6 perf-record - Run a command and record its profile into perf.data
11 'perf record' [-e <EVENT> | --event=EVENT] [-a] <command>
12 'perf record' [-e <EVENT> | --event=EVENT] [-a] -- <command> [<options>]
16 This command runs a command and gathers a performance counter profile
17 from it, into perf.data - without displaying anything.
19 This file can then be inspected later on, using 'perf report'.
25 Any command you can specify in a shell.
29 Select the PMU event. Selection can be:
31 - a symbolic event name (use 'perf list' to list all events)
33 - a raw PMU event (eventsel+umask) in the form of rNNN where NNN is a
34 hexadecimal event descriptor.
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.
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/*.
44 - a symbolically formed event like 'pmu/config=M,config1=N,config3=K/'
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/*
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.
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.
73 See the linkperf:perf-list[1] man page for more parameters.
75 Note: If user explicitly sets options which conflict with the params,
76 the value set by the parameters will be overridden.
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:
83 perf record -e some_event/@cfg1,@cfg2=config/ ...
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.
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
97 If you want to profile write accesses in [0x1000~1008), just set
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
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.:
109 perf record --clang-opt "-DLINUX_VERSION_CODE=0x50000" \
110 -e tests/bpf-script-example.c
112 Note: '--clang-opt' must be placed before '--event/-e'.
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.
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).
126 In the case of tracepoints, multiple '--filter' options are combined
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.
135 Address filters have the format:
137 filter|start|stop|tracestop <start> [/ <size>] [@<file name>]
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.
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>.
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.
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
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
165 If symbol names (or '*') are provided, they must be surrounded by white
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.
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.
175 Multiple filters can be separated with space or comma.
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
186 System-wide collection from all CPUs (default if no target is specified).
190 Record events on existing process ID (comma separated list).
194 Record events on existing thread ID (comma separated list).
195 This option also disables inheritance by default. Enable it by adding
200 Record events in threads owned by uid. Name or number.
204 Collect data with this RT SCHED_FIFO priority.
207 Collect data without buffering.
211 Event period to sample.
219 Child tasks do not inherit counters.
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.
229 Fail if the specified frequency can't be used.
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.
240 Put all events in a single event group. This precedes the --event
241 option and remains only for backward compatibility. See --event.
244 Enables call-graph (stack chain/backtrace) recording for both
245 kernel space and user space.
248 Setup and enable call-graph (stack chain/backtrace) recording,
249 implies -g. Default is "fp" (for user space).
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)
255 Any option specified here controls the method used for user space.
257 Valid options are "fp" (frame pointer), "dwarf" (DWARF's CFI -
258 Call Frame Information) or "lbr" (Hardware Last Branch Record
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.
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".
278 Don't print any message, useful for scripting.
282 Be more verbose (show counter open errors, etc).
286 Record per-thread event counts. Use it with 'perf report -T' to see
291 Record the sample virtual addresses.
294 Record the sample physical addresses.
298 Record the sample timestamps. Use it with 'perf report -D' to see the
299 timestamps, for instance.
303 Record the sample period.
306 Record the sample cpu.
314 Collect raw sample records from all opened counters (default for tracepoint counters).
318 Collect samples only on the list of CPUs provided. Multiple CPUs can be provided as a
319 comma-separated list with no space: 0,1. Ranges of CPUs are specified with -: 0-2.
320 In per-thread mode with inheritance mode on (default), samples are captured only when
321 the thread executes on the designated CPUs. Default is to monitor all CPUs.
325 Do not save the build ids of binaries in the perf.data files. This skips
326 post processing after recording, which sometimes makes the final step in
327 the recording process to take a long time, as it needs to process all
328 events looking for mmap records. The downside is that it can misresolve
329 symbols if the workload binaries used when recording get locally rebuilt
330 or upgraded, because the only key available in this case is the
331 pathname. You can also set the "record.build-id" config variable to
332 'skip to have this behaviour permanently.
336 Do not update the buildid cache. This saves some overhead in situations
337 where the information in the perf.data file (which includes buildids)
338 is sufficient. You can also set the "record.build-id" config variable to
339 'no-cache' to have the same effect.
343 monitor only in the container (cgroup) called "name". This option is available only
344 in per-cpu mode. The cgroup filesystem must be mounted. All threads belonging to
345 container "name" are monitored when they run on the monitored CPUs. Multiple cgroups
346 can be provided. Each cgroup is applied to the corresponding event, i.e., first cgroup
347 to first event, second cgroup to second event and so on. It is possible to provide
348 an empty cgroup (monitor all the time) using, e.g., -G foo,,bar. Cgroups must have
349 corresponding events, i.e., they always refer to events defined earlier on the command
350 line. If the user wants to track multiple events for a specific cgroup, the user can
351 use '-e e1 -e e2 -G foo,foo' or just use '-e e1 -e e2 -G foo'.
353 If wanting to monitor, say, 'cycles' for a cgroup and also for system wide, this
354 command line can be used: 'perf stat -e cycles -G cgroup_name -a -e cycles'.
358 Enable taken branch stack sampling. Any type of taken branch may be sampled.
359 This is a shortcut for --branch-filter any. See --branch-filter for more infos.
363 Enable taken branch stack sampling. Each sample captures a series of consecutive
364 taken branches. The number of branches captured with each sample depends on the
365 underlying hardware, the type of branches of interest, and the executed code.
366 It is possible to select the types of branches captured by enabling filters. The
367 following filters are defined:
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
384 The option requires at least one branch type among any, any_call, any_ret, ind_call, cond.
385 The privilege levels may be omitted, in which case, the privilege levels of the associated
386 event are applied to the branch filter. Both kernel (k) and hypervisor (hv) privilege
387 levels are subject to permissions. When sampling on multiple events, branch stack sampling
388 is enabled for all the sampling events. The sampled branch type is the same for all events.
389 The various filters must be specified as a comma separated list: --branch-filter any_ret,u,k
390 Note that this feature may not be available on all processors.
393 Enable weightened sampling. An additional weight is recorded per sample and can be
394 displayed with the weight and local_weight sort keys. This currently works for TSX
395 abort events and some memory events in precise mode on modern Intel CPUs.
398 Record events of type PERF_RECORD_NAMESPACES. This enables 'cgroup_id' sort key.
401 Record events of type PERF_RECORD_CGROUP. This enables 'cgroup' sort key.
404 Record transaction flags for transaction related events.
407 Use per-thread mmaps. By default per-cpu mmaps are created. This option
408 overrides that and uses per-thread mmaps. A side-effect of that is that
409 inheritance is automatically disabled. --per-thread is ignored with a warning
410 if combined with -a or -C options.
414 After starting the program, wait msecs before measuring (-1: start with events
415 disabled). This is useful to filter out the startup phase of the program, which
416 is often very different.
420 Capture machine state (registers) at interrupt, i.e., on counter overflows for
421 each sample. List of captured registers depends on the architecture. This option
422 is off by default. It is possible to select the registers to sample using their
423 symbolic 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.
428 Similar to -I, but capture user registers at sample time. To list the available
429 user registers use --user-regs=\?.
432 Record running and enabled time for read events (:S)
436 Sets the clock id to use for the various time fields in the perf_event_type
437 records. See clock_gettime(). In particular CLOCK_MONOTONIC and
438 CLOCK_MONOTONIC_RAW are supported, some events might also allow
439 CLOCK_BOOTTIME, CLOCK_REALTIME and CLOCK_TAI.
443 Select AUX area tracing Snapshot Mode. This option is valid only with an
444 AUX area tracing event. Optionally, certain snapshot capturing parameters
445 can 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.
450 In Snapshot Mode trace data is captured only when signal SIGUSR2 is received
451 and on exit if the above 'e' option is given.
453 --aux-sample[=OPTIONS]::
454 Select AUX area sampling. At least one of the events selected by the -e option
455 must be an AUX area event. Samples on other events will be created containing
456 data from the AUX area. Optionally sample size may be specified, otherwise it
460 When processing pre-existing threads /proc/XXX/mmap, it may take a long time,
461 because the file may be huge. A time out is needed in such cases.
462 This option sets the time out limit. The default value is 500 ms.
465 Record context switch events i.e. events of type PERF_RECORD_SWITCH or
466 PERF_RECORD_SWITCH_CPU_WIDE. In some cases (e.g. Intel PT or CoreSight)
467 switch events will be enabled automatically, which can be suppressed by
468 by the option --no-switch-events.
471 Path to clang binary to use for compiling BPF scriptlets.
472 (enabled when BPF support is on)
474 --clang-opt=OPTIONS::
475 Options passed to clang when compiling BPF scriptlets.
476 (enabled when BPF support is on)
479 Specify vmlinux path which has debuginfo.
480 (enabled when BPF prologue is on)
483 Record build-id of all DSOs regardless whether it's actually hit or not.
486 Use <n> control blocks in asynchronous (Posix AIO) trace writing mode (default: 1, max: 4).
487 Asynchronous mode is supported only when linking Perf tool with libc library
488 providing implementation for Posix AIO API.
491 Set 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
495 --mmap-flush=number::
497 Specify minimal number of bytes that is extracted from mmap data pages and
498 processed for output. One can specify the number using B/K/M/G suffixes.
500 The maximal allowed value is a quarter of the size of mmaped data pages.
502 The default option value is 1 byte which means that every time that the output
503 writing thread finds some new data in the mmaped buffer the data is extracted,
504 possibly compressed (-z) and written to the output, perf.data or pipe.
506 Larger data chunks are compressed more effectively in comparison to smaller
507 chunks so extraction of larger chunks from the mmap data pages is preferable
508 from the perspective of output size reduction.
510 Also at some cases executing less output write syscalls with bigger data size
511 can take less time than executing more output write syscalls with smaller data
512 size thus lowering runtime profiling overhead.
515 --compression-level[=n]::
516 Produce compressed trace using specified level n (default: 1 - fastest compression,
520 Configure all used events to run in kernel space.
523 Configure all used events to run in user space.
525 --kernel-callchains::
526 Collect callchains only from kernel space. I.e. this option sets
527 perf_event_attr.exclude_callchain_user to 1.
530 Collect callchains only from user space. I.e. this option sets
531 perf_event_attr.exclude_callchain_kernel to 1.
533 Don't use both --kernel-callchains and --user-callchains at the same time or no
534 callchains will be collected.
537 Append timestamp to output file name.
539 --timestamp-boundary::
540 Record timestamp boundary (time of first/last samples).
542 --switch-output[=mode]::
543 Generate multiple perf.data files, timestamp prefixed, switching to a new one
544 based 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
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.
556 A possible use case is to, given an external event, slice the perf.data file
557 that gets then processed, possibly via a perf script, to decide if that
558 particular perf.data snapshot should be kept or not.
560 Implies --timestamp-filename, --no-buildid and --no-buildid-cache.
561 The reason for the latter two is to reduce the data file switching
562 overhead. You can still switch them on with:
564 --switch-output --no-no-buildid --no-no-buildid-cache
566 --switch-output-event::
567 Events 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
569 thread will also send a SIGUSR2 to the main one.
571 Uses the same syntax as --event, it will just not be recorded, serving only to
572 switch the perf.data file as soon as the --switch-output event is processed by
573 a separate sideband thread.
575 This sideband thread is also used to other purposes, like processing the
576 PERF_RECORD_BPF_EVENT records as they happen, asking the kernel for extra BPF
579 --switch-max-files=N::
581 When rotating perf.data with --switch-output, only keep N files.
584 Parse options then exit. --dry-run can be used to detect errors in cmdline
587 'perf record --dry-run -e' can act as a BPF script compiler if llvm.dump-obj
588 in config file is set to true.
591 Instead of collecting non-sample events (for example, fork, comm, mmap) at
592 the beginning of record, collect them during finalizing an output file.
593 The collected non-sample events reflects the status of the system when
597 Makes all events use an overwritable ring buffer. An overwritable ring
598 buffer works like a flight recorder: when it gets full, the kernel will
599 overwrite the oldest records, that thus will never make it to the
602 When '--overwrite' and '--switch-output' are used perf records and drops
603 events until it receives a signal, meaning that something unusual was
604 detected that warrants taking a snapshot of the most current events,
605 those fitting in the ring buffer at that moment.
607 'overwrite' attribute can also be set or canceled for an event using
608 config terms. For example: 'cycles/overwrite/' and 'instructions/no-overwrite/'.
610 Implies --tail-synthesize.
613 Make a copy of /proc/kcore and place it into a directory with the perf data file.
616 Limit the sample data max size, <size> is expected to be a number with
617 appended unit character - B/K/M/G
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.
624 --pfm-events events::
625 Select a PMU event using libpfm4 syntax (see http://perfmon2.sf.net)
626 including support for event filters. For example '--pfm-events
627 inst_retired:any_p:u:c=1:i'. More than one event can be passed to the
628 option using the comma separator. Hardware events and generic hardware
629 events cannot be mixed together. The latter must be used with the -e
630 option. The -e option and this one can be mixed and matched. Events
631 can be grouped using the {} notation.
634 --control fd:ctl-fd[,ack-fd]
635 Listen 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
638 to synchronize with the controlling process. Example of bash shell script to enable and
639 disable events during measurements:
645 ctl_fifo=${ctl_dir}perf_ctl.fifo
646 test -p ${ctl_fifo} && unlink ${ctl_fifo}
648 exec {ctl_fd}<>${ctl_fifo}
650 ctl_ack_fifo=${ctl_dir}perf_ctl_ack.fifo
651 test -p ${ctl_ack_fifo} && unlink ${ctl_ack_fifo}
652 mkfifo ${ctl_ack_fifo}
653 exec {ctl_fd_ack}<>${ctl_ack_fifo}
655 perf record -D -1 -e cpu-cycles -a \
656 --control fd:${ctl_fd},${ctl_fd_ack} \
660 sleep 5 && echo 'enable' >&${ctl_fd} && read -u ${ctl_fd_ack} e1 && echo "enabled(${e1})"
661 sleep 10 && echo 'disable' >&${ctl_fd} && read -u ${ctl_fd_ack} d1 && echo "disabled(${d1})"
664 unlink ${ctl_ack_fifo}
675 linkperf:perf-stat[1], linkperf:perf-list[1], linkperf:perf-intel-pt[1]
projects / linux-2.6-microblaze.git / blob