1 perf-trace(1) 1 perf-trace(1)
2 ============= 2 =============
3 3
4 NAME 4 NAME
5 ---- 5 ----
6 perf-trace - strace inspired tool 6 perf-trace - strace inspired tool
7 7
8 SYNOPSIS 8 SYNOPSIS
9 -------- 9 --------
10 [verse] 10 [verse]
11 'perf trace' 11 'perf trace'
12 'perf trace record' 12 'perf trace record'
13 13
14 DESCRIPTION 14 DESCRIPTION
15 ----------- 15 -----------
16 This command will show the events associated w 16 This command will show the events associated with the target, initially
17 syscalls, but other system events like pagefau 17 syscalls, but other system events like pagefaults, task lifetime events,
18 scheduling events, etc. 18 scheduling events, etc.
19 19
20 This is a live mode tool in addition to workin 20 This is a live mode tool in addition to working with perf.data files like
21 the other perf tools. Files can be generated u 21 the other perf tools. Files can be generated using the 'perf record' command
22 but the session needs to include the raw_sysca 22 but the session needs to include the raw_syscalls events (-e 'raw_syscalls:*').
23 Alternatively, 'perf trace record' can be used 23 Alternatively, 'perf trace record' can be used as a shortcut to
24 automatically include the raw_syscalls events 24 automatically include the raw_syscalls events when writing events to a file.
25 25
26 The following options apply to perf trace; opt 26 The following options apply to perf trace; options to perf trace record are
27 found in the perf record man page. 27 found in the perf record man page.
28 28
29 OPTIONS 29 OPTIONS
30 ------- 30 -------
31 31
32 -a:: 32 -a::
33 --all-cpus:: 33 --all-cpus::
34 System-wide collection from all CPUs. 34 System-wide collection from all CPUs.
35 35
36 -e:: 36 -e::
37 --expr:: 37 --expr::
38 --event:: 38 --event::
39 List of syscalls and other perf events 39 List of syscalls and other perf events (tracepoints, HW cache events,
40 etc) to show. Globbing is supported, e 40 etc) to show. Globbing is supported, e.g.: "epoll_*", "*msg*", etc.
41 See 'perf list' for a complete list of 41 See 'perf list' for a complete list of events.
42 Prefixing with ! shows all syscalls bu 42 Prefixing with ! shows all syscalls but the ones specified. You may
43 need to escape it. 43 need to escape it.
44 44
45 --filter=<filter>:: <<
46 Event filter. This option should follo <<
47 selects tracepoint event(s). <<
48 <<
49 <<
50 -D msecs:: 45 -D msecs::
51 --delay msecs:: 46 --delay msecs::
52 After starting the program, wait msecs before 47 After starting the program, wait msecs before measuring. This is useful to
53 filter out the startup phase of the program, w 48 filter out the startup phase of the program, which is often very different.
54 49
55 -o:: 50 -o::
56 --output=:: 51 --output=::
57 Output file name. 52 Output file name.
58 53
59 -p:: 54 -p::
60 --pid=:: 55 --pid=::
61 Record events on existing process ID ( 56 Record events on existing process ID (comma separated list).
62 57
63 -t:: 58 -t::
64 --tid=:: 59 --tid=::
65 Record events on existing thread ID (c 60 Record events on existing thread ID (comma separated list).
66 61
67 -u:: 62 -u::
68 --uid=:: 63 --uid=::
69 Record events in threads owned by uid. 64 Record events in threads owned by uid. Name or number.
70 65
71 -G:: 66 -G::
72 --cgroup:: 67 --cgroup::
73 Record events in threads in a cgroup. 68 Record events in threads in a cgroup.
74 69
75 Look for cgroups to set at the /sys/fs 70 Look for cgroups to set at the /sys/fs/cgroup/perf_event directory, then
76 remove the /sys/fs/cgroup/perf_event/ 71 remove the /sys/fs/cgroup/perf_event/ part and try:
77 72
78 perf trace -G A -e sched:*swit 73 perf trace -G A -e sched:*switch
79 74
80 Will set all raw_syscalls:sys_{enter,e 75 Will set all raw_syscalls:sys_{enter,exit}, pgfault, vfs_getname, etc
81 _and_ sched:sched_switch to the 'A' cg 76 _and_ sched:sched_switch to the 'A' cgroup, while:
82 77
83 perf trace -e sched:*switch -G 78 perf trace -e sched:*switch -G A
84 79
85 will only set the sched:sched_switch e 80 will only set the sched:sched_switch event to the 'A' cgroup, all the
86 other events (raw_syscalls:sys_{enter, 81 other events (raw_syscalls:sys_{enter,exit}, etc are left "without"
87 a cgroup (on the root cgroup, sys wide 82 a cgroup (on the root cgroup, sys wide, etc).
88 83
89 Multiple cgroups: 84 Multiple cgroups:
90 85
91 perf trace -G A -e sched:*swit 86 perf trace -G A -e sched:*switch -G B
92 87
93 the syscall ones go to the 'A' cgroup, 88 the syscall ones go to the 'A' cgroup, the sched:sched_switch goes
94 to the 'B' cgroup. 89 to the 'B' cgroup.
95 90
96 --filter-pids=:: 91 --filter-pids=::
97 Filter out events for these pids and f 92 Filter out events for these pids and for 'trace' itself (comma separated list).
98 93
99 -v:: 94 -v::
100 --verbose:: !! 95 --verbose=::
101 Increase the verbosity level. !! 96 Verbosity level.
102 97
103 --no-inherit:: 98 --no-inherit::
104 Child tasks do not inherit counters. 99 Child tasks do not inherit counters.
105 100
106 -m:: 101 -m::
107 --mmap-pages=:: 102 --mmap-pages=::
108 Number of mmap data pages (must be a p 103 Number of mmap data pages (must be a power of two) or size
109 specification in bytes with appended u !! 104 specification with appended unit character - B/K/M/G. The
110 The size is rounded up to the nearest !! 105 size is rounded up to have nearest pages power of two value.
111 106
112 -C:: 107 -C::
113 --cpu:: 108 --cpu::
114 Collect samples only on the list of CPUs provi 109 Collect samples only on the list of CPUs provided. Multiple CPUs can be provided as a
115 comma-separated list with no space: 0,1. Range 110 comma-separated list with no space: 0,1. Ranges of CPUs are specified with -: 0-2.
116 In per-thread mode with inheritance mode on (d 111 In per-thread mode with inheritance mode on (default), Events are captured only when
117 the thread executes on the designated CPUs. De 112 the thread executes on the designated CPUs. Default is to monitor all CPUs.
118 113
119 --duration:: 114 --duration::
120 Show only events that had a duration g 115 Show only events that had a duration greater than N.M ms.
121 116
122 --sched:: 117 --sched::
123 Accrue thread runtime and provide a su 118 Accrue thread runtime and provide a summary at the end of the session.
124 119
125 --failure:: 120 --failure::
126 Show only syscalls that failed, i.e. t 121 Show only syscalls that failed, i.e. that returned < 0.
127 122
128 -i:: 123 -i::
129 --input:: 124 --input::
130 Process events from a given perf data 125 Process events from a given perf data file.
131 126
132 -T:: 127 -T::
133 --time:: 128 --time::
134 Print full timestamp rather time relat 129 Print full timestamp rather time relative to first sample.
135 130
136 --comm:: 131 --comm::
137 Show process COMM right beside its ID, 132 Show process COMM right beside its ID, on by default, disable with --no-comm.
138 133
139 -s:: 134 -s::
140 --summary:: 135 --summary::
141 Show only a summary of syscalls by thr 136 Show only a summary of syscalls by thread with min, max, and average times
142 (in msec) and relative stddev. 137 (in msec) and relative stddev.
143 138
144 -S:: 139 -S::
145 --with-summary:: 140 --with-summary::
146 Show all syscalls followed by a summar 141 Show all syscalls followed by a summary by thread with min, max, and
147 average times (in msec) and relative stdde 142 average times (in msec) and relative stddev.
148 143
149 --errno-summary:: <<
150 To be used with -s or -S, to show stat <<
151 syscalls, using only this option will <<
152 <<
153 --tool_stats:: 144 --tool_stats::
154 Show tool stats such as number of time 145 Show tool stats such as number of times fd->pathname was discovered thru
155 hooking the open syscall return + vfs_ 146 hooking the open syscall return + vfs_getname or via reading /proc/pid/fd, etc.
156 147
157 -f:: 148 -f::
158 --force:: 149 --force::
159 Don't complain, do it. 150 Don't complain, do it.
160 151
161 -F=[all|min|maj]:: 152 -F=[all|min|maj]::
162 --pf=[all|min|maj]:: 153 --pf=[all|min|maj]::
163 Trace pagefaults. Optionally, you can 154 Trace pagefaults. Optionally, you can specify whether you want minor,
164 major or all pagefaults. Default value 155 major or all pagefaults. Default value is maj.
165 156
166 --syscalls:: 157 --syscalls::
167 Trace system calls. This options is en 158 Trace system calls. This options is enabled by default, disable with
168 --no-syscalls. 159 --no-syscalls.
169 160
170 --call-graph [mode,type,min[,limit],order[,key 161 --call-graph [mode,type,min[,limit],order[,key][,branch]]::
171 Setup and enable call-graph (stack cha 162 Setup and enable call-graph (stack chain/backtrace) recording.
172 See `--call-graph` section in perf-rec 163 See `--call-graph` section in perf-record and perf-report
173 man pages for details. The ones that a 164 man pages for details. The ones that are most useful in 'perf trace'
174 are 'dwarf' and 'lbr', where available 165 are 'dwarf' and 'lbr', where available, try: 'perf trace --call-graph dwarf'.
175 166
176 Using this will, for the root user, bu 167 Using this will, for the root user, bump the value of --mmap-pages to 4
177 times the maximum for non-root users, 168 times the maximum for non-root users, based on the kernel.perf_event_mlock_kb
178 sysctl. This is done only if the user 169 sysctl. This is done only if the user doesn't specify a --mmap-pages value.
179 170
180 --kernel-syscall-graph:: 171 --kernel-syscall-graph::
181 Show the kernel callchains on the sys 172 Show the kernel callchains on the syscall exit path.
182 173
183 --max-events=N:: <<
184 Stop after processing N events. Note t <<
185 only at exit time or when a syscall is <<
186 option is equivalent to the number of <<
187 <<
188 --switch-on EVENT_NAME:: <<
189 Only consider events after this event <<
190 <<
191 --switch-off EVENT_NAME:: <<
192 Stop considering events after this eve <<
193 <<
194 --show-on-off-events:: <<
195 Show the --switch-on/off events too. <<
196 <<
197 --max-stack:: 174 --max-stack::
198 Set the stack depth limit when parsing 175 Set the stack depth limit when parsing the callchain, anything
199 beyond the specified depth will be ign 176 beyond the specified depth will be ignored. Note that at this point
200 this is just about the presentation pa 177 this is just about the presentation part, i.e. the kernel is still
201 not limiting, the overhead of callchai 178 not limiting, the overhead of callchains needs to be set via the
202 knobs in --call-graph dwarf. 179 knobs in --call-graph dwarf.
203 180
204 Implies '--call-graph dwarf' when --ca 181 Implies '--call-graph dwarf' when --call-graph not present on the
205 command line, on systems where DWARF u 182 command line, on systems where DWARF unwinding was built in.
206 183
207 Default: /proc/sys/kernel/perf_event_m 184 Default: /proc/sys/kernel/perf_event_max_stack when present for
208 live sessions (without --inpu 185 live sessions (without --input/-i), 127 otherwise.
209 186
210 --min-stack:: 187 --min-stack::
211 Set the stack depth limit when parsing 188 Set the stack depth limit when parsing the callchain, anything
212 below the specified depth will be igno 189 below the specified depth will be ignored. Disabled by default.
213 190
214 Implies '--call-graph dwarf' when --ca 191 Implies '--call-graph dwarf' when --call-graph not present on the
215 command line, on systems where DWARF u 192 command line, on systems where DWARF unwinding was built in.
216 193
217 --print-sample:: 194 --print-sample::
218 Print the PERF_RECORD_SAMPLE PERF_SAMP 195 Print the PERF_RECORD_SAMPLE PERF_SAMPLE_ info for the
219 raw_syscalls:sys_{enter,exit} tracepoi 196 raw_syscalls:sys_{enter,exit} tracepoints, for debugging.
220 197
221 --proc-map-timeout:: 198 --proc-map-timeout::
222 When processing pre-existing threads / 199 When processing pre-existing threads /proc/XXX/mmap, it may take a long time,
223 because the file may be huge. A time o 200 because the file may be huge. A time out is needed in such cases.
224 This option sets the time out limit. T 201 This option sets the time out limit. The default value is 500 ms.
225 202
226 --sort-events:: <<
227 Do sorting on batches of events, use w <<
228 may happen, for instance, when a threa <<
229 while processing a syscall. <<
230 <<
231 --libtraceevent_print:: <<
232 Use libtraceevent to print tracepoint <<
233 the same beautifiers used in the strac <<
234 tracepoint arguments. <<
235 <<
236 --map-dump:: <<
237 Dump BPF maps setup by events passed v <<
238 living in tools/perf/examples/bpf/augm <<
239 dumps just boolean map values and inte <<
240 by default and use BTF when available, <<
241 printing using the existing 'perf trac <<
242 arguments to strings (pid to comm, sys <<
243 <<
244 <<
245 PAGEFAULTS 203 PAGEFAULTS
246 ---------- 204 ----------
247 205
248 When tracing pagefaults, the format of the tra 206 When tracing pagefaults, the format of the trace is as follows:
249 207
250 <min|maj>fault [<ip.symbol>+<ip.offset>] => <ad 208 <min|maj>fault [<ip.symbol>+<ip.offset>] => <addr.dso@addr.offset> (<map type><addr level>).
251 209
252 - min/maj indicates whether fault event is min 210 - min/maj indicates whether fault event is minor or major;
253 - ip.symbol shows symbol for instruction point 211 - ip.symbol shows symbol for instruction pointer (the code that generated the
254 fault); if no debug symbols available, perf 212 fault); if no debug symbols available, perf trace will print raw IP;
255 - addr.dso shows DSO for the faulted address; 213 - addr.dso shows DSO for the faulted address;
256 - map type is either 'd' for non-executable ma 214 - map type is either 'd' for non-executable maps or 'x' for executable maps;
257 - addr level is either 'k' for kernel dso or ' 215 - addr level is either 'k' for kernel dso or '.' for user dso.
258 216
259 For symbols resolution you may need to install 217 For symbols resolution you may need to install debugging symbols.
260 218
261 Please be aware that duration is currently alw 219 Please be aware that duration is currently always 0 and doesn't reflect actual
262 time it took for fault to be handled! 220 time it took for fault to be handled!
263 221
264 When --verbose specified, perf trace tries to 222 When --verbose specified, perf trace tries to print all available information
265 for both IP and fault address in the form of d 223 for both IP and fault address in the form of dso@symbol+offset.
266 224
267 EXAMPLES 225 EXAMPLES
268 -------- 226 --------
269 227
270 Trace only major pagefaults: 228 Trace only major pagefaults:
271 229
272 $ perf trace --no-syscalls -F 230 $ perf trace --no-syscalls -F
273 231
274 Trace syscalls, major and minor pagefaults: 232 Trace syscalls, major and minor pagefaults:
275 233
276 $ perf trace -F all 234 $ perf trace -F all
277 235
278 1416.547 ( 0.000 ms): python/20235 majfault 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.)
279 237
280 As you can see, there was major pagefault in 238 As you can see, there was major pagefault in python process, from
281 CRYPTO_push_info_ routine which faulted some 239 CRYPTO_push_info_ routine which faulted somewhere in libcrypto.so.
282 <<
283 Trace the first 4 open, openat or open_by_hand <<
284 <<
285 $ perf trace -e open* --max-events 4 <<
286 [root@jouet perf]# trace -e open* --max-even <<
287 2272.992 ( 0.037 ms): gnome-shell/1370 opena <<
288 2277.481 ( 0.139 ms): gnome-shell/3039 opena <<
289 3026.398 ( 0.076 ms): gnome-shell/3039 opena <<
290 4294.665 ( 0.015 ms): sed/15879 openat(dfd: <<
291 $ <<
292 <<
293 Trace the first minor page fault when running <<
294 <<
295 # perf trace -F min --max-stack=7 --max-even <<
296 0.000 ( 0.000 ms): sleep/18006 minfault [ <<
297 __clear <<
298 load_el <<
299 search_ <<
300 __do_ex <<
301 __x64_s <<
302 do_sysc <<
303 entry_S <<
304 # <<
305 <<
306 Trace the next min page page fault to take pla <<
307 <<
308 # perf trace -F min --call-graph=dwarf --max <<
309 0.000 ( 0.000 ms): Web Content/17136 minf <<
310 js::gc: <<
311 js::gc: <<
312 js::gc: <<
313 js::gc: <<
314 js::gc: <<
315 js::gc: <<
316 js::gc: <<
317 js::All <<
318 js::All <<
319 JSThinI <<
320 Allocat <<
321 js::Con <<
322 [0x18b2 <<
323 # <<
324 <<
325 Trace the next two sched:sched_switch events, <<
326 next block:*_unplug and the next three net:*de <<
327 with a backtrace of at most 16 entries, system <<
328 <<
329 # perf trace -e sched:*switch/nr=2/,block:*_ <<
330 0.000 :0/0 sched:sched_switch:swapper/2:0 <<
331 0.015 rcu_sched/10 sched:sched_switch:rcu <<
332 254.198 irq/50-iwlwifi/680 net:net_dev_queu <<
333 __dev_q <<
334 273.977 :0/0 net:net_dev_queue:dev=wlp3s0 s <<
335 __dev_q <<
336 274.007 :0/0 net:net_dev_queue:dev=wlp3s0 s <<
337 __dev_q <<
338 2930.140 kworker/u16:58/2722 block:block_plu <<
339 2930.162 kworker/u16:58/2722 block:block_unp <<
340 4466.094 jbd2/dm-2-8/748 block:block_plug:[j <<
341 8050.123 kworker/u16:30/2694 block:block_plu <<
342 8050.271 kworker/u16:30/2694 block:block_plu <<
343 # <<
344 240
345 SEE ALSO 241 SEE ALSO
346 -------- 242 --------
347 linkperf:perf-record[1], linkperf:perf-script[ 243 linkperf:perf-record[1], linkperf:perf-script[1]
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