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