 2291ea272257SMauro Carvalho Chehab { lat: 256, common_pid: 2036 } hitcount: 4 2292ea272257SMauro Carvalho Chehab { lat: 256, common_pid: 2039 } hitcount: 6 2293ea272257SMauro Carvalho Chehab { lat: 257, common_pid: 2039 } hitcount: 5 2294ea272257SMauro Carvalho Chehab { lat: 257, common_pid: 2036 } hitcount: 4 2295ea272257SMauro Carvalho Chehab { lat: 258, common_pid: 2039 } hitcount: 5 2296ea272257SMauro Carvalho Chehab { lat: 258, common_pid: 2036 } hitcount: 2 2297ea272257SMauro Carvalho Chehab { lat: 259, common_pid: 2036 } hitcount: 7 2298ea272257SMauro Carvalho Chehab { lat: 259, common_pid: 2039 } hitcount: 7 2299ea272257SMauro Carvalho Chehab { lat: 260, common_pid: 2036 } hitcount: 8 2300ea272257SMauro Carvalho Chehab { lat: 260, common_pid: 2039 } hitcount: 6 2301ea272257SMauro Carvalho Chehab { lat: 261, common_pid: 2036 } hitcount: 5 2302ea272257SMauro Carvalho Chehab { lat: 261, common_pid: 2039 } hitcount: 7 2303ea272257SMauro Carvalho Chehab { lat: 262, common_pid: 2039 } hitcount: 5 2304ea272257SMauro Carvalho Chehab { lat: 262, common_pid: 2036 } hitcount: 5 2305ea272257SMauro Carvalho Chehab { lat: 263, common_pid: 2039 } hitcount: 7 2306ea272257SMauro Carvalho Chehab { lat: 263, common_pid: 2036 } hitcount: 7 2307ea272257SMauro Carvalho Chehab { lat: 264, common_pid: 2039 } hitcount: 9 2308ea272257SMauro Carvalho Chehab { lat: 264, common_pid: 2036 } hitcount: 9 2309ea272257SMauro Carvalho Chehab { lat: 265, common_pid: 2036 } hitcount: 5 2310ea272257SMauro Carvalho Chehab { lat: 265, common_pid: 2039 } hitcount: 1 2311ea272257SMauro Carvalho Chehab { lat: 266, common_pid: 2036 } hitcount: 1 2312ea272257SMauro Carvalho Chehab { lat: 266, common_pid: 2039 } hitcount: 3 2313ea272257SMauro Carvalho Chehab { lat: 267, common_pid: 2036 } hitcount: 1 2314ea272257SMauro Carvalho Chehab { lat: 267, common_pid: 2039 } hitcount: 3 2315ea272257SMauro Carvalho Chehab { lat: 268, common_pid: 2036 } hitcount: 1 2316ea272257SMauro Carvalho Chehab { lat: 268, common_pid: 2039 } hitcount: 6 2317ea272257SMauro Carvalho Chehab { lat: 269, common_pid: 2036 } hitcount: 1 2318ea272257SMauro Carvalho Chehab { lat: 269, common_pid: 2043 } hitcount: 1 2319ea272257SMauro Carvalho Chehab { lat: 269, common_pid: 2039 } hitcount: 2 2320ea272257SMauro Carvalho Chehab { lat: 270, common_pid: 2040 } hitcount: 1 2321ea272257SMauro Carvalho Chehab { lat: 270, common_pid: 2039 } hitcount: 6 2322ea272257SMauro Carvalho Chehab { lat: 271, common_pid: 2041 } hitcount: 1 2323ea272257SMauro Carvalho Chehab { lat: 271, common_pid: 2039 } hitcount: 5 2324ea272257SMauro Carvalho Chehab { lat: 272, common_pid: 2039 } hitcount: 10 2325ea272257SMauro Carvalho Chehab { lat: 273, common_pid: 2039 } hitcount: 8 2326ea272257SMauro Carvalho Chehab { lat: 274, common_pid: 2039 } hitcount: 2 2327ea272257SMauro Carvalho Chehab { lat: 275, common_pid: 2039 } hitcount: 1 2328ea272257SMauro Carvalho Chehab { lat: 276, common_pid: 2039 } hitcount: 2 2329ea272257SMauro Carvalho Chehab { lat: 276, common_pid: 2037 } hitcount: 1 2330ea272257SMauro Carvalho Chehab { lat: 276, common_pid: 2038 } hitcount: 1 2331ea272257SMauro Carvalho Chehab { lat: 277, common_pid: 2039 } hitcount: 1 2332ea272257SMauro Carvalho Chehab { lat: 277, common_pid: 2042 } hitcount: 1 2333ea272257SMauro Carvalho Chehab { lat: 278, common_pid: 2039 } hitcount: 1 2334ea272257SMauro Carvalho Chehab { lat: 279, common_pid: 2039 } hitcount: 4 2335ea272257SMauro Carvalho Chehab { lat: 279, common_pid: 2043 } hitcount: 1 2336ea272257SMauro Carvalho Chehab { lat: 280, common_pid: 2039 } hitcount: 3 2337ea272257SMauro Carvalho Chehab { lat: 283, common_pid: 2036 } hitcount: 2 2338ea272257SMauro Carvalho Chehab { lat: 284, common_pid: 2039 } hitcount: 1 2339ea272257SMauro Carvalho Chehab { lat: 284, common_pid: 2043 } hitcount: 1 2340ea272257SMauro Carvalho Chehab { lat: 288, common_pid: 2039 } hitcount: 1 2341ea272257SMauro Carvalho Chehab { lat: 289, common_pid: 2039 } hitcount: 1 2342ea272257SMauro Carvalho Chehab { lat: 300, common_pid: 2039 } hitcount: 1 2343ea272257SMauro Carvalho Chehab { lat: 384, common_pid: 2039 } hitcount: 1 2344ea272257SMauro Carvalho Chehab 2345ea272257SMauro Carvalho Chehab Totals: 2346ea272257SMauro Carvalho Chehab Hits: 67625 2347ea272257SMauro Carvalho Chehab Entries: 278 2348ea272257SMauro Carvalho Chehab Dropped: 0 2349ea272257SMauro Carvalho Chehab 2350ea272257SMauro Carvalho ChehabNote, the writes are around the sleep, so ideally they will all be of 250 2351ea272257SMauro Carvalho Chehabmicroseconds. If you are wondering how there are several that are under 2352ea272257SMauro Carvalho Chehab250 microseconds, that is because the way cyclictest works, is if one 2353ea272257SMauro Carvalho Chehabiteration comes in late, the next one will set the timer to wake up less that 2354ea272257SMauro Carvalho Chehab250. That is, if an iteration came in 50 microseconds late, the next wake up 2355ea272257SMauro Carvalho Chehabwill be at 200 microseconds. 2356ea272257SMauro Carvalho Chehab 2357ea272257SMauro Carvalho ChehabBut this could easily be done in userspace. To make this even more 2358ea272257SMauro Carvalho Chehabinteresting, we can mix the histogram between events that happened in the 2359ea272257SMauro Carvalho Chehabkernel with trace_marker:: 2360ea272257SMauro Carvalho Chehab 2361ea272257SMauro Carvalho Chehab # cd /sys/kernel/tracing 2362ea272257SMauro Carvalho Chehab # echo 'latency u64 lat' > synthetic_events 2363ea272257SMauro Carvalho Chehab # echo 'hist:keys=pid:ts0=common_timestamp.usecs' > events/sched/sched_waking/trigger 2364ea272257SMauro Carvalho Chehab # echo 'hist:keys=common_pid:lat=common_timestamp.usecs-$ts0:onmatch(sched.sched_waking).latency($lat) if buf == "end"' > events/ftrace/print/trigger 2365ea272257SMauro Carvalho Chehab # echo 'hist:keys=lat,common_pid:sort=lat' > events/synthetic/latency/trigger 2366ea272257SMauro Carvalho Chehab 2367ea272257SMauro Carvalho ChehabThe difference this time is that instead of using the trace_marker to start 2368ea272257SMauro Carvalho Chehabthe latency, the sched_waking event is used, matching the common_pid for the 2369ea272257SMauro Carvalho Chehabtrace_marker write with the pid that is being woken by sched_waking. 2370ea272257SMauro Carvalho Chehab 2371ea272257SMauro Carvalho ChehabAfter running cyclictest again with the same parameters, we now have:: 2372ea272257SMauro Carvalho Chehab 2373ea272257SMauro Carvalho Chehab # cat events/synthetic/latency/hist 2374ea272257SMauro Carvalho Chehab # event histogram 2375ea272257SMauro Carvalho Chehab # 2376ea272257SMauro Carvalho Chehab # trigger info: hist:keys=lat,common_pid:vals=hitcount:sort=lat:size=2048 [active] 2377ea272257SMauro Carvalho Chehab # 2378ea272257SMauro Carvalho Chehab 2379ea272257SMauro Carvalho Chehab { lat: 7, common_pid: 2302 } hitcount: 640 2380ea272257SMauro Carvalho Chehab { lat: 7, common_pid: 2299 } hitcount: 42 2381ea272257SMauro Carvalho Chehab { lat: 7, common_pid: 2303 } hitcount: 18 2382ea272257SMauro Carvalho Chehab { lat: 7, common_pid: 2305 } hitcount: 166 2383ea272257SMauro Carvalho Chehab { lat: 7, common_pid: 2306 } hitcount: 1 2384ea272257SMauro Carvalho Chehab { lat: 7, common_pid: 2301 } hitcount: 91 2385ea272257SMauro Carvalho Chehab { lat: 7, common_pid: 2300 } hitcount: 17 2386ea272257SMauro Carvalho Chehab { lat: 8, common_pid: 2303 } hitcount: 8296 2387ea272257SMauro Carvalho Chehab { lat: 8, common_pid: 2304 } hitcount: 6864 2388ea272257SMauro Carvalho Chehab { lat: 8, common_pid: 2305 } hitcount: 9464 2389ea272257SMauro Carvalho Chehab { lat: 8, common_pid: 2301 } hitcount: 9213 2390ea272257SMauro Carvalho Chehab { lat: 8, common_pid: 2306 } hitcount: 6246 2391ea272257SMauro Carvalho Chehab { lat: 8, common_pid: 2302 } hitcount: 8797 2392ea272257SMauro Carvalho Chehab { lat: 8, common_pid: 2299 } hitcount: 8771 2393ea272257SMauro Carvalho Chehab { lat: 8, common_pid: 2300 } hitcount: 8119 2394ea272257SMauro Carvalho Chehab { lat: 9, common_pid: 2305 } hitcount: 1519 2395ea272257SMauro Carvalho Chehab { lat: 9, common_pid: 2299 } hitcount: 2346 2396ea272257SMauro Carvalho Chehab { lat: 9, common_pid: 2303 } hitcount: 2841 2397ea272257SMauro Carvalho Chehab { lat: 9, common_pid: 2301 } hitcount: 1846 2398ea272257SMauro Carvalho Chehab { lat: 9, common_pid: 2304 } hitcount: 3861 2399ea272257SMauro Carvalho Chehab { lat: 9, common_pid: 2302 } hitcount: 1210 2400ea272257SMauro Carvalho Chehab { lat: 9, common_pid: 2300 } hitcount: 2762 2401ea272257SMauro Carvalho Chehab { lat: 9, common_pid: 2306 } hitcount: 4247 2402ea272257SMauro Carvalho Chehab { lat: 10, common_pid: 2299 } hitcount: 16 2403ea272257SMauro Carvalho Chehab { lat: 10, common_pid: 2306 } hitcount: 333 2404ea272257SMauro Carvalho Chehab { lat: 10, common_pid: 2303 } hitcount: 16 2405ea272257SMauro Carvalho Chehab { lat: 10, common_pid: 2304 } hitcount: 168 2406ea272257SMauro Carvalho Chehab { lat: 10, common_pid: 2302 } hitcount: 240 2407ea272257SMauro Carvalho Chehab { lat: 10, common_pid: 2301 } hitcount: 28 2408ea272257SMauro Carvalho Chehab { lat: 10, common_pid: 2300 } hitcount: 95 2409ea272257SMauro Carvalho Chehab { lat: 10, common_pid: 2305 } hitcount: 18 2410ea272257SMauro Carvalho Chehab { lat: 11, common_pid: 2303 } hitcount: 5 2411ea272257SMauro Carvalho Chehab { lat: 11, common_pid: 2305 } hitcount: 8 2412ea272257SMauro Carvalho Chehab { lat: 11, common_pid: 2306 } hitcount: 221 2413ea272257SMauro Carvalho Chehab { lat: 11, common_pid: 2302 } hitcount: 76 2414ea272257SMauro Carvalho Chehab { lat: 11, common_pid: 2304 } hitcount: 26 2415ea272257SMauro Carvalho Chehab { lat: 11, common_pid: 2300 } hitcount: 125 2416ea272257SMauro Carvalho Chehab { lat: 11, common_pid: 2299 } hitcount: 2 2417ea272257SMauro Carvalho Chehab { lat: 12, common_pid: 2305 } hitcount: 3 2418ea272257SMauro Carvalho Chehab { lat: 12, common_pid: 2300 } hitcount: 6 2419ea272257SMauro Carvalho Chehab { lat: 12, common_pid: 2306 } hitcount: 90 2420ea272257SMauro Carvalho Chehab { lat: 12, common_pid: 2302 } hitcount: 4 2421ea272257SMauro Carvalho Chehab { lat: 12, common_pid: 2303 } hitcount: 1 2422ea272257SMauro Carvalho Chehab { lat: 12, common_pid: 2304 } hitcount: 122 2423ea272257SMauro Carvalho Chehab { lat: 13, common_pid: 2300 } hitcount: 12 2424ea272257SMauro Carvalho Chehab { lat: 13, common_pid: 2301 } hitcount: 1 2425ea272257SMauro Carvalho Chehab { lat: 13, common_pid: 2306 } hitcount: 32 2426ea272257SMauro Carvalho Chehab { lat: 13, common_pid: 2302 } hitcount: 5 2427ea272257SMauro Carvalho Chehab { lat: 13, common_pid: 2305 } hitcount: 1 2428ea272257SMauro Carvalho Chehab { lat: 13, common_pid: 2303 } hitcount: 1 2429ea272257SMauro Carvalho Chehab { lat: 13, common_pid: 2304 } hitcount: 61 2430ea272257SMauro Carvalho Chehab { lat: 14, common_pid: 2303 } hitcount: 4 2431ea272257SMauro Carvalho Chehab { lat: 14, common_pid: 2306 } hitcount: 5 2432ea272257SMauro Carvalho Chehab { lat: 14, common_pid: 2305 } hitcount: 4 2433ea272257SMauro Carvalho Chehab { lat: 14, common_pid: 2304 } hitcount: 62 2434ea272257SMauro Carvalho Chehab { lat: 14, common_pid: 2302 } hitcount: 19 2435ea272257SMauro Carvalho Chehab { lat: 14, common_pid: 2300 } hitcount: 33 2436ea272257SMauro Carvalho Chehab { lat: 14, common_pid: 2299 } hitcount: 1 2437ea272257SMauro Carvalho Chehab { lat: 14, common_pid: 2301 } hitcount: 4 2438ea272257SMauro Carvalho Chehab { lat: 15, common_pid: 2305 } hitcount: 1 2439ea272257SMauro Carvalho Chehab { lat: 15, common_pid: 2302 } hitcount: 25 2440ea272257SMauro Carvalho Chehab { lat: 15, common_pid: 2300 } hitcount: 11 2441ea272257SMauro Carvalho Chehab { lat: 15, common_pid: 2299 } hitcount: 5 2442ea272257SMauro Carvalho Chehab { lat: 15, common_pid: 2301 } hitcount: 1 2443ea272257SMauro Carvalho Chehab { lat: 15, common_pid: 2304 } hitcount: 8 2444ea272257SMauro Carvalho Chehab { lat: 15, common_pid: 2303 } hitcount: 1 2445ea272257SMauro Carvalho Chehab { lat: 15, common_pid: 2306 } hitcount: 6 2446ea272257SMauro Carvalho Chehab { lat: 16, common_pid: 2302 } hitcount: 31 2447ea272257SMauro Carvalho Chehab { lat: 16, common_pid: 2306 } hitcount: 3 2448ea272257SMauro Carvalho Chehab { lat: 16, common_pid: 2300 } hitcount: 5 2449ea272257SMauro Carvalho Chehab { lat: 17, common_pid: 2302 } hitcount: 6 2450ea272257SMauro Carvalho Chehab { lat: 17, common_pid: 2303 } hitcount: 1 2451ea272257SMauro Carvalho Chehab { lat: 18, common_pid: 2304 } hitcount: 1 2452ea272257SMauro Carvalho Chehab { lat: 18, common_pid: 2302 } hitcount: 8 2453ea272257SMauro Carvalho Chehab { lat: 18, common_pid: 2299 } hitcount: 1 2454ea272257SMauro Carvalho Chehab { lat: 18, common_pid: 2301 } hitcount: 1 2455ea272257SMauro Carvalho Chehab { lat: 19, common_pid: 2303 } hitcount: 4 2456ea272257SMauro Carvalho Chehab { lat: 19, common_pid: 2304 } hitcount: 5 2457ea272257SMauro Carvalho Chehab { lat: 19, common_pid: 2302 } hitcount: 4 2458ea272257SMauro Carvalho Chehab { lat: 19, common_pid: 2299 } hitcount: 3 2459ea272257SMauro Carvalho Chehab { lat: 19, common_pid: 2306 } hitcount: 1 2460ea272257SMauro Carvalho Chehab { lat: 19, common_pid: 2300 } hitcount: 4 2461ea272257SMauro Carvalho Chehab { lat: 19, common_pid: 2305 } hitcount: 5 2462ea272257SMauro Carvalho Chehab { lat: 20, common_pid: 2299 } hitcount: 2 2463ea272257SMauro Carvalho Chehab { lat: 20, common_pid: 2302 } hitcount: 3 2464ea272257SMauro Carvalho Chehab { lat: 20, common_pid: 2305 } hitcount: 1 2465ea272257SMauro Carvalho Chehab { lat: 20, common_pid: 2300 } hitcount: 2 2466ea272257SMauro Carvalho Chehab { lat: 20, common_pid: 2301 } hitcount: 2 2467ea272257SMauro Carvalho Chehab { lat: 20, common_pid: 2303 } hitcount: 3 2468ea272257SMauro Carvalho Chehab { lat: 21, common_pid: 2305 } hitcount: 1 2469ea272257SMauro Carvalho Chehab { lat: 21, common_pid: 2299 } hitcount: 5 2470ea272257SMauro Carvalho Chehab { lat: 21, common_pid: 2303 } hitcount: 4 2471ea272257SMauro Carvalho Chehab { lat: 21, common_pid: 2302 } hitcount: 7 2472ea272257SMauro Carvalho Chehab { lat: 21, common_pid: 2300 } hitcount: 1 2473ea272257SMauro Carvalho Chehab { lat: 21, common_pid: 2301 } hitcount: 5 2474ea272257SMauro Carvalho Chehab { lat: 21, common_pid: 2304 } hitcount: 2 2475ea272257SMauro Carvalho Chehab { lat: 22, common_pid: 2302 } hitcount: 5 2476ea272257SMauro Carvalho Chehab { lat: 22, common_pid: 2303 } hitcount: 1 2477ea272257SMauro Carvalho Chehab { lat: 22, common_pid: 2306 } hitcount: 3 2478ea272257SMauro Carvalho Chehab { lat: 22, common_pid: 2301 } hitcount: 2 2479ea272257SMauro Carvalho Chehab { lat: 22, common_pid: 2300 } hitcount: 1 2480ea272257SMauro Carvalho Chehab { lat: 22, common_pid: 2299 } hitcount: 1 2481ea272257SMauro Carvalho Chehab { lat: 22, common_pid: 2305 } hitcount: 1 2482ea272257SMauro Carvalho Chehab { lat: 22, common_pid: 2304 } hitcount: 1 2483ea272257SMauro Carvalho Chehab { lat: 23, common_pid: 2299 } hitcount: 1 2484ea272257SMauro Carvalho Chehab { lat: 23, common_pid: 2306 } hitcount: 2 2485ea272257SMauro Carvalho Chehab { lat: 23, common_pid: 2302 } hitcount: 6 2486ea272257SMauro Carvalho Chehab { lat: 24, common_pid: 2302 } hitcount: 3 2487ea272257SMauro Carvalho Chehab { lat: 24, common_pid: 2300 } hitcount: 1 2488ea272257SMauro Carvalho Chehab { lat: 24, common_pid: 2306 } hitcount: 2 2489ea272257SMauro Carvalho Chehab { lat: 24, common_pid: 2305 } hitcount: 1 2490ea272257SMauro Carvalho Chehab { lat: 24, common_pid: 2299 } hitcount: 1 2491ea272257SMauro Carvalho Chehab { lat: 25, common_pid: 2300 } hitcount: 1 2492ea272257SMauro Carvalho Chehab { lat: 25, common_pid: 2302 } hitcount: 4 2493ea272257SMauro Carvalho Chehab { lat: 26, common_pid: 2302 } hitcount: 2 2494ea272257SMauro Carvalho Chehab { lat: 27, common_pid: 2305 } hitcount: 1 2495ea272257SMauro Carvalho Chehab { lat: 27, common_pid: 2300 } hitcount: 1 2496ea272257SMauro Carvalho Chehab { lat: 27, common_pid: 2302 } hitcount: 3 2497ea272257SMauro Carvalho Chehab { lat: 28, common_pid: 2306 } hitcount: 1 2498ea272257SMauro Carvalho Chehab { lat: 28, common_pid: 2302 } hitcount: 4 2499ea272257SMauro Carvalho Chehab { lat: 29, common_pid: 2302 } hitcount: 1 2500ea272257SMauro Carvalho Chehab { lat: 29, common_pid: 2300 } hitcount: 2 2501ea272257SMauro Carvalho Chehab { lat: 29, common_pid: 2306 } hitcount: 1 2502ea272257SMauro Carvalho Chehab { lat: 29, common_pid: 2304 } hitcount: 1 2503ea272257SMauro Carvalho Chehab { lat: 30, common_pid: 2302 } hitcount: 4 2504ea272257SMauro Carvalho Chehab { lat: 31, common_pid: 2302 } hitcount: 6 2505ea272257SMauro Carvalho Chehab { lat: 32, common_pid: 2302 } hitcount: 1 2506ea272257SMauro Carvalho Chehab { lat: 33, common_pid: 2299 } hitcount: 1 2507ea272257SMauro Carvalho Chehab { lat: 33, common_pid: 2302 } hitcount: 3 2508ea272257SMauro Carvalho Chehab { lat: 34, common_pid: 2302 } hitcount: 2 2509ea272257SMauro Carvalho Chehab { lat: 35, common_pid: 2302 } hitcount: 1 2510ea272257SMauro Carvalho Chehab { lat: 35, common_pid: 2304 } hitcount: 1 2511ea272257SMauro Carvalho Chehab { lat: 36, common_pid: 2302 } hitcount: 4 2512ea272257SMauro Carvalho Chehab { lat: 37, common_pid: 2302 } hitcount: 6 2513ea272257SMauro Carvalho Chehab { lat: 38, common_pid: 2302 } hitcount: 2 2514ea272257SMauro Carvalho Chehab { lat: 39, common_pid: 2302 } hitcount: 2 2515ea272257SMauro Carvalho Chehab { lat: 39, common_pid: 2304 } hitcount: 1 2516ea272257SMauro Carvalho Chehab { lat: 40, common_pid: 2304 } hitcount: 2 2517ea272257SMauro Carvalho Chehab { lat: 40, common_pid: 2302 } hitcount: 5 2518ea272257SMauro Carvalho Chehab { lat: 41, common_pid: 2304 } hitcount: 1 2519ea272257SMauro Carvalho Chehab { lat: 41, common_pid: 2302 } hitcount: 8 2520ea272257SMauro Carvalho Chehab { lat: 42, common_pid: 2302 } hitcount: 6 2521ea272257SMauro Carvalho Chehab { lat: 42, common_pid: 2304 } hitcount: 1 2522ea272257SMauro Carvalho Chehab { lat: 43, common_pid: 2302 } hitcount: 3 2523ea272257SMauro Carvalho Chehab { lat: 43, common_pid: 2304 } hitcount: 4 2524ea272257SMauro Carvalho Chehab { lat: 44, common_pid: 2302 } hitcount: 6 2525ea272257SMauro Carvalho Chehab { lat: 45, common_pid: 2302 } hitcount: 5 2526ea272257SMauro Carvalho Chehab { lat: 46, common_pid: 2302 } hitcount: 5 2527ea272257SMauro Carvalho Chehab { lat: 47, common_pid: 2302 } hitcount: 7 2528ea272257SMauro Carvalho Chehab { lat: 48, common_pid: 2301 } hitcount: 1 2529ea272257SMauro Carvalho Chehab { lat: 48, common_pid: 2302 } hitcount: 9 2530ea272257SMauro Carvalho Chehab { lat: 49, common_pid: 2302 } hitcount: 3 2531ea272257SMauro Carvalho Chehab { lat: 50, common_pid: 2302 } hitcount: 1 2532ea272257SMauro Carvalho Chehab { lat: 50, common_pid: 2301 } hitcount: 1 2533ea272257SMauro Carvalho Chehab { lat: 51, common_pid: 2302 } hitcount: 2 2534ea272257SMauro Carvalho Chehab { lat: 51, common_pid: 2301 } hitcount: 1 2535ea272257SMauro Carvalho Chehab { lat: 61, common_pid: 2302 } hitcount: 1 2536ea272257SMauro Carvalho Chehab { lat: 110, common_pid: 2302 } hitcount: 1 2537ea272257SMauro Carvalho Chehab 2538ea272257SMauro Carvalho Chehab Totals: 2539ea272257SMauro Carvalho Chehab Hits: 89565 2540ea272257SMauro Carvalho Chehab Entries: 158 2541ea272257SMauro Carvalho Chehab Dropped: 0 2542ea272257SMauro Carvalho Chehab 2543ea272257SMauro Carvalho ChehabThis doesn't tell us any information about how late cyclictest may have 2544ea272257SMauro Carvalho Chehabwoken up, but it does show us a nice histogram of how long it took from 2545ea272257SMauro Carvalho Chehabthe time that cyclictest was woken to the time it made it into user space. 2546