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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]
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 symbolic or raw PMU event followed by an optional colon
37 and a list of event modifiers, e.g., cpu-cycles:p. See the
38 linkperf:perf-list[1] man page for details on event modifiers.
39
40 - a symbolically formed PMU event like 'pmu/param1=0x3,param2/' where
41 'param1', 'param2', etc are defined as formats for the PMU in
42 /sys/bus/event_source/devices/<pmu>/format/*.
43
44 - a symbolically formed event like 'pmu/config=M,config1=N,config3=K/'
45
46 where M, N, K are numbers (in decimal, hex, octal format). Acceptable
47 values for each of 'config', 'config1' and 'config2' are defined by
48 corresponding entries in /sys/bus/event_source/devices/<pmu>/format/*
49 param1 and param2 are defined as formats for the PMU in:
50 /sys/bus/event_source/devices/<pmu>/format/*
51
52 There are also some parameters which are not defined in .../<pmu>/format/*.
53 These params can be used to overload default config values per event.
54 Here are some common parameters:
55 - 'period': Set event sampling period
56 - 'freq': Set event sampling frequency
57 - 'time': Disable/enable time stamping. Acceptable values are 1 for
58 enabling time stamping. 0 for disabling time stamping.
59 The default is 1.
60 - 'call-graph': Disable/enable callgraph. Acceptable str are "fp" for
61 FP mode, "dwarf" for DWARF mode, "lbr" for LBR mode and
62 "no" for disable callgraph.
63 - 'stack-size': user stack size for dwarf mode
64 - 'name' : User defined event name. Single quotes (') may be used to
65 escape symbols in the name from parsing by shell and tool
66 like this: name=\'CPU_CLK_UNHALTED.THREAD:cmask=0x1\'.
67 - 'aux-output': Generate AUX records instead of events. This requires
68 that an AUX area event is also provided.
69 - 'aux-sample-size': Set sample size for AUX area sampling. If the
70 '--aux-sample' option has been used, set aux-sample-size=0 to disable
71 AUX area sampling for the event.
72
73 See the linkperf:perf-list[1] man page for more parameters.
74
75 Note: If user explicitly sets options which conflict with the params,
76 the value set by the parameters will be overridden.
77
78 Also not defined in .../<pmu>/format/* are PMU driver specific
79 configuration parameters. Any configuration parameter preceded by
80 the letter '@' is not interpreted in user space and sent down directly
81 to the PMU driver. For example:
82
83 perf record -e some_event/@cfg1,@cfg2=config/ ...
84
85 will see 'cfg1' and 'cfg2=config' pushed to the PMU driver associated
86 with the event for further processing. There is no restriction on
87 what the configuration parameters are, as long as their semantic is
88 understood and supported by the PMU driver.
89
90 - a hardware breakpoint event in the form of '\mem:addr[/len][:access]'
91 where addr is the address in memory you want to break in.
92 Access is the memory access type (read, write, execute) it can
93 be passed as follows: '\mem:addr[:[r][w][x]]'. len is the range,
94 number of bytes from specified addr, which the breakpoint will cover.
95 If you want to profile read-write accesses in 0x1000, just set
96 'mem:0x1000:rw'.
97 If you want to profile write accesses in [0x1000~1008), just set
98 'mem:0x1000/8:w'.
99
100 - a BPF source file (ending in .c) or a precompiled object file (ending
101 in .o) selects one or more BPF events.
102 The BPF program can attach to various perf events based on the ELF section
103 names.
104
105 When processing a '.c' file, perf searches an installed LLVM to compile it
106 into an object file first. Optional clang options can be passed via the
107 '--clang-opt' command line option, e.g.:
108
109 perf record --clang-opt "-DLINUX_VERSION_CODE=0x50000" \
110 -e tests/bpf-script-example.c
111
112 Note: '--clang-opt' must be placed before '--event/-e'.
113
114 - a group of events surrounded by a pair of brace ("{event1,event2,...}").
115 Each event is separated by commas and the group should be quoted to
116 prevent the shell interpretation. You also need to use --group on
117 "perf report" to view group events together.
118
119--filter=<filter>::
120 Event filter. This option should follow an event selector (-e) which
121 selects either tracepoint event(s) or a hardware trace PMU
122 (e.g. Intel PT or CoreSight).
123
124 - tracepoint filters
125
126 In the case of tracepoints, multiple '--filter' options are combined
127 using '&&'.
128
129 - address filters
130
131 A hardware trace PMU advertises its ability to accept a number of
132 address filters by specifying a non-zero value in
133 /sys/bus/event_source/devices/<pmu>/nr_addr_filters.
134
135 Address filters have the format:
136
137 filter|start|stop|tracestop <start> [/ <size>] [@<file name>]
138
139 Where:
140 - 'filter': defines a region that will be traced.
141 - 'start': defines an address at which tracing will begin.
142 - 'stop': defines an address at which tracing will stop.
143 - 'tracestop': defines a region in which tracing will stop.
144
145 <file name> is the name of the object file, <start> is the offset to the
146 code to trace in that file, and <size> is the size of the region to
147 trace. 'start' and 'stop' filters need not specify a <size>.
148
149 If no object file is specified then the kernel is assumed, in which case
150 the start address must be a current kernel memory address.
151
152 <start> can also be specified by providing the name of a symbol. If the
153 symbol name is not unique, it can be disambiguated by inserting #n where
154 'n' selects the n'th symbol in address order. Alternately #0, #g or #G
155 select only a global symbol. <size> can also be specified by providing
156 the name of a symbol, in which case the size is calculated to the end
157 of that symbol. For 'filter' and 'tracestop' filters, if <size> is
158 omitted and <start> is a symbol, then the size is calculated to the end
159 of that symbol.
160
161 If <size> is omitted and <start> is '*', then the start and size will
162 be calculated from the first and last symbols, i.e. to trace the whole
163 file.
164
165 If symbol names (or '*') are provided, they must be surrounded by white
166 space.
167
168 The filter passed to the kernel is not necessarily the same as entered.
169 To see the filter that is passed, use the -v option.
170
171 The kernel may not be able to configure a trace region if it is not
172 within a single mapping. MMAP events (or /proc/<pid>/maps) can be
173 examined to determine if that is a possibility.
174
175 Multiple filters can be separated with space or comma.
176
177--exclude-perf::
178 Don't record events issued by perf itself. This option should follow
179 an event selector (-e) which selects tracepoint event(s). It adds a
180 filter expression 'common_pid != $PERFPID' to filters. If other
181 '--filter' exists, the new filter expression will be combined with
182 them by '&&'.
183
184-a::
185--all-cpus::
186 System-wide collection from all CPUs (default if no target is specified).
187
188-p::
189--pid=::
190 Record events on existing process ID (comma separated list).
191
192-t::
193--tid=::
194 Record events on existing thread ID (comma separated list).
195 This option also disables inheritance by default. Enable it by adding
196 --inherit.
197
198-u::
199--uid=::
200 Record events in threads owned by uid. Name or number.
201
202-r::
203--realtime=::
204 Collect data with this RT SCHED_FIFO priority.
205
206--no-buffering::
207 Collect data without buffering.
208
209-c::
210--count=::
211 Event period to sample.
212
213-o::
214--output=::
215 Output file name.
216
217-i::
218--no-inherit::
219 Child tasks do not inherit counters.
220
221-F::
222--freq=::
223 Profile at this frequency. Use 'max' to use the currently maximum
224 allowed frequency, i.e. the value in the kernel.perf_event_max_sample_rate
225 sysctl. Will throttle down to the currently maximum allowed frequency.
226 See --strict-freq.
227
228--strict-freq::
229 Fail if the specified frequency can't be used.
230
231-m::
232--mmap-pages=::
233 Number of mmap data pages (must be a power of two) or size
234 specification with appended unit character - B/K/M/G. The
235 size is rounded up to have nearest pages power of two value.
236 Also, by adding a comma, the number of mmap pages for AUX
237 area tracing can be specified.
238
239--group::
240 Put all events in a single event group. This precedes the --event
241 option and remains only for backward compatibility. See --event.
242
243-g::
244 Enables call-graph (stack chain/backtrace) recording for both
245 kernel space and user space.
246
247--call-graph::
248 Setup and enable call-graph (stack chain/backtrace) recording,
249 implies -g. Default is "fp" (for user space).
250
251 The unwinding method used for kernel space is dependent on the
252 unwinder used by the active kernel configuration, i.e
253 CONFIG_UNWINDER_FRAME_POINTER (fp) or CONFIG_UNWINDER_ORC (orc)
254
255 Any option specified here controls the method used for user space.
256
257 Valid options are "fp" (frame pointer), "dwarf" (DWARF's CFI -
258 Call Frame Information) or "lbr" (Hardware Last Branch Record
259 facility).
260
261 In some systems, where binaries are build with gcc
262 --fomit-frame-pointer, using the "fp" method will produce bogus
263 call graphs, using "dwarf", if available (perf tools linked to
264 the libunwind or libdw library) should be used instead.
265 Using the "lbr" method doesn't require any compiler options. It
266 will produce call graphs from the hardware LBR registers. The
267 main limitation is that it is only available on new Intel
268 platforms, such as Haswell. It can only get user call chain. It
269 doesn't work with branch stack sampling at the same time.
270
271 When "dwarf" recording is used, perf also records (user) stack dump
272 when sampled. Default size of the stack dump is 8192 (bytes).
273 User can change the size by passing the size after comma like
274 "--call-graph dwarf,4096".
275
276-q::
277--quiet::
278 Don't print any message, useful for scripting.
279
280-v::
281--verbose::
282 Be more verbose (show counter open errors, etc).
283
284-s::
285--stat::
286 Record per-thread event counts. Use it with 'perf report -T' to see
287 the values.
288
289-d::
290--data::
291 Record the sample virtual addresses.
292
293--phys-data::
294 Record the sample physical addresses.
295
296-T::
297--timestamp::
298 Record the sample timestamps. Use it with 'perf report -D' to see the
299 timestamps, for instance.
300
301-P::
302--period::
303 Record the sample period.
304
305--sample-cpu::
306 Record the sample cpu.
307
308-n::
309--no-samples::
310 Don't sample.
311
312-R::
313--raw-samples::
314Collect raw sample records from all opened counters (default for tracepoint counters).
315
316-C::
317--cpu::
318Collect samples only on the list of CPUs provided. Multiple CPUs can be provided as a
319comma-separated list with no space: 0,1. Ranges of CPUs are specified with -: 0-2.
320In per-thread mode with inheritance mode on (default), samples are captured only when
321the thread executes on the designated CPUs. Default is to monitor all CPUs.
322
323-B::
324--no-buildid::
325Do not save the build ids of binaries in the perf.data files. This skips
326post processing after recording, which sometimes makes the final step in
327the recording process to take a long time, as it needs to process all
328events looking for mmap records. The downside is that it can misresolve
329symbols if the workload binaries used when recording get locally rebuilt
330or upgraded, because the only key available in this case is the
331pathname. You can also set the "record.build-id" config variable to
332'skip to have this behaviour permanently.
333
334-N::
335--no-buildid-cache::
336Do not update the buildid cache. This saves some overhead in situations
337where the information in the perf.data file (which includes buildids)
338is sufficient. You can also set the "record.build-id" config variable to
339'no-cache' to have the same effect.
340
341-G name,...::
342--cgroup name,...::
343monitor only in the container (cgroup) called "name". This option is available only
344in per-cpu mode. The cgroup filesystem must be mounted. All threads belonging to
345container "name" are monitored when they run on the monitored CPUs. Multiple cgroups
346can be provided. Each cgroup is applied to the corresponding event, i.e., first cgroup
347to first event, second cgroup to second event and so on. It is possible to provide
348an empty cgroup (monitor all the time) using, e.g., -G foo,,bar. Cgroups must have
349corresponding events, i.e., they always refer to events defined earlier on the command
350line. If the user wants to track multiple events for a specific cgroup, the user can
351use '-e e1 -e e2 -G foo,foo' or just use '-e e1 -e e2 -G foo'.
352
353If wanting to monitor, say, 'cycles' for a cgroup and also for system wide, this
354command line can be used: 'perf stat -e cycles -G cgroup_name -a -e cycles'.
355
356-b::
357--branch-any::
358Enable taken branch stack sampling. Any type of taken branch may be sampled.
359This is a shortcut for --branch-filter any. See --branch-filter for more infos.
360
361-j::
362--branch-filter::
363Enable taken branch stack sampling. Each sample captures a series of consecutive
364taken branches. The number of branches captured with each sample depends on the
365underlying hardware, the type of branches of interest, and the executed code.
366It is possible to select the types of branches captured by enabling filters. The
367following filters are defined:
368
369 - any: any type of branches
370 - any_call: any function call or system call
371 - any_ret: any function return or system call return
372 - ind_call: any indirect branch
373 - call: direct calls, including far (to/from kernel) calls
374 - u: only when the branch target is at the user level
375 - k: only when the branch target is in the kernel
376 - hv: only when the target is at the hypervisor level
377 - in_tx: only when the target is in a hardware transaction
378 - no_tx: only when the target is not in a hardware transaction
379 - abort_tx: only when the target is a hardware transaction abort
380 - cond: conditional branches
381 - save_type: save branch type during sampling in case binary is not available later
382
383+
384The option requires at least one branch type among any, any_call, any_ret, ind_call, cond.
385The privilege levels may be omitted, in which case, the privilege levels of the associated
386event are applied to the branch filter. Both kernel (k) and hypervisor (hv) privilege
387levels are subject to permissions. When sampling on multiple events, branch stack sampling
388is enabled for all the sampling events. The sampled branch type is the same for all events.
389The various filters must be specified as a comma separated list: --branch-filter any_ret,u,k
390Note that this feature may not be available on all processors.
391
392--weight::
393Enable weightened sampling. An additional weight is recorded per sample and can be
394displayed with the weight and local_weight sort keys. This currently works for TSX
395abort events and some memory events in precise mode on modern Intel CPUs.
396
397--namespaces::
398Record events of type PERF_RECORD_NAMESPACES. This enables 'cgroup_id' sort key.
399
400--all-cgroups::
401Record events of type PERF_RECORD_CGROUP. This enables 'cgroup' sort key.
402
403--transaction::
404Record transaction flags for transaction related events.
405
406--per-thread::
407Use per-thread mmaps. By default per-cpu mmaps are created. This option
408overrides that and uses per-thread mmaps. A side-effect of that is that
409inheritance is automatically disabled. --per-thread is ignored with a warning
410if combined with -a or -C options.
411
412-D::
413--delay=::
414After starting the program, wait msecs before measuring (-1: start with events
415disabled). This is useful to filter out the startup phase of the program, which
416is often very different.
417
418-I::
419--intr-regs::
420Capture machine state (registers) at interrupt, i.e., on counter overflows for
421each sample. List of captured registers depends on the architecture. This option
422is off by default. It is possible to select the registers to sample using their
423symbolic names, e.g. on x86, ax, si. To list the available registers use
424--intr-regs=\?. To name registers, pass a comma separated list such as
425--intr-regs=ax,bx. The list of register is architecture dependent.
426
427--user-regs::
428Similar to -I, but capture user registers at sample time. To list the available
429user registers use --user-regs=\?.
430
431--running-time::
432Record running and enabled time for read events (:S)
433
434-k::
435--clockid::
436Sets the clock id to use for the various time fields in the perf_event_type
437records. See clock_gettime(). In particular CLOCK_MONOTONIC and
438CLOCK_MONOTONIC_RAW are supported, some events might also allow
439CLOCK_BOOTTIME, CLOCK_REALTIME and CLOCK_TAI.
440
441-S::
442--snapshot::
443Select AUX area tracing Snapshot Mode. This option is valid only with an
444AUX area tracing event. Optionally, certain snapshot capturing parameters
445can be specified in a string that follows this option:
446 'e': take one last snapshot on exit; guarantees that there is at least one
447 snapshot in the output file;
448 <size>: if the PMU supports this, specify the desired snapshot size.
449
450In Snapshot Mode trace data is captured only when signal SIGUSR2 is received
451and on exit if the above 'e' option is given.
452
453--aux-sample[=OPTIONS]::
454Select AUX area sampling. At least one of the events selected by the -e option
455must be an AUX area event. Samples on other events will be created containing
456data from the AUX area. Optionally sample size may be specified, otherwise it
457defaults to 4KiB.
458
459--proc-map-timeout::
460When processing pre-existing threads /proc/XXX/mmap, it may take a long time,
461because the file may be huge. A time out is needed in such cases.
462This option sets the time out limit. The default value is 500 ms.
463
464--switch-events::
465Record context switch events i.e. events of type PERF_RECORD_SWITCH or
466PERF_RECORD_SWITCH_CPU_WIDE. In some cases (e.g. Intel PT or CoreSight)
467switch events will be enabled automatically, which can be suppressed by
468by the option --no-switch-events.
469
470--clang-path=PATH::
471Path to clang binary to use for compiling BPF scriptlets.
472(enabled when BPF support is on)
473
474--clang-opt=OPTIONS::
475Options passed to clang when compiling BPF scriptlets.
476(enabled when BPF support is on)
477
478--vmlinux=PATH::
479Specify vmlinux path which has debuginfo.
480(enabled when BPF prologue is on)
481
482--buildid-all::
483Record build-id of all DSOs regardless whether it's actually hit or not.
484
485--aio[=n]::
486Use <n> control blocks in asynchronous (Posix AIO) trace writing mode (default: 1, max: 4).
487Asynchronous mode is supported only when linking Perf tool with libc library
488providing implementation for Posix AIO API.
489
490--affinity=mode::
491Set affinity mask of trace reading thread according to the policy defined by 'mode' value:
492 node - thread affinity mask is set to NUMA node cpu mask of the processed mmap buffer
493 cpu - thread affinity mask is set to cpu of the processed mmap buffer
494
495--mmap-flush=number::
496
497Specify minimal number of bytes that is extracted from mmap data pages and
498processed for output. One can specify the number using B/K/M/G suffixes.
499
500The maximal allowed value is a quarter of the size of mmaped data pages.
501
502The default option value is 1 byte which means that every time that the output
503writing thread finds some new data in the mmaped buffer the data is extracted,
504possibly compressed (-z) and written to the output, perf.data or pipe.
505
506Larger data chunks are compressed more effectively in comparison to smaller
507chunks so extraction of larger chunks from the mmap data pages is preferable
508from the perspective of output size reduction.
509
510Also at some cases executing less output write syscalls with bigger data size
511can take less time than executing more output write syscalls with smaller data
512size thus lowering runtime profiling overhead.
513
514-z::
515--compression-level[=n]::
516Produce compressed trace using specified level n (default: 1 - fastest compression,
51722 - smallest trace)
518
519--all-kernel::
520Configure all used events to run in kernel space.
521
522--all-user::
523Configure all used events to run in user space.
524
525--kernel-callchains::
526Collect callchains only from kernel space. I.e. this option sets
527perf_event_attr.exclude_callchain_user to 1.
528
529--user-callchains::
530Collect callchains only from user space. I.e. this option sets
531perf_event_attr.exclude_callchain_kernel to 1.
532
533Don't use both --kernel-callchains and --user-callchains at the same time or no
534callchains will be collected.
535
536--timestamp-filename
537Append timestamp to output file name.
538
539--timestamp-boundary::
540Record timestamp boundary (time of first/last samples).
541
542--switch-output[=mode]::
543Generate multiple perf.data files, timestamp prefixed, switching to a new one
544based on 'mode' value:
545 "signal" - when receiving a SIGUSR2 (default value) or
546 <size> - when reaching the size threshold, size is expected to
547 be a number with appended unit character - B/K/M/G
548 <time> - when reaching the time threshold, size is expected to
549 be a number with appended unit character - s/m/h/d
550
551 Note: the precision of the size threshold hugely depends
552 on your configuration - the number and size of your ring
553 buffers (-m). It is generally more precise for higher sizes
554 (like >5M), for lower values expect different sizes.
555
556A possible use case is to, given an external event, slice the perf.data file
557that gets then processed, possibly via a perf script, to decide if that
558particular perf.data snapshot should be kept or not.
559
560Implies --timestamp-filename, --no-buildid and --no-buildid-cache.
561The reason for the latter two is to reduce the data file switching
562overhead. You can still switch them on with:
563
564 --switch-output --no-no-buildid --no-no-buildid-cache
565
566--switch-output-event::
567Events that will cause the switch of the perf.data file, auto-selecting
568--switch-output=signal, the results are similar as internally the side band
569thread will also send a SIGUSR2 to the main one.
570
571Uses the same syntax as --event, it will just not be recorded, serving only to
572switch the perf.data file as soon as the --switch-output event is processed by
573a separate sideband thread.
574
575This sideband thread is also used to other purposes, like processing the
576PERF_RECORD_BPF_EVENT records as they happen, asking the kernel for extra BPF
577information, etc.
578
579--switch-max-files=N::
580
581When rotating perf.data with --switch-output, only keep N files.
582
583--dry-run::
584Parse options then exit. --dry-run can be used to detect errors in cmdline
585options.
586
587'perf record --dry-run -e' can act as a BPF script compiler if llvm.dump-obj
588in config file is set to true.
589
590--tail-synthesize::
591Instead of collecting non-sample events (for example, fork, comm, mmap) at
592the beginning of record, collect them during finalizing an output file.
593The collected non-sample events reflects the status of the system when
594record is finished.
595
596--overwrite::
597Makes all events use an overwritable ring buffer. An overwritable ring
598buffer works like a flight recorder: when it gets full, the kernel will
599overwrite the oldest records, that thus will never make it to the
600perf.data file.
601
602When '--overwrite' and '--switch-output' are used perf records and drops
603events until it receives a signal, meaning that something unusual was
604detected that warrants taking a snapshot of the most current events,
605those fitting in the ring buffer at that moment.
606
607'overwrite' attribute can also be set or canceled for an event using
608config terms. For example: 'cycles/overwrite/' and 'instructions/no-overwrite/'.
609
610Implies --tail-synthesize.
611
612--kcore::
613Make a copy of /proc/kcore and place it into a directory with the perf data file.
614
615--max-size=<size>::
616Limit the sample data max size, <size> is expected to be a number with
617appended unit character - B/K/M/G
618
619--num-thread-synthesize::
620 The number of threads to run when synthesizing events for existing processes.
621 By default, the number of threads equals 1.
622
623ifdef::HAVE_LIBPFM[]
624--pfm-events events::
625Select a PMU event using libpfm4 syntax (see http://perfmon2.sf.net)
626including support for event filters. For example '--pfm-events
627inst_retired:any_p:u:c=1:i'. More than one event can be passed to the
628option using the comma separator. Hardware events and generic hardware
629events cannot be mixed together. The latter must be used with the -e
630option. The -e option and this one can be mixed and matched. Events
631can be grouped using the {} notation.
632endif::HAVE_LIBPFM[]
633
634--control fd:ctl-fd[,ack-fd]
635Listen on ctl-fd descriptor for command to control measurement ('enable': enable events,
636'disable': disable events). Measurements can be started with events disabled using
637--delay=-1 option. Optionally send control command completion ('ack\n') to ack-fd descriptor
638to synchronize with the controlling process. Example of bash shell script to enable and
639disable events during measurements:
640
641#!/bin/bash
642
643ctl_dir=/tmp/
644
645ctl_fifo=${ctl_dir}perf_ctl.fifo
646test -p ${ctl_fifo} && unlink ${ctl_fifo}
647mkfifo ${ctl_fifo}
648exec {ctl_fd}<>${ctl_fifo}
649
650ctl_ack_fifo=${ctl_dir}perf_ctl_ack.fifo
651test -p ${ctl_ack_fifo} && unlink ${ctl_ack_fifo}
652mkfifo ${ctl_ack_fifo}
653exec {ctl_fd_ack}<>${ctl_ack_fifo}
654
655perf record -D -1 -e cpu-cycles -a \
656 --control fd:${ctl_fd},${ctl_fd_ack} \
657 -- sleep 30 &
658perf_pid=$!
659
660sleep 5 && echo 'enable' >&${ctl_fd} && read -u ${ctl_fd_ack} e1 && echo "enabled(${e1})"
661sleep 10 && echo 'disable' >&${ctl_fd} && read -u ${ctl_fd_ack} d1 && echo "disabled(${d1})"
662
663exec {ctl_fd_ack}>&-
664unlink ${ctl_ack_fifo}
665
666exec {ctl_fd}>&-
667unlink ${ctl_fifo}
668
669wait -n ${perf_pid}
670exit $?
671
672
673SEE ALSO
674--------
675linkperf:perf-stat[1], linkperf:perf-list[1], linkperf:perf-intel-pt[1]