1PERF-RECORD(1) perf Manual PERF-RECORD(1)
2
6 perf-record - Run a command and record its profile into perf.data
7
9 perf record [-e <EVENT> | --event=EVENT] [-a] <command>
10 perf record [-e <EVENT> | --event=EVENT] [-a] -- <command> [<options>]
11
13 This command runs a command and gathers a performance counter profile
14 from it, into perf.data - without displaying anything.
15 This file can then be inspected later on, using perf report.
17
19 <command>...
20 Any command you can specify in a shell.
21 -e, --event=
23 Select the PMU event. Selection can be:
24 • a symbolic event name (use perf list to list all events)
26 • a raw PMU event in the form of rN where N is a hexadecimal
28 value that represents the raw register encoding with the layout
29 of the event control registers as described by entries in
30 /sys/bus/event_source/devices/cpu/format/*.
31 • a symbolic or raw PMU event followed by an optional colon and a
33 list of event modifiers, e.g., cpu-cycles:p. See the perf-
34 list(1) man page for details on event modifiers.
35 • a symbolically formed PMU event like pmu/param1=0x3,param2/
37 where param1, param2, etc are defined as formats for the PMU in
38 /sys/bus/event_source/devices/<pmu>/format/*.
39 • a symbolically formed event like
41 pmu/config=M,config1=N,config3=K/
42 where M, N, K are numbers (in decimal, hex, octal format). Acceptable
44 values for each of 'config', 'config1' and 'config2' are defined by
45 corresponding entries in /sys/bus/event_source/devices/<pmu>/format/*
46 param1 and param2 are defined as formats for the PMU in:
47 /sys/bus/event_source/devices/<pmu>/format/*
48 There are also some parameters which are not defined in .../<pmu>/format/*.
50 These params can be used to overload default config values per event.
51 Here are some common parameters:
52 - 'period': Set event sampling period
53 - 'freq': Set event sampling frequency
54 - 'time': Disable/enable time stamping. Acceptable values are 1 for
55 enabling time stamping. 0 for disabling time stamping.
56 The default is 1.
57 - 'call-graph': Disable/enable callgraph. Acceptable str are "fp" for
58 FP mode, "dwarf" for DWARF mode, "lbr" for LBR mode and
59 "no" for disable callgraph.
60 - 'stack-size': user stack size for dwarf mode
61 - 'name' : User defined event name. Single quotes (') may be used to
62 escape symbols in the name from parsing by shell and tool
63 like this: name=\'CPU_CLK_UNHALTED.THREAD:cmask=0x1\'.
64 - 'aux-output': Generate AUX records instead of events. This requires
65 that an AUX area event is also provided.
66 - 'aux-sample-size': Set sample size for AUX area sampling. If the
67 '--aux-sample' option has been used, set aux-sample-size=0 to disable
68 AUX area sampling for the event.
69 See the linkperf:perf-list[1] man page for more parameters.
71 Note: If user explicitly sets options which conflict with the params,
73 the value set by the parameters will be overridden.
74 Also not defined in .../<pmu>/format/* are PMU driver specific
76 configuration parameters. Any configuration parameter preceded by
77 the letter '@' is not interpreted in user space and sent down directly
78 to the PMU driver. For example:
79 perf record -e some_event/@cfg1,@cfg2=config/ ...
81 will see 'cfg1' and 'cfg2=config' pushed to the PMU driver associated
83 with the event for further processing. There is no restriction on
84 what the configuration parameters are, as long as their semantic is
85 understood and supported by the PMU driver.
86 • a hardware breakpoint event in the form of
88 \mem:addr[/len][:access] where addr is the address in memory
89 you want to break in. Access is the memory access type (read,
90 write, execute) it can be passed as follows:
91 \mem:addr[:[r][w][x]]. len is the range, number of bytes from
92 specified addr, which the breakpoint will cover. If you want to
93 profile read-write accesses in 0x1000, just set mem:0x1000:rw.
94 If you want to profile write accesses in [0x1000~1008), just
95 set mem:0x1000/8:w.
96 • a BPF source file (ending in .c) or a precompiled object file
98 (ending in .o) selects one or more BPF events. The BPF program
99 can attach to various perf events based on the ELF section
100 names.
101 When processing a '.c' file, perf searches an installed LLVM to compile it
103 into an object file first. Optional clang options can be passed via the
104 '--clang-opt' command line option, e.g.:
105 perf record --clang-opt "-DLINUX_VERSION_CODE=0x50000" \
107 -e tests/bpf-script-example.c
108 Note: '--clang-opt' must be placed before '--event/-e'.
110 • a group of events surrounded by a pair of brace
112 ("{event1,event2,...}"). Each event is separated by commas and
113 the group should be quoted to prevent the shell interpretation.
114 You also need to use --group on "perf report" to view group
115 events together.
116 --filter=<filter>
118 Event filter. This option should follow an event selector (-e)
119 which selects either tracepoint event(s) or a hardware trace PMU
120 (e.g. Intel PT or CoreSight).
121 • tracepoint filters
123 In the case of tracepoints, multiple '--filter' options are combined
125 using '&&'.
126 • address filters
128 A hardware trace PMU advertises its ability to accept a number of
130 address filters by specifying a non-zero value in
131 /sys/bus/event_source/devices/<pmu>/nr_addr_filters.
132 Address filters have the format:
134 filter|start|stop|tracestop <start> [/ <size>] [@<file name>]
136 Where:
138 - 'filter': defines a region that will be traced.
139 - 'start': defines an address at which tracing will begin.
140 - 'stop': defines an address at which tracing will stop.
141 - 'tracestop': defines a region in which tracing will stop.
142 <file name> is the name of the object file, <start> is the offset to the
144 code to trace in that file, and <size> is the size of the region to
145 trace. 'start' and 'stop' filters need not specify a <size>.
146 If no object file is specified then the kernel is assumed, in which case
148 the start address must be a current kernel memory address.
149 <start> can also be specified by providing the name of a symbol. If the
151 symbol name is not unique, it can be disambiguated by inserting #n where
152 'n' selects the n'th symbol in address order. Alternately #0, #g or #G
153 select only a global symbol. <size> can also be specified by providing
154 the name of a symbol, in which case the size is calculated to the end
155 of that symbol. For 'filter' and 'tracestop' filters, if <size> is
156 omitted and <start> is a symbol, then the size is calculated to the end
157 of that symbol.
158 If <size> is omitted and <start> is '*', then the start and size will
160 be calculated from the first and last symbols, i.e. to trace the whole
161 file.
162 If symbol names (or '*') are provided, they must be surrounded by white
164 space.
165 The filter passed to the kernel is not necessarily the same as entered.
167 To see the filter that is passed, use the -v option.
168 The kernel may not be able to configure a trace region if it is not
170 within a single mapping. MMAP events (or /proc/<pid>/maps) can be
171 examined to determine if that is a possibility.
172 Multiple filters can be separated with space or comma.
174 --exclude-perf
176 Don’t record events issued by perf itself. This option should
177 follow an event selector (-e) which selects tracepoint event(s). It
178 adds a filter expression common_pid != $PERFPID to filters. If
179 other --filter exists, the new filter expression will be combined
180 with them by &&.
181 -a, --all-cpus
183 System-wide collection from all CPUs (default if no target is
184 specified).
185 -p, --pid=
187 Record events on existing process ID (comma separated list).
188 -t, --tid=
190 Record events on existing thread ID (comma separated list). This
191 option also disables inheritance by default. Enable it by adding
192 --inherit.
193 -u, --uid=
195 Record events in threads owned by uid. Name or number.
196 -r, --realtime=
198 Collect data with this RT SCHED_FIFO priority.
199 --no-buffering
201 Collect data without buffering.
202 -c, --count=
204 Event period to sample.
205 -o, --output=
207 Output file name.
208 -i, --no-inherit
210 Child tasks do not inherit counters.
211 -F, --freq=
213 Profile at this frequency. Use max to use the currently maximum
214 allowed frequency, i.e. the value in the
215 kernel.perf_event_max_sample_rate sysctl. Will throttle down to the
216 currently maximum allowed frequency. See --strict-freq.
217 --strict-freq
219 Fail if the specified frequency can’t be used.
220 -m, --mmap-pages=
222 Number of mmap data pages (must be a power of two) or size
223 specification with appended unit character - B/K/M/G. The size is
224 rounded up to have nearest pages power of two value. Also, by
225 adding a comma, the number of mmap pages for AUX area tracing can
226 be specified.
227 --group
229 Put all events in a single event group. This precedes the --event
230 option and remains only for backward compatibility. See --event.
231 -g
233 Enables call-graph (stack chain/backtrace) recording for both
234 kernel space and user space.
235 --call-graph
237 Setup and enable call-graph (stack chain/backtrace) recording,
238 implies -g. Default is "fp" (for user space).
239 The unwinding method used for kernel space is dependent on the
241 unwinder used by the active kernel configuration, i.e
242 CONFIG_UNWINDER_FRAME_POINTER (fp) or CONFIG_UNWINDER_ORC (orc)
243 Any option specified here controls the method used for user space.
245 Valid options are "fp" (frame pointer), "dwarf" (DWARF's CFI -
247 Call Frame Information) or "lbr" (Hardware Last Branch Record
248 facility).
249 In some systems, where binaries are build with gcc
251 --fomit-frame-pointer, using the "fp" method will produce bogus
252 call graphs, using "dwarf", if available (perf tools linked to
253 the libunwind or libdw library) should be used instead.
254 Using the "lbr" method doesn't require any compiler options. It
255 will produce call graphs from the hardware LBR registers. The
256 main limitation is that it is only available on new Intel
257 platforms, such as Haswell. It can only get user call chain. It
258 doesn't work with branch stack sampling at the same time.
259 When "dwarf" recording is used, perf also records (user) stack dump
261 when sampled. Default size of the stack dump is 8192 (bytes).
262 User can change the size by passing the size after comma like
263 "--call-graph dwarf,4096".
264 When "fp" recording is used, perf tries to save stack enties
266 up to the number specified in sysctl.kernel.perf_event_max_stack
267 by default. User can change the number by passing it after comma
268 like "--call-graph fp,32".
269 -q, --quiet
271 Don’t print any warnings or messages, useful for scripting.
272 -v, --verbose
274 Be more verbose (show counter open errors, etc).
275 -s, --stat
277 Record per-thread event counts. Use it with perf report -T to see
278 the values.
279 -d, --data
281 Record the sample virtual addresses.
282 --phys-data
284 Record the sample physical addresses.
285 --data-page-size
287 Record the sampled data address data page size.
288 --code-page-size
290 Record the sampled code address (ip) page size
291 -T, --timestamp
293 Record the sample timestamps. Use it with perf report -D to see the
294 timestamps, for instance.
295 -P, --period
297 Record the sample period.
298 --sample-cpu
300 Record the sample cpu.
301 --sample-identifier
303 Record the sample identifier i.e. PERF_SAMPLE_IDENTIFIER bit set in
304 the sample_type member of the struct perf_event_attr argument to
305 the perf_event_open system call.
306 -n, --no-samples
308 Don’t sample.
309 -R, --raw-samples
311 Collect raw sample records from all opened counters (default for
312 tracepoint counters).
313 -C, --cpu
315 Collect samples only on the list of CPUs provided. Multiple CPUs
316 can be provided as a comma-separated list with no space: 0,1.
317 Ranges of CPUs are specified with -: 0-2. In per-thread mode with
318 inheritance mode on (default), samples are captured only when the
319 thread executes on the designated CPUs. Default is to monitor all
320 CPUs.
321 -B, --no-buildid
323 Do not save the build ids of binaries in the perf.data files. This
324 skips post processing after recording, which sometimes makes the
325 final step in the recording process to take a long time, as it
326 needs to process all events looking for mmap records. The downside
327 is that it can misresolve symbols if the workload binaries used
328 when recording get locally rebuilt or upgraded, because the only
329 key available in this case is the pathname. You can also set the
330 "record.build-id" config variable to 'skip to have this behaviour
331 permanently.
332 -N, --no-buildid-cache
334 Do not update the buildid cache. This saves some overhead in
335 situations where the information in the perf.data file (which
336 includes buildids) is sufficient. You can also set the
337 "record.build-id" config variable to no-cache to have the same
338 effect.
339 -G name,..., --cgroup name,...
341 monitor only in the container (cgroup) called "name". This option
342 is available only in per-cpu mode. The cgroup filesystem must be
343 mounted. All threads belonging to container "name" are monitored
344 when they run on the monitored CPUs. Multiple cgroups can be
345 provided. Each cgroup is applied to the corresponding event, i.e.,
346 first cgroup to first event, second cgroup to second event and so
347 on. It is possible to provide an empty cgroup (monitor all the
348 time) using, e.g., -G foo,,bar. Cgroups must have corresponding
349 events, i.e., they always refer to events defined earlier on the
350 command line. If the user wants to track multiple events for a
351 specific cgroup, the user can use -e e1 -e e2 -G foo,foo or just
352 use -e e1 -e e2 -G foo.
353 If wanting to monitor, say, cycles for a cgroup and also for system
355 wide, this command line can be used: perf stat -e cycles -G cgroup_name
356 -a -e cycles.
357 -b, --branch-any
359 Enable taken branch stack sampling. Any type of taken branch may be
360 sampled. This is a shortcut for --branch-filter any. See
361 --branch-filter for more infos.
362 -j, --branch-filter
364 Enable taken branch stack sampling. Each sample captures a series
365 of consecutive taken branches. The number of branches captured with
366 each sample depends on the underlying hardware, the type of
367 branches of interest, and the executed code. It is possible to
368 select the types of branches captured by enabling filters. The
369 following filters are defined:
370 • any: any type of branches
372 • any_call: any function call or system call
374 • any_ret: any function return or system call return
376 • ind_call: any indirect branch
378 • call: direct calls, including far (to/from kernel) calls
380 • u: only when the branch target is at the user level
382 • k: only when the branch target is in the kernel
384 • hv: only when the target is at the hypervisor level
386 • in_tx: only when the target is in a hardware transaction
388 • no_tx: only when the target is not in a hardware transaction
390 • abort_tx: only when the target is a hardware transaction abort
392 • cond: conditional branches
394 • save_type: save branch type during sampling in case binary is
396 not available later For the platforms with Intel Arch LBR
397 support (12th-Gen+ client or 4th-Gen Xeon+ server), the save
398 branch type is unconditionally enabled when the taken branch
399 stack sampling is enabled.
400 • priv: save privilege state during sampling in case binary is
402 not available later
403 The option requires at least one branch type among any, any_call,
405 any_ret, ind_call, cond. The privilege levels may be omitted, in
406 which case, the privilege levels of the associated event are
407 applied to the branch filter. Both kernel (k) and hypervisor (hv)
408 privilege levels are subject to permissions. When sampling on
409 multiple events, branch stack sampling is enabled for all the
410 sampling events. The sampled branch type is the same for all
411 events. The various filters must be specified as a comma separated
412 list: --branch-filter any_ret,u,k Note that this feature may not be
413 available on all processors.
414 -W, --weight
416 Enable weightened sampling. An additional weight is recorded per
417 sample and can be displayed with the weight and local_weight sort
418 keys. This currently works for TSX abort events and some memory
419 events in precise mode on modern Intel CPUs.
420 --namespaces
422 Record events of type PERF_RECORD_NAMESPACES. This enables
423 cgroup_id sort key.
424 --all-cgroups
426 Record events of type PERF_RECORD_CGROUP. This enables cgroup sort
427 key.
428 --transaction
430 Record transaction flags for transaction related events.
431 --per-thread
433 Use per-thread mmaps. By default per-cpu mmaps are created. This
434 option overrides that and uses per-thread mmaps. A side-effect of
435 that is that inheritance is automatically disabled. --per-thread is
436 ignored with a warning if combined with -a or -C options.
437 -D, --delay=
439 After starting the program, wait msecs before measuring (-1: start
440 with events disabled), or enable events only for specified ranges
441 of msecs (e.g. -D 10-20,30-40 means wait 10 msecs, enable for 10
442 msecs, wait 10 msecs, enable for 10 msecs, then stop). Note,
443 delaying enabling of events is useful to filter out the startup
444 phase of the program, which is often very different.
445 -I, --intr-regs
447 Capture machine state (registers) at interrupt, i.e., on counter
448 overflows for each sample. List of captured registers depends on
449 the architecture. This option is off by default. It is possible to
450 select the registers to sample using their symbolic names, e.g. on
451 x86, ax, si. To list the available registers use --intr-regs=\?. To
452 name registers, pass a comma separated list such as
453 --intr-regs=ax,bx. The list of register is architecture dependent.
454 --user-regs
456 Similar to -I, but capture user registers at sample time. To list
457 the available user registers use --user-regs=\?.
458 --running-time
460 Record running and enabled time for read events (:S)
461 -k, --clockid
463 Sets the clock id to use for the various time fields in the
464 perf_event_type records. See clock_gettime(). In particular
465 CLOCK_MONOTONIC and CLOCK_MONOTONIC_RAW are supported, some events
466 might also allow CLOCK_BOOTTIME, CLOCK_REALTIME and CLOCK_TAI.
467 -S, --snapshot
469 Select AUX area tracing Snapshot Mode. This option is valid only
470 with an AUX area tracing event. Optionally, certain snapshot
471 capturing parameters can be specified in a string that follows this
472 option: e: take one last snapshot on exit; guarantees that there is
473 at least one snapshot in the output file; <size>: if the PMU
474 supports this, specify the desired snapshot size.
475 In Snapshot Mode trace data is captured only when signal SIGUSR2 is
477 received and on exit if the above e option is given.
478 --aux-sample[=OPTIONS]
480 Select AUX area sampling. At least one of the events selected by
481 the -e option must be an AUX area event. Samples on other events
482 will be created containing data from the AUX area. Optionally
483 sample size may be specified, otherwise it defaults to 4KiB.
484 --proc-map-timeout
486 When processing pre-existing threads /proc/XXX/mmap, it may take a
487 long time, because the file may be huge. A time out is needed in
488 such cases. This option sets the time out limit. The default value
489 is 500 ms.
490 --switch-events
492 Record context switch events i.e. events of type PERF_RECORD_SWITCH
493 or PERF_RECORD_SWITCH_CPU_WIDE. In some cases (e.g. Intel PT,
494 CoreSight or Arm SPE) switch events will be enabled automatically,
495 which can be suppressed by by the option --no-switch-events.
496 --clang-path=PATH
498 Path to clang binary to use for compiling BPF scriptlets. (enabled
499 when BPF support is on)
500 --clang-opt=OPTIONS
502 Options passed to clang when compiling BPF scriptlets. (enabled
503 when BPF support is on)
504 --vmlinux=PATH
506 Specify vmlinux path which has debuginfo. (enabled when BPF
507 prologue is on)
508 --buildid-all
510 Record build-id of all DSOs regardless whether it’s actually hit or
511 not.
512 --buildid-mmap
514 Record build ids in mmap2 events, disables build id cache (implies
515 --no-buildid).
516 --aio[=n]
518 Use <n> control blocks in asynchronous (Posix AIO) trace writing
519 mode (default: 1, max: 4). Asynchronous mode is supported only when
520 linking Perf tool with libc library providing implementation for
521 Posix AIO API.
522 --affinity=mode
524 Set affinity mask of trace reading thread according to the policy
525 defined by mode value: node - thread affinity mask is set to NUMA
526 node cpu mask of the processed mmap buffer cpu - thread affinity
527 mask is set to cpu of the processed mmap buffer
528 --mmap-flush=number
530 Specify minimal number of bytes that is extracted from mmap data
531 pages and processed for output. One can specify the number using
532 B/K/M/G suffixes.
533 The maximal allowed value is a quarter of the size of mmaped data
535 pages.
536 The default option value is 1 byte which means that every time that the
538 output writing thread finds some new data in the mmaped buffer the data
539 is extracted, possibly compressed (-z) and written to the output,
540 perf.data or pipe.
541 Larger data chunks are compressed more effectively in comparison to
543 smaller chunks so extraction of larger chunks from the mmap data pages
544 is preferable from the perspective of output size reduction.
545 Also at some cases executing less output write syscalls with bigger
547 data size can take less time than executing more output write syscalls
548 with smaller data size thus lowering runtime profiling overhead.
549 -z, --compression-level[=n]
551 Produce compressed trace using specified level n (default: 1 -
552 fastest compression, 22 - smallest trace)
553 --all-kernel
555 Configure all used events to run in kernel space.
556 --all-user
558 Configure all used events to run in user space.
559 --kernel-callchains
561 Collect callchains only from kernel space. I.e. this option sets
562 perf_event_attr.exclude_callchain_user to 1.
563 --user-callchains
565 Collect callchains only from user space. I.e. this option sets
566 perf_event_attr.exclude_callchain_kernel to 1.
567 Don’t use both --kernel-callchains and --user-callchains at the same
569 time or no callchains will be collected.
570 --timestamp-filename Append timestamp to output file name.
572 --timestamp-boundary
574 Record timestamp boundary (time of first/last samples).
575 --switch-output[=mode]
577 Generate multiple perf.data files, timestamp prefixed, switching to
578 a new one based on mode value: "signal" - when receiving a SIGUSR2
579 (default value) or <size> - when reaching the size threshold, size
580 is expected to be a number with appended unit character - B/K/M/G
581 <time> - when reaching the time threshold, size is expected to be a
582 number with appended unit character - s/m/h/d
583 Note: the precision of the size threshold hugely depends
585 on your configuration - the number and size of your ring
586 buffers (-m). It is generally more precise for higher sizes
587 (like >5M), for lower values expect different sizes.
588 A possible use case is to, given an external event, slice the perf.data
590 file that gets then processed, possibly via a perf script, to decide if
591 that particular perf.data snapshot should be kept or not.
592 Implies --timestamp-filename, --no-buildid and --no-buildid-cache. The
594 reason for the latter two is to reduce the data file switching
595 overhead. You can still switch them on with:
596 --switch-output --no-no-buildid --no-no-buildid-cache
598 --switch-output-event
600 Events that will cause the switch of the perf.data file,
601 auto-selecting --switch-output=signal, the results are similar as
602 internally the side band thread will also send a SIGUSR2 to the
603 main one.
604 Uses the same syntax as --event, it will just not be recorded, serving
606 only to switch the perf.data file as soon as the --switch-output event
607 is processed by a separate sideband thread.
608 This sideband thread is also used to other purposes, like processing
610 the PERF_RECORD_BPF_EVENT records as they happen, asking the kernel for
611 extra BPF information, etc.
612 --switch-max-files=N
614 When rotating perf.data with --switch-output, only keep N files.
615 --dry-run
617 Parse options then exit. --dry-run can be used to detect errors in
618 cmdline options.
619 perf record --dry-run -e can act as a BPF script compiler if
621 llvm.dump-obj in config file is set to true.
622 --synth=TYPE
624 Collect and synthesize given type of events (comma separated). Note
625 that this option controls the synthesis from the /proc filesystem
626 which represent task status for pre-existing threads.
627 Kernel (and some other) events are recorded regardless of the choice in
629 this option. For example, --synth=no would have MMAP events for kernel
630 and modules.
631 Available types are: task - synthesize FORK and COMM events for each
633 task mmap - synthesize MMAP events for each process (implies task)
634 cgroup - synthesize CGROUP events for each cgroup all - synthesize all
635 events (default) no - do not synthesize any of the above events
636 --tail-synthesize
638 Instead of collecting non-sample events (for example, fork, comm,
639 mmap) at the beginning of record, collect them during finalizing an
640 output file. The collected non-sample events reflects the status of
641 the system when record is finished.
642 --overwrite
644 Makes all events use an overwritable ring buffer. An overwritable
645 ring buffer works like a flight recorder: when it gets full, the
646 kernel will overwrite the oldest records, that thus will never make
647 it to the perf.data file.
648 When --overwrite and --switch-output are used perf records and drops
650 events until it receives a signal, meaning that something unusual was
651 detected that warrants taking a snapshot of the most current events,
652 those fitting in the ring buffer at that moment.
653 overwrite attribute can also be set or canceled for an event using
655 config terms. For example: cycles/overwrite/ and
656 instructions/no-overwrite/.
657 Implies --tail-synthesize.
659 --kcore
661 Make a copy of /proc/kcore and place it into a directory with the
662 perf data file.
663 --max-size=<size>
665 Limit the sample data max size, <size> is expected to be a number
666 with appended unit character - B/K/M/G
667 --num-thread-synthesize
669 The number of threads to run when synthesizing events for existing
670 processes. By default, the number of threads equals 1.
671 --control=fifo:ctl-fifo[,ack-fifo], --control=fd:ctl-fd[,ack-fd]
673 ctl-fifo / ack-fifo are opened and used as ctl-fd / ack-fd as
674 follows. Listen on ctl-fd descriptor for command to control
675 measurement.
676 Available commands: enable : enable events disable : disable events
678 enable name : enable event name disable name : disable event name
679 snapshot : AUX area tracing snapshot). stop : stop perf record ping :
680 ping
681 'evlist [-v|-g|-F] : display all events
683 -F Show just the sample frequency used for each event.
684 -v Show all fields.
685 -g Show event group information.
686 Measurements can be started with events disabled using --delay=-1
688 option. Optionally send control command completion (ack\n) to ack-fd
689 descriptor to synchronize with the controlling process. Example of bash
690 shell script to enable and disable events during measurements:
691 #!/bin/bash
693 ctl_dir=/tmp/
695 ctl_fifo=${ctl_dir}perf_ctl.fifo
697 test -p ${ctl_fifo} && unlink ${ctl_fifo}
698 mkfifo ${ctl_fifo}
699 exec {ctl_fd}<>${ctl_fifo}
700 ctl_ack_fifo=${ctl_dir}perf_ctl_ack.fifo
702 test -p ${ctl_ack_fifo} && unlink ${ctl_ack_fifo}
703 mkfifo ${ctl_ack_fifo}
704 exec {ctl_fd_ack}<>${ctl_ack_fifo}
705 perf record -D -1 -e cpu-cycles -a \
707 --control fd:${ctl_fd},${ctl_fd_ack} \
708 -- sleep 30 &
709 perf_pid=$!
710 sleep 5 && echo 'enable' >&${ctl_fd} && read -u ${ctl_fd_ack} e1 && echo "enabled(${e1})"
712 sleep 10 && echo 'disable' >&${ctl_fd} && read -u ${ctl_fd_ack} d1 && echo "disabled(${d1})"
713 exec {ctl_fd_ack}>&-
715 unlink ${ctl_ack_fifo}
716 exec {ctl_fd}>&-
718 unlink ${ctl_fifo}
719 wait -n ${perf_pid}
721 exit $?
722 --threads=<spec>
724 Write collected trace data into several data files using parallel
725 threads. <spec> value can be user defined list of masks. Masks
726 separated by colon define CPUs to be monitored by a thread and
727 affinity mask of that thread is separated by slash:
728 <cpus mask 1>/<affinity mask 1>:<cpus mask 2>/<affinity mask 2>:...
730 CPUs or affinity masks must not overlap with other corresponding masks.
732 Invalid CPUs are ignored, but masks containing only invalid CPUs are
733 not allowed.
734 For example user specification like the following:
736 0,2-4/2-4:1,5-7/5-7
738 specifies parallel threads layout that consists of two threads, the
740 first thread monitors CPUs 0 and 2-4 with the affinity mask 2-4, the
741 second monitors CPUs 1 and 5-7 with the affinity mask 5-7.
742 <spec> value can also be a string meaning predefined parallel threads
744 layout:
745 cpu - create new data streaming thread for every monitored cpu
747 core - create new thread to monitor CPUs grouped by a core
748 package - create new thread to monitor CPUs grouped by a package
749 numa - create new threed to monitor CPUs grouped by a NUMA domain
750 Predefined layouts can be used on systems with large number of CPUs in
752 order not to spawn multiple per-cpu streaming threads but still avoid
753 LOST events in data directory files. Option specified with no or empty
754 value defaults to CPU layout. Masks defined or provided by the option
755 value are filtered through the mask provided by -C option.
756 --debuginfod[=URLs]
758 Specify debuginfod URL to be used when cacheing perf.data binaries,
759 it follows the same syntax as the DEBUGINFOD_URLS variable, like:
760 http://192.168.122.174:8002
762 If the URLs is not specified, the value of DEBUGINFOD_URLS
764 system environment variable is used.
765 --off-cpu
767 Enable off-cpu profiling with BPF. The BPF program will collect
768 task scheduling information with (user) stacktrace and save them as
769 sample data of a software event named "offcpu-time". The sample
770 period will have the time the task slept in nanoseconds.
771 Note that BPF can collect stack traces using frame pointer ("fp")
773 only, as of now. So the applications built without the frame
774 pointer might see bogus addresses.
775
777 Support for Intel hybrid events within perf tools.
778 For some Intel platforms, such as AlderLake, which is hybrid platform
780 and it consists of atom cpu and core cpu. Each cpu has dedicated event
781 list. Part of events are available on core cpu, part of events are
782 available on atom cpu and even part of events are available on both.
783 Kernel exports two new cpu pmus via sysfs: /sys/devices/cpu_core
785 /sys/devices/cpu_atom
786 The cpus files are created under the directories. For example,
788 cat /sys/devices/cpu_core/cpus 0-15
790 cat /sys/devices/cpu_atom/cpus 16-23
792 It indicates cpu0-cpu15 are core cpus and cpu16-cpu23 are atom cpus.
794 As before, use perf-list to list the symbolic event.
796 perf list
798 inst_retired.any [Fixed Counter: Counts the number of instructions
800 retired. Unit: cpu_atom] inst_retired.any [Number of instructions
801 retired. Fixed Counter - architectural event. Unit: cpu_core]
802 The Unit: xxx is added to brief description to indicate which pmu the
804 event is belong to. Same event name but with different pmu can be
805 supported.
806 Enable hybrid event with a specific pmu
808 To enable a core only event or atom only event, following syntax is
810 supported:
811 cpu_core/<event name>/
813 or
814 cpu_atom/<event name>/
815 For example, count the cycles event on core cpus.
817 perf stat -e cpu_core/cycles/
819 Create two events for one hardware event automatically
821 When creating one event and the event is available on both atom and
823 core, two events are created automatically. One is for atom, the other
824 is for core. Most of hardware events and cache events are available on
825 both cpu_core and cpu_atom.
826 For hardware events, they have pre-defined configs (e.g. 0 for cycles).
828 But on hybrid platform, kernel needs to know where the event comes from
829 (from atom or from core). The original perf event type
830 PERF_TYPE_HARDWARE can’t carry pmu information. So now this type is
831 extended to be PMU aware type. The PMU type ID is stored at
832 attr.config[63:32].
833 PMU type ID is retrieved from sysfs. /sys/devices/cpu_atom/type
835 /sys/devices/cpu_core/type
836 The new attr.config layout for PERF_TYPE_HARDWARE:
838 PERF_TYPE_HARDWARE: 0xEEEEEEEE000000AA AA: hardware event ID EEEEEEEE:
840 PMU type ID
841 Cache event is similar. The type PERF_TYPE_HW_CACHE is extended to be
843 PMU aware type. The PMU type ID is stored at attr.config[63:32].
844 The new attr.config layout for PERF_TYPE_HW_CACHE:
846 PERF_TYPE_HW_CACHE: 0xEEEEEEEE00DDCCBB BB: hardware cache ID CC:
848 hardware cache op ID DD: hardware cache op result ID EEEEEEEE: PMU type
849 ID
850 When enabling a hardware event without specified pmu, such as, perf
852 stat -e cycles -a (use system-wide in this example), two events are
853 created automatically.
854 ------------------------------------------------------------
856 perf_event_attr:
857 size 120
858 config 0x400000000
859 sample_type IDENTIFIER
860 read_format TOTAL_TIME_ENABLED|TOTAL_TIME_RUNNING
861 disabled 1
862 inherit 1
863 exclude_guest 1
864 ------------------------------------------------------------
865 and
867 ------------------------------------------------------------
869 perf_event_attr:
870 size 120
871 config 0x800000000
872 sample_type IDENTIFIER
873 read_format TOTAL_TIME_ENABLED|TOTAL_TIME_RUNNING
874 disabled 1
875 inherit 1
876 exclude_guest 1
877 ------------------------------------------------------------
878 type 0 is PERF_TYPE_HARDWARE. 0x4 in 0x400000000 indicates it’s
880 cpu_core pmu. 0x8 in 0x800000000 indicates it’s cpu_atom pmu (atom pmu
881 type id is random).
882 The kernel creates cycles (0x400000000) on cpu0-cpu15 (core cpus), and
884 create cycles (0x800000000) on cpu16-cpu23 (atom cpus).
885 For perf-stat result, it displays two events:
887 Performance counter stats for 'system wide':
889 6,744,979 cpu_core/cycles/
891 1,965,552 cpu_atom/cycles/
892 The first cycles is core event, the second cycles is atom event.
894 Thread mode example:
896 perf-stat reports the scaled counts for hybrid event and with a
898 percentage displayed. The percentage is the event’s running
899 time/enabling time.
900 One example, triad_loop runs on cpu16 (atom core), while we can see the
902 scaled value for core cycles is 160,444,092 and the percentage is
903 0.47%.
904 perf stat -e cycles -- taskset -c 16 ./triad_loop
906 As previous, two events are created.
908 .ft C
911 perf_event_attr:
912 size 120
913 config 0x400000000
914 sample_type IDENTIFIER
915 read_format TOTAL_TIME_ENABLED|TOTAL_TIME_RUNNING
916 disabled 1
917 inherit 1
918 enable_on_exec 1
919 exclude_guest 1
920 .ft
921 and
924 .ft C
927 perf_event_attr:
928 size 120
929 config 0x800000000
930 sample_type IDENTIFIER
931 read_format TOTAL_TIME_ENABLED|TOTAL_TIME_RUNNING
932 disabled 1
933 inherit 1
934 enable_on_exec 1
935 exclude_guest 1
936 .ft
937 Performance counter stats for 'taskset -c 16 ./triad_loop':
940 233,066,666 cpu_core/cycles/ (0.43%)
942 604,097,080 cpu_atom/cycles/ (99.57%)
943 perf-record:
945 If there is no -e specified in perf record, on hybrid platform, it
947 creates two default cycles and adds them to event list. One is for
948 core, the other is for atom.
949 perf-stat:
951 If there is no -e specified in perf stat, on hybrid platform, besides
953 of software events, following events are created and added to event
954 list in order.
955 cpu_core/cycles/, cpu_atom/cycles/, cpu_core/instructions/,
957 cpu_atom/instructions/, cpu_core/branches/, cpu_atom/branches/,
958 cpu_core/branch-misses/, cpu_atom/branch-misses/
959 Of course, both perf-stat and perf-record support to enable hybrid
961 event with a specific pmu.
962 e.g. perf stat -e cpu_core/cycles/ perf stat -e cpu_atom/cycles/ perf
964 stat -e cpu_core/r1a/ perf stat -e cpu_atom/L1-icache-loads/ perf stat
965 -e cpu_core/cycles/,cpu_atom/instructions/ perf stat -e
966 {cpu_core/cycles/,cpu_core/instructions/}
967 But {cpu_core/cycles/,cpu_atom/instructions/} will return warning and
969 disable grouping, because the pmus in group are not matched (cpu_core
970 vs. cpu_atom).
971
973 perf-stat(1), perf-list(1), perf-intel-pt(1)
974perf 01/12/2023 PERF-RECORD(1)