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--event::
 39	List of syscalls and other perf events (tracepoints, HW cache events,
 40	etc) to show. Globbing is supported, e.g.: "epoll_*", "*msg*", etc.
 41	See 'perf list' for a complete list of events.
 42	Prefixing with ! shows all syscalls but the ones specified.  You may
 43	need to escape it.
 44
 45-D msecs::
 46--delay msecs::
 47After starting the program, wait msecs before measuring. This is useful to
 48filter out the startup phase of the program, which is often very different.
 49
 50-o::
 51--output=::
 52	Output file name.
 53
 54-p::
 55--pid=::
 56	Record events on existing process ID (comma separated list).
 57
 58-t::
 59--tid=::
 60        Record events on existing thread ID (comma separated list).
 61
 62-u::
 63--uid=::
 64        Record events in threads owned by uid. Name or number.
 65
 66-G::
 67--cgroup::
 68	Record events in threads in a cgroup.
 69
 70	Look for cgroups to set at the /sys/fs/cgroup/perf_event directory, then
 71	remove the /sys/fs/cgroup/perf_event/ part and try:
 72
 73		perf trace -G A -e sched:*switch
 74
 75	Will set all raw_syscalls:sys_{enter,exit}, pgfault, vfs_getname, etc
 76	_and_ sched:sched_switch to the 'A' cgroup, while:
 77
 78		perf trace -e sched:*switch -G A
 79
 80	will only set the sched:sched_switch event to the 'A' cgroup, all the
 81	other events (raw_syscalls:sys_{enter,exit}, etc are left "without"
 82	a cgroup (on the root cgroup, sys wide, etc).
 83
 84	Multiple cgroups:
 85
 86		perf trace -G A -e sched:*switch -G B
 87
 88	the syscall ones go to the 'A' cgroup, the sched:sched_switch goes
 89	to the 'B' cgroup.
 90
 91--filter-pids=::
 92	Filter out events for these pids and for 'trace' itself (comma separated list).
 93
 94-v::
 95--verbose=::
 96        Verbosity level.
 97
 98--no-inherit::
 99	Child tasks do not inherit counters.
100
101-m::
102--mmap-pages=::
103	Number of mmap data pages (must be a power of two) or size
104	specification with appended unit character - B/K/M/G. The
105	size is rounded up to have nearest pages power of two value.
106
107-C::
108--cpu::
109Collect samples only on the list of CPUs provided. Multiple CPUs can be provided as a
110comma-separated list with no space: 0,1. Ranges of CPUs are specified with -: 0-2.
111In per-thread mode with inheritance mode on (default), Events are captured only when
112the thread executes on the designated CPUs. Default is to monitor all CPUs.
113
114--duration::
115	Show only events that had a duration greater than N.M ms.
116
117--sched::
118	Accrue thread runtime and provide a summary at the end of the session.
119
120--failure::
121	Show only syscalls that failed, i.e. that returned < 0.
122
123-i::
124--input::
125	Process events from a given perf data file.
126
127-T::
128--time::
129	Print full timestamp rather time relative to first sample.
130
131--comm::
132        Show process COMM right beside its ID, on by default, disable with --no-comm.
133
134-s::
135--summary::
136	Show only a summary of syscalls by thread with min, max, and average times
137    (in msec) and relative stddev.
138
139-S::
140--with-summary::
141	Show all syscalls followed by a summary by thread with min, max, and
142    average times (in msec) and relative stddev.
143
144--tool_stats::
145	Show tool stats such as number of times fd->pathname was discovered thru
146	hooking the open syscall return + vfs_getname or via reading /proc/pid/fd, etc.
147
148-f::
149--force::
150	Don't complain, do it.
151
152-F=[all|min|maj]::
153--pf=[all|min|maj]::
154	Trace pagefaults. Optionally, you can specify whether you want minor,
155	major or all pagefaults. Default value is maj.
156
157--syscalls::
158	Trace system calls. This options is enabled by default, disable with
159	--no-syscalls.
160
161--call-graph [mode,type,min[,limit],order[,key][,branch]]::
162        Setup and enable call-graph (stack chain/backtrace) recording.
163        See `--call-graph` section in perf-record and perf-report
164        man pages for details. The ones that are most useful in 'perf trace'
165        are 'dwarf' and 'lbr', where available, try: 'perf trace --call-graph dwarf'.
166
167        Using this will, for the root user, bump the value of --mmap-pages to 4
168        times the maximum for non-root users, based on the kernel.perf_event_mlock_kb
169        sysctl. This is done only if the user doesn't specify a --mmap-pages value.
170
171--kernel-syscall-graph::
172	 Show the kernel callchains on the syscall exit path.
173
174--max-stack::
175        Set the stack depth limit when parsing the callchain, anything
176        beyond the specified depth will be ignored. Note that at this point
177        this is just about the presentation part, i.e. the kernel is still
178        not limiting, the overhead of callchains needs to be set via the
179        knobs in --call-graph dwarf.
180
181        Implies '--call-graph dwarf' when --call-graph not present on the
182        command line, on systems where DWARF unwinding was built in.
183
184        Default: /proc/sys/kernel/perf_event_max_stack when present for
185                 live sessions (without --input/-i), 127 otherwise.
186
187--min-stack::
188        Set the stack depth limit when parsing the callchain, anything
189        below the specified depth will be ignored. Disabled by default.
190
191        Implies '--call-graph dwarf' when --call-graph not present on the
192        command line, on systems where DWARF unwinding was built in.
193
194--print-sample::
195	Print the PERF_RECORD_SAMPLE PERF_SAMPLE_ info for the
196	raw_syscalls:sys_{enter,exit} tracepoints, for debugging.
197
198--proc-map-timeout::
199	When processing pre-existing threads /proc/XXX/mmap, it may take a long time,
200	because the file may be huge. A time out is needed in such cases.
201	This option sets the time out limit. The default value is 500 ms.
202
203PAGEFAULTS
204----------
205
206When tracing pagefaults, the format of the trace is as follows:
207
208<min|maj>fault [<ip.symbol>+<ip.offset>] => <addr.dso@addr.offset> (<map type><addr level>).
209
210- min/maj indicates whether fault event is minor or major;
211- ip.symbol shows symbol for instruction pointer (the code that generated the
212  fault); if no debug symbols available, perf trace will print raw IP;
213- addr.dso shows DSO for the faulted address;
214- map type is either 'd' for non-executable maps or 'x' for executable maps;
215- addr level is either 'k' for kernel dso or '.' for user dso.
216
217For symbols resolution you may need to install debugging symbols.
218
219Please be aware that duration is currently always 0 and doesn't reflect actual
220time it took for fault to be handled!
221
222When --verbose specified, perf trace tries to print all available information
223for both IP and fault address in the form of dso@symbol+offset.
224
225EXAMPLES
226--------
227
228Trace only major pagefaults:
229
230 $ perf trace --no-syscalls -F
231
232Trace syscalls, major and minor pagefaults:
233
234 $ perf trace -F all
235
236  1416.547 ( 0.000 ms): python/20235 majfault [CRYPTO_push_info_+0x0] => /lib/x86_64-linux-gnu/libcrypto.so.1.0.0@0x61be0 (x.)
237
238  As you can see, there was major pagefault in python process, from
239  CRYPTO_push_info_ routine which faulted somewhere in libcrypto.so.
240
241SEE ALSO
242--------
243linkperf:perf-record[1], linkperf:perf-script[1]