1perf-trace(1)
2=============
3
4NAME
5----
6perf-trace - strace inspired tool
7
8SYNOPSIS
9--------
10[verse]
11'perf trace'
12'perf trace record'
13
14DESCRIPTION
15-----------
16This command will show the events associated with the target, initially
17syscalls, but other system events like pagefaults, task lifetime events,
18scheduling events, etc.
19
20This is a live mode tool in addition to working with perf.data files like
21the other perf tools. Files can be generated using the 'perf record' command
22but the session needs to include the raw_syscalls events (-e 'raw_syscalls:*').
23Alternatively, 'perf trace record' can be used as a shortcut to
24automatically include the raw_syscalls events when writing events to a file.
25
26The following options apply to perf trace; options to perf trace record are
27found in the perf record man page.
28
29OPTIONS
30-------
31
32-a::
33--all-cpus::
34        System-wide collection from all CPUs.
35
36-e::
37--expr::
38	List of syscalls to show, currently only syscall names.
39	Prefixing with ! shows all syscalls but the ones specified.  You may
40	need to escape it.
41
42-o::
43--output=::
44	Output file name.
45
46-p::
47--pid=::
48	Record events on existing process ID (comma separated list).
49
50-t::
51--tid=::
52        Record events on existing thread ID (comma separated list).
53
54-u::
55--uid=::
56        Record events in threads owned by uid. Name or number.
57
58--filter-pids=::
59	Filter out events for these pids and for 'trace' itself (comma separated list).
60
61-v::
62--verbose=::
63        Verbosity level.
64
65--no-inherit::
66	Child tasks do not inherit counters.
67
68-m::
69--mmap-pages=::
70	Number of mmap data pages (must be a power of two) or size
71	specification with appended unit character - B/K/M/G. The
72	size is rounded up to have nearest pages power of two value.
73
74-C::
75--cpu::
76Collect samples only on the list of CPUs provided. Multiple CPUs can be provided as a
77comma-separated list with no space: 0,1. Ranges of CPUs are specified with -: 0-2.
78In per-thread mode with inheritance mode on (default), Events are captured only when
79the thread executes on the designated CPUs. Default is to monitor all CPUs.
80
81--duration:
82	Show only events that had a duration greater than N.M ms.
83
84--sched:
85	Accrue thread runtime and provide a summary at the end of the session.
86
87-i
88--input
89	Process events from a given perf data file.
90
91-T
92--time
93	Print full timestamp rather time relative to first sample.
94
95--comm::
96        Show process COMM right beside its ID, on by default, disable with --no-comm.
97
98-s::
99--summary::
100	Show only a summary of syscalls by thread with min, max, and average times
101    (in msec) and relative stddev.
102
103-S::
104--with-summary::
105	Show all syscalls followed by a summary by thread with min, max, and
106    average times (in msec) and relative stddev.
107
108--tool_stats::
109	Show tool stats such as number of times fd->pathname was discovered thru
110	hooking the open syscall return + vfs_getname or via reading /proc/pid/fd, etc.
111
112-F=[all|min|maj]::
113--pf=[all|min|maj]::
114	Trace pagefaults. Optionally, you can specify whether you want minor,
115	major or all pagefaults. Default value is maj.
116
117--syscalls::
118	Trace system calls. This options is enabled by default.
119
120--call-graph [mode,type,min[,limit],order[,key][,branch]]::
121        Setup and enable call-graph (stack chain/backtrace) recording.
122        See `--call-graph` section in perf-record and perf-report
123        man pages for details. The ones that are most useful in 'perf trace'
124        are 'dwarf' and 'lbr', where available, try: 'perf trace --call-graph dwarf'.
125
126        Using this will, for the root user, bump the value of --mmap-pages to 4
127        times the maximum for non-root users, based on the kernel.perf_event_mlock_kb
128        sysctl. This is done only if the user doesn't specify a --mmap-pages value.
129
130--kernel-syscall-graph::
131	 Show the kernel callchains on the syscall exit path.
132
133--event::
134	Trace other events, see 'perf list' for a complete list.
135
136--max-stack::
137        Set the stack depth limit when parsing the callchain, anything
138        beyond the specified depth will be ignored. Note that at this point
139        this is just about the presentation part, i.e. the kernel is still
140        not limiting, the overhead of callchains needs to be set via the
141        knobs in --call-graph dwarf.
142
143        Implies '--call-graph dwarf' when --call-graph not present on the
144        command line, on systems where DWARF unwinding was built in.
145
146        Default: /proc/sys/kernel/perf_event_max_stack when present for
147                 live sessions (without --input/-i), 127 otherwise.
148
149--min-stack::
150        Set the stack depth limit when parsing the callchain, anything
151        below the specified depth will be ignored. Disabled by default.
152
153        Implies '--call-graph dwarf' when --call-graph not present on the
154        command line, on systems where DWARF unwinding was built in.
155
156--proc-map-timeout::
157	When processing pre-existing threads /proc/XXX/mmap, it may take a long time,
158	because the file may be huge. A time out is needed in such cases.
159	This option sets the time out limit. The default value is 500 ms.
160
161PAGEFAULTS
162----------
163
164When tracing pagefaults, the format of the trace is as follows:
165
166<min|maj>fault [<ip.symbol>+<ip.offset>] => <addr.dso@addr.offset> (<map type><addr level>).
167
168- min/maj indicates whether fault event is minor or major;
169- ip.symbol shows symbol for instruction pointer (the code that generated the
170  fault); if no debug symbols available, perf trace will print raw IP;
171- addr.dso shows DSO for the faulted address;
172- map type is either 'd' for non-executable maps or 'x' for executable maps;
173- addr level is either 'k' for kernel dso or '.' for user dso.
174
175For symbols resolution you may need to install debugging symbols.
176
177Please be aware that duration is currently always 0 and doesn't reflect actual
178time it took for fault to be handled!
179
180When --verbose specified, perf trace tries to print all available information
181for both IP and fault address in the form of dso@symbol+offset.
182
183EXAMPLES
184--------
185
186Trace only major pagefaults:
187
188 $ perf trace --no-syscalls -F
189
190Trace syscalls, major and minor pagefaults:
191
192 $ perf trace -F all
193
194  1416.547 ( 0.000 ms): python/20235 majfault [CRYPTO_push_info_+0x0] => /lib/x86_64-linux-gnu/libcrypto.so.1.0.0@0x61be0 (x.)
195
196  As you can see, there was major pagefault in python process, from
197  CRYPTO_push_info_ routine which faulted somewhere in libcrypto.so.
198
199SEE ALSO
200--------
201linkperf:perf-record[1], linkperf:perf-script[1]
202