1perf-record(1)
2==============
3
4NAME
5----
6perf-record - Run a command and record its profile into perf.data
7
8SYNOPSIS
9--------
10[verse]
11'perf record' [-e <EVENT> | --event=EVENT] [-a] <command>
12'perf record' [-e <EVENT> | --event=EVENT] [-a] -- <command> [<options>]
13
14DESCRIPTION
15-----------
16This command runs a command and gathers a performance counter profile
17from it, into perf.data - without displaying anything.
18
19This file can then be inspected later on, using 'perf report'.
20
21
22OPTIONS
23-------
24<command>...::
25	Any command you can specify in a shell.
26
27-e::
28--event=::
29	Select the PMU event. Selection can be:
30
31        - a symbolic event name	(use 'perf list' to list all events)
32
33        - a raw PMU event (eventsel+umask) in the form of rNNN where NNN is a
34	  hexadecimal event descriptor.
35
36	- a symbolically formed PMU event like 'pmu/param1=0x3,param2/' where
37	  'param1', 'param2', etc are defined as formats for the PMU in
38	  /sys/bus/event_source/devices/<pmu>/format/*.
39
40	- a symbolically formed event like 'pmu/config=M,config1=N,config3=K/'
41
42          where M, N, K are numbers (in decimal, hex, octal format). Acceptable
43          values for each of 'config', 'config1' and 'config2' are defined by
44          corresponding entries in /sys/bus/event_source/devices/<pmu>/format/*
45          param1 and param2 are defined as formats for the PMU in:
46          /sys/bus/event_source/devices/<pmu>/format/*
47
48	  There are also some parameters which are not defined in .../<pmu>/format/*.
49	  These params can be used to overload default config values per event.
50	  Here are some common parameters:
51	  - 'period': Set event sampling period
52	  - 'freq': Set event sampling frequency
53	  - 'time': Disable/enable time stamping. Acceptable values are 1 for
54		    enabling time stamping. 0 for disabling time stamping.
55		    The default is 1.
56	  - 'call-graph': Disable/enable callgraph. Acceptable str are "fp" for
57			 FP mode, "dwarf" for DWARF mode, "lbr" for LBR mode and
58			 "no" for disable callgraph.
59	  - 'stack-size': user stack size for dwarf mode
60
61          See the linkperf:perf-list[1] man page for more parameters.
62
63	  Note: If user explicitly sets options which conflict with the params,
64	  the value set by the parameters will be overridden.
65
66	  Also not defined in .../<pmu>/format/* are PMU driver specific
67	  configuration parameters.  Any configuration parameter preceded by
68	  the letter '@' is not interpreted in user space and sent down directly
69	  to the PMU driver.  For example:
70
71	  perf record -e some_event/@cfg1,@cfg2=config/ ...
72
73	  will see 'cfg1' and 'cfg2=config' pushed to the PMU driver associated
74	  with the event for further processing.  There is no restriction on
75	  what the configuration parameters are, as long as their semantic is
76	  understood and supported by the PMU driver.
77
78        - a hardware breakpoint event in the form of '\mem:addr[/len][:access]'
79          where addr is the address in memory you want to break in.
80          Access is the memory access type (read, write, execute) it can
81          be passed as follows: '\mem:addr[:[r][w][x]]'. len is the range,
82          number of bytes from specified addr, which the breakpoint will cover.
83          If you want to profile read-write accesses in 0x1000, just set
84          'mem:0x1000:rw'.
85          If you want to profile write accesses in [0x1000~1008), just set
86          'mem:0x1000/8:w'.
87
88	- a group of events surrounded by a pair of brace ("{event1,event2,...}").
89	  Each event is separated by commas and the group should be quoted to
90	  prevent the shell interpretation.  You also need to use --group on
91	  "perf report" to view group events together.
92
93--filter=<filter>::
94        Event filter. This option should follow a event selector (-e) which
95	selects either tracepoint event(s) or a hardware trace PMU
96	(e.g. Intel PT or CoreSight).
97
98	- tracepoint filters
99
100	In the case of tracepoints, multiple '--filter' options are combined
101	using '&&'.
102
103	- address filters
104
105	A hardware trace PMU advertises its ability to accept a number of
106	address filters	by specifying a non-zero value in
107	/sys/bus/event_source/devices/<pmu>/nr_addr_filters.
108
109	Address filters have the format:
110
111	filter|start|stop|tracestop <start> [/ <size>] [@<file name>]
112
113	Where:
114	- 'filter': defines a region that will be traced.
115	- 'start': defines an address at which tracing will begin.
116	- 'stop': defines an address at which tracing will stop.
117	- 'tracestop': defines a region in which tracing will stop.
118
119	<file name> is the name of the object file, <start> is the offset to the
120	code to trace in that file, and <size> is the size of the region to
121	trace. 'start' and 'stop' filters need not specify a <size>.
122
123	If no object file is specified then the kernel is assumed, in which case
124	the start address must be a current kernel memory address.
125
126	<start> can also be specified by providing the name of a symbol. If the
127	symbol name is not unique, it can be disambiguated by inserting #n where
128	'n' selects the n'th symbol in address order. Alternately #0, #g or #G
129	select only a global symbol. <size> can also be specified by providing
130	the name of a symbol, in which case the size is calculated to the end
131	of that symbol. For 'filter' and 'tracestop' filters, if <size> is
132	omitted and <start> is a symbol, then the size is calculated to the end
133	of that symbol.
134
135	If <size> is omitted and <start> is '*', then the start and size will
136	be calculated from the first and last symbols, i.e. to trace the whole
137	file.
138
139	If symbol names (or '*') are provided, they must be surrounded by white
140	space.
141
142	The filter passed to the kernel is not necessarily the same as entered.
143	To see the filter that is passed, use the -v option.
144
145	The kernel may not be able to configure a trace region if it is not
146	within a single mapping.  MMAP events (or /proc/<pid>/maps) can be
147	examined to determine if that is a possibility.
148
149	Multiple filters can be separated with space or comma.
150
151--exclude-perf::
152	Don't record events issued by perf itself. This option should follow
153	a event selector (-e) which selects tracepoint event(s). It adds a
154	filter expression 'common_pid != $PERFPID' to filters. If other
155	'--filter' exists, the new filter expression will be combined with
156	them by '&&'.
157
158-a::
159--all-cpus::
160        System-wide collection from all CPUs (default if no target is specified).
161
162-p::
163--pid=::
164	Record events on existing process ID (comma separated list).
165
166-t::
167--tid=::
168        Record events on existing thread ID (comma separated list).
169        This option also disables inheritance by default.  Enable it by adding
170        --inherit.
171
172-u::
173--uid=::
174        Record events in threads owned by uid. Name or number.
175
176-r::
177--realtime=::
178	Collect data with this RT SCHED_FIFO priority.
179
180--no-buffering::
181	Collect data without buffering.
182
183-c::
184--count=::
185	Event period to sample.
186
187-o::
188--output=::
189	Output file name.
190
191-i::
192--no-inherit::
193	Child tasks do not inherit counters.
194
195-F::
196--freq=::
197	Profile at this frequency. Use 'max' to use the currently maximum
198	allowed frequency, i.e. the value in the kernel.perf_event_max_sample_rate
199	sysctl. Will throttle down to the currently maximum allowed frequency.
200	See --strict-freq.
201
202--strict-freq::
203	Fail if the specified frequency can't be used.
204
205-m::
206--mmap-pages=::
207	Number of mmap data pages (must be a power of two) or size
208	specification with appended unit character - B/K/M/G. The
209	size is rounded up to have nearest pages power of two value.
210	Also, by adding a comma, the number of mmap pages for AUX
211	area tracing can be specified.
212
213--group::
214	Put all events in a single event group.  This precedes the --event
215	option and remains only for backward compatibility.  See --event.
216
217-g::
218	Enables call-graph (stack chain/backtrace) recording.
219
220--call-graph::
221	Setup and enable call-graph (stack chain/backtrace) recording,
222	implies -g.  Default is "fp".
223
224	Allows specifying "fp" (frame pointer) or "dwarf"
225	(DWARF's CFI - Call Frame Information) or "lbr"
226	(Hardware Last Branch Record facility) as the method to collect
227	the information used to show the call graphs.
228
229	In some systems, where binaries are build with gcc
230	--fomit-frame-pointer, using the "fp" method will produce bogus
231	call graphs, using "dwarf", if available (perf tools linked to
232	the libunwind or libdw library) should be used instead.
233	Using the "lbr" method doesn't require any compiler options. It
234	will produce call graphs from the hardware LBR registers. The
235	main limitation is that it is only available on new Intel
236	platforms, such as Haswell. It can only get user call chain. It
237	doesn't work with branch stack sampling at the same time.
238
239	When "dwarf" recording is used, perf also records (user) stack dump
240	when sampled.  Default size of the stack dump is 8192 (bytes).
241	User can change the size by passing the size after comma like
242	"--call-graph dwarf,4096".
243
244-q::
245--quiet::
246	Don't print any message, useful for scripting.
247
248-v::
249--verbose::
250	Be more verbose (show counter open errors, etc).
251
252-s::
253--stat::
254	Record per-thread event counts.  Use it with 'perf report -T' to see
255	the values.
256
257-d::
258--data::
259	Record the sample virtual addresses.
260
261--phys-data::
262	Record the sample physical addresses.
263
264-T::
265--timestamp::
266	Record the sample timestamps. Use it with 'perf report -D' to see the
267	timestamps, for instance.
268
269-P::
270--period::
271	Record the sample period.
272
273--sample-cpu::
274	Record the sample cpu.
275
276-n::
277--no-samples::
278	Don't sample.
279
280-R::
281--raw-samples::
282Collect raw sample records from all opened counters (default for tracepoint counters).
283
284-C::
285--cpu::
286Collect samples only on the list of CPUs provided. Multiple CPUs can be provided as a
287comma-separated list with no space: 0,1. Ranges of CPUs are specified with -: 0-2.
288In per-thread mode with inheritance mode on (default), samples are captured only when
289the thread executes on the designated CPUs. Default is to monitor all CPUs.
290
291-B::
292--no-buildid::
293Do not save the build ids of binaries in the perf.data files. This skips
294post processing after recording, which sometimes makes the final step in
295the recording process to take a long time, as it needs to process all
296events looking for mmap records. The downside is that it can misresolve
297symbols if the workload binaries used when recording get locally rebuilt
298or upgraded, because the only key available in this case is the
299pathname. You can also set the "record.build-id" config variable to
300'skip to have this behaviour permanently.
301
302-N::
303--no-buildid-cache::
304Do not update the buildid cache. This saves some overhead in situations
305where the information in the perf.data file (which includes buildids)
306is sufficient.  You can also set the "record.build-id" config variable to
307'no-cache' to have the same effect.
308
309-G name,...::
310--cgroup name,...::
311monitor only in the container (cgroup) called "name". This option is available only
312in per-cpu mode. The cgroup filesystem must be mounted. All threads belonging to
313container "name" are monitored when they run on the monitored CPUs. Multiple cgroups
314can be provided. Each cgroup is applied to the corresponding event, i.e., first cgroup
315to first event, second cgroup to second event and so on. It is possible to provide
316an empty cgroup (monitor all the time) using, e.g., -G foo,,bar. Cgroups must have
317corresponding events, i.e., they always refer to events defined earlier on the command
318line. If the user wants to track multiple events for a specific cgroup, the user can
319use '-e e1 -e e2 -G foo,foo' or just use '-e e1 -e e2 -G foo'.
320
321If wanting to monitor, say, 'cycles' for a cgroup and also for system wide, this
322command line can be used: 'perf stat -e cycles -G cgroup_name -a -e cycles'.
323
324-b::
325--branch-any::
326Enable taken branch stack sampling. Any type of taken branch may be sampled.
327This is a shortcut for --branch-filter any. See --branch-filter for more infos.
328
329-j::
330--branch-filter::
331Enable taken branch stack sampling. Each sample captures a series of consecutive
332taken branches. The number of branches captured with each sample depends on the
333underlying hardware, the type of branches of interest, and the executed code.
334It is possible to select the types of branches captured by enabling filters. The
335following filters are defined:
336
337        - any:  any type of branches
338        - any_call: any function call or system call
339        - any_ret: any function return or system call return
340        - ind_call: any indirect branch
341        - call: direct calls, including far (to/from kernel) calls
342        - u:  only when the branch target is at the user level
343        - k: only when the branch target is in the kernel
344        - hv: only when the target is at the hypervisor level
345	- in_tx: only when the target is in a hardware transaction
346	- no_tx: only when the target is not in a hardware transaction
347	- abort_tx: only when the target is a hardware transaction abort
348	- cond: conditional branches
349	- save_type: save branch type during sampling in case binary is not available later
350
351+
352The option requires at least one branch type among any, any_call, any_ret, ind_call, cond.
353The privilege levels may be omitted, in which case, the privilege levels of the associated
354event are applied to the branch filter. Both kernel (k) and hypervisor (hv) privilege
355levels are subject to permissions.  When sampling on multiple events, branch stack sampling
356is enabled for all the sampling events. The sampled branch type is the same for all events.
357The various filters must be specified as a comma separated list: --branch-filter any_ret,u,k
358Note that this feature may not be available on all processors.
359
360--weight::
361Enable weightened sampling. An additional weight is recorded per sample and can be
362displayed with the weight and local_weight sort keys.  This currently works for TSX
363abort events and some memory events in precise mode on modern Intel CPUs.
364
365--namespaces::
366Record events of type PERF_RECORD_NAMESPACES.
367
368--transaction::
369Record transaction flags for transaction related events.
370
371--per-thread::
372Use per-thread mmaps.  By default per-cpu mmaps are created.  This option
373overrides that and uses per-thread mmaps.  A side-effect of that is that
374inheritance is automatically disabled.  --per-thread is ignored with a warning
375if combined with -a or -C options.
376
377-D::
378--delay=::
379After starting the program, wait msecs before measuring. This is useful to
380filter out the startup phase of the program, which is often very different.
381
382-I::
383--intr-regs::
384Capture machine state (registers) at interrupt, i.e., on counter overflows for
385each sample. List of captured registers depends on the architecture. This option
386is off by default. It is possible to select the registers to sample using their
387symbolic names, e.g. on x86, ax, si. To list the available registers use
388--intr-regs=\?. To name registers, pass a comma separated list such as
389--intr-regs=ax,bx. The list of register is architecture dependent.
390
391--user-regs::
392Capture user registers at sample time. Same arguments as -I.
393
394--running-time::
395Record running and enabled time for read events (:S)
396
397-k::
398--clockid::
399Sets the clock id to use for the various time fields in the perf_event_type
400records. See clock_gettime(). In particular CLOCK_MONOTONIC and
401CLOCK_MONOTONIC_RAW are supported, some events might also allow
402CLOCK_BOOTTIME, CLOCK_REALTIME and CLOCK_TAI.
403
404-S::
405--snapshot::
406Select AUX area tracing Snapshot Mode. This option is valid only with an
407AUX area tracing event. Optionally the number of bytes to capture per
408snapshot can be specified. In Snapshot Mode, trace data is captured only when
409signal SIGUSR2 is received.
410
411--proc-map-timeout::
412When processing pre-existing threads /proc/XXX/mmap, it may take a long time,
413because the file may be huge. A time out is needed in such cases.
414This option sets the time out limit. The default value is 500 ms.
415
416--switch-events::
417Record context switch events i.e. events of type PERF_RECORD_SWITCH or
418PERF_RECORD_SWITCH_CPU_WIDE.
419
420--clang-path=PATH::
421Path to clang binary to use for compiling BPF scriptlets.
422(enabled when BPF support is on)
423
424--clang-opt=OPTIONS::
425Options passed to clang when compiling BPF scriptlets.
426(enabled when BPF support is on)
427
428--vmlinux=PATH::
429Specify vmlinux path which has debuginfo.
430(enabled when BPF prologue is on)
431
432--buildid-all::
433Record build-id of all DSOs regardless whether it's actually hit or not.
434
435--all-kernel::
436Configure all used events to run in kernel space.
437
438--all-user::
439Configure all used events to run in user space.
440
441--timestamp-filename
442Append timestamp to output file name.
443
444--timestamp-boundary::
445Record timestamp boundary (time of first/last samples).
446
447--switch-output[=mode]::
448Generate multiple perf.data files, timestamp prefixed, switching to a new one
449based on 'mode' value:
450  "signal" - when receiving a SIGUSR2 (default value) or
451  <size>   - when reaching the size threshold, size is expected to
452             be a number with appended unit character - B/K/M/G
453  <time>   - when reaching the time threshold, size is expected to
454             be a number with appended unit character - s/m/h/d
455
456             Note: the precision of  the size  threshold  hugely depends
457             on your configuration  - the number and size of  your  ring
458             buffers (-m). It is generally more precise for higher sizes
459             (like >5M), for lower values expect different sizes.
460
461A possible use case is to, given an external event, slice the perf.data file
462that gets then processed, possibly via a perf script, to decide if that
463particular perf.data snapshot should be kept or not.
464
465Implies --timestamp-filename, --no-buildid and --no-buildid-cache.
466The reason for the latter two is to reduce the data file switching
467overhead. You can still switch them on with:
468
469  --switch-output --no-no-buildid  --no-no-buildid-cache
470
471--dry-run::
472Parse options then exit. --dry-run can be used to detect errors in cmdline
473options.
474
475'perf record --dry-run -e' can act as a BPF script compiler if llvm.dump-obj
476in config file is set to true.
477
478--tail-synthesize::
479Instead of collecting non-sample events (for example, fork, comm, mmap) at
480the beginning of record, collect them during finalizing an output file.
481The collected non-sample events reflects the status of the system when
482record is finished.
483
484--overwrite::
485Makes all events use an overwritable ring buffer. An overwritable ring
486buffer works like a flight recorder: when it gets full, the kernel will
487overwrite the oldest records, that thus will never make it to the
488perf.data file.
489
490When '--overwrite' and '--switch-output' are used perf records and drops
491events until it receives a signal, meaning that something unusual was
492detected that warrants taking a snapshot of the most current events,
493those fitting in the ring buffer at that moment.
494
495'overwrite' attribute can also be set or canceled for an event using
496config terms. For example: 'cycles/overwrite/' and 'instructions/no-overwrite/'.
497
498Implies --tail-synthesize.
499
500SEE ALSO
501--------
502linkperf:perf-stat[1], linkperf:perf-list[1]
503