Loading...
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] [-l] [-a] <command>
12'perf record' [-e <EVENT> | --event=EVENT] [-l] [-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_sources/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_sources/devices/<pmu>/format/*
45 param1 and param2 are defined as formats for the PMU in:
46 /sys/bus/event_sources/devices/<pmu>/format/*
47
48 There are also some params which are not defined in .../<pmu>/format/*.
49 These params can be used to overload default config values per event.
50 Here is a list of the params.
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 Note: If user explicitly sets options which conflict with the params,
61 the value set by the params will be overridden.
62
63 - a hardware breakpoint event in the form of '\mem:addr[/len][:access]'
64 where addr is the address in memory you want to break in.
65 Access is the memory access type (read, write, execute) it can
66 be passed as follows: '\mem:addr[:[r][w][x]]'. len is the range,
67 number of bytes from specified addr, which the breakpoint will cover.
68 If you want to profile read-write accesses in 0x1000, just set
69 'mem:0x1000:rw'.
70 If you want to profile write accesses in [0x1000~1008), just set
71 'mem:0x1000/8:w'.
72
73 - a group of events surrounded by a pair of brace ("{event1,event2,...}").
74 Each event is separated by commas and the group should be quoted to
75 prevent the shell interpretation. You also need to use --group on
76 "perf report" to view group events together.
77
78--filter=<filter>::
79 Event filter. This option should follow a event selector (-e) which
80 selects tracepoint event(s). Multiple '--filter' options are combined
81 using '&&'.
82
83--exclude-perf::
84 Don't record events issued by perf itself. This option should follow
85 a event selector (-e) which selects tracepoint event(s). It adds a
86 filter expression 'common_pid != $PERFPID' to filters. If other
87 '--filter' exists, the new filter expression will be combined with
88 them by '&&'.
89
90-a::
91--all-cpus::
92 System-wide collection from all CPUs.
93
94-p::
95--pid=::
96 Record events on existing process ID (comma separated list).
97
98-t::
99--tid=::
100 Record events on existing thread ID (comma separated list).
101 This option also disables inheritance by default. Enable it by adding
102 --inherit.
103
104-u::
105--uid=::
106 Record events in threads owned by uid. Name or number.
107
108-r::
109--realtime=::
110 Collect data with this RT SCHED_FIFO priority.
111
112--no-buffering::
113 Collect data without buffering.
114
115-c::
116--count=::
117 Event period to sample.
118
119-o::
120--output=::
121 Output file name.
122
123-i::
124--no-inherit::
125 Child tasks do not inherit counters.
126-F::
127--freq=::
128 Profile at this frequency.
129
130-m::
131--mmap-pages=::
132 Number of mmap data pages (must be a power of two) or size
133 specification with appended unit character - B/K/M/G. The
134 size is rounded up to have nearest pages power of two value.
135 Also, by adding a comma, the number of mmap pages for AUX
136 area tracing can be specified.
137
138--group::
139 Put all events in a single event group. This precedes the --event
140 option and remains only for backward compatibility. See --event.
141
142-g::
143 Enables call-graph (stack chain/backtrace) recording.
144
145--call-graph::
146 Setup and enable call-graph (stack chain/backtrace) recording,
147 implies -g. Default is "fp".
148
149 Allows specifying "fp" (frame pointer) or "dwarf"
150 (DWARF's CFI - Call Frame Information) or "lbr"
151 (Hardware Last Branch Record facility) as the method to collect
152 the information used to show the call graphs.
153
154 In some systems, where binaries are build with gcc
155 --fomit-frame-pointer, using the "fp" method will produce bogus
156 call graphs, using "dwarf", if available (perf tools linked to
157 the libunwind or libdw library) should be used instead.
158 Using the "lbr" method doesn't require any compiler options. It
159 will produce call graphs from the hardware LBR registers. The
160 main limition is that it is only available on new Intel
161 platforms, such as Haswell. It can only get user call chain. It
162 doesn't work with branch stack sampling at the same time.
163
164 When "dwarf" recording is used, perf also records (user) stack dump
165 when sampled. Default size of the stack dump is 8192 (bytes).
166 User can change the size by passing the size after comma like
167 "--call-graph dwarf,4096".
168
169-q::
170--quiet::
171 Don't print any message, useful for scripting.
172
173-v::
174--verbose::
175 Be more verbose (show counter open errors, etc).
176
177-s::
178--stat::
179 Record per-thread event counts. Use it with 'perf report -T' to see
180 the values.
181
182-d::
183--data::
184 Record the sample addresses.
185
186-T::
187--timestamp::
188 Record the sample timestamps. Use it with 'perf report -D' to see the
189 timestamps, for instance.
190
191-P::
192--period::
193 Record the sample period.
194
195-n::
196--no-samples::
197 Don't sample.
198
199-R::
200--raw-samples::
201Collect raw sample records from all opened counters (default for tracepoint counters).
202
203-C::
204--cpu::
205Collect samples only on the list of CPUs provided. Multiple CPUs can be provided as a
206comma-separated list with no space: 0,1. Ranges of CPUs are specified with -: 0-2.
207In per-thread mode with inheritance mode on (default), samples are captured only when
208the thread executes on the designated CPUs. Default is to monitor all CPUs.
209
210-B::
211--no-buildid::
212Do not save the build ids of binaries in the perf.data files. This skips
213post processing after recording, which sometimes makes the final step in
214the recording process to take a long time, as it needs to process all
215events looking for mmap records. The downside is that it can misresolve
216symbols if the workload binaries used when recording get locally rebuilt
217or upgraded, because the only key available in this case is the
218pathname. You can also set the "record.build-id" config variable to
219'skip to have this behaviour permanently.
220
221-N::
222--no-buildid-cache::
223Do not update the buildid cache. This saves some overhead in situations
224where the information in the perf.data file (which includes buildids)
225is sufficient. You can also set the "record.build-id" config variable to
226'no-cache' to have the same effect.
227
228-G name,...::
229--cgroup name,...::
230monitor only in the container (cgroup) called "name". This option is available only
231in per-cpu mode. The cgroup filesystem must be mounted. All threads belonging to
232container "name" are monitored when they run on the monitored CPUs. Multiple cgroups
233can be provided. Each cgroup is applied to the corresponding event, i.e., first cgroup
234to first event, second cgroup to second event and so on. It is possible to provide
235an empty cgroup (monitor all the time) using, e.g., -G foo,,bar. Cgroups must have
236corresponding events, i.e., they always refer to events defined earlier on the command
237line.
238
239-b::
240--branch-any::
241Enable taken branch stack sampling. Any type of taken branch may be sampled.
242This is a shortcut for --branch-filter any. See --branch-filter for more infos.
243
244-j::
245--branch-filter::
246Enable taken branch stack sampling. Each sample captures a series of consecutive
247taken branches. The number of branches captured with each sample depends on the
248underlying hardware, the type of branches of interest, and the executed code.
249It is possible to select the types of branches captured by enabling filters. The
250following filters are defined:
251
252 - any: any type of branches
253 - any_call: any function call or system call
254 - any_ret: any function return or system call return
255 - ind_call: any indirect branch
256 - call: direct calls, including far (to/from kernel) calls
257 - u: only when the branch target is at the user level
258 - k: only when the branch target is in the kernel
259 - hv: only when the target is at the hypervisor level
260 - in_tx: only when the target is in a hardware transaction
261 - no_tx: only when the target is not in a hardware transaction
262 - abort_tx: only when the target is a hardware transaction abort
263 - cond: conditional branches
264
265+
266The option requires at least one branch type among any, any_call, any_ret, ind_call, cond.
267The privilege levels may be omitted, in which case, the privilege levels of the associated
268event are applied to the branch filter. Both kernel (k) and hypervisor (hv) privilege
269levels are subject to permissions. When sampling on multiple events, branch stack sampling
270is enabled for all the sampling events. The sampled branch type is the same for all events.
271The various filters must be specified as a comma separated list: --branch-filter any_ret,u,k
272Note that this feature may not be available on all processors.
273
274--weight::
275Enable weightened sampling. An additional weight is recorded per sample and can be
276displayed with the weight and local_weight sort keys. This currently works for TSX
277abort events and some memory events in precise mode on modern Intel CPUs.
278
279--transaction::
280Record transaction flags for transaction related events.
281
282--per-thread::
283Use per-thread mmaps. By default per-cpu mmaps are created. This option
284overrides that and uses per-thread mmaps. A side-effect of that is that
285inheritance is automatically disabled. --per-thread is ignored with a warning
286if combined with -a or -C options.
287
288-D::
289--delay=::
290After starting the program, wait msecs before measuring. This is useful to
291filter out the startup phase of the program, which is often very different.
292
293-I::
294--intr-regs::
295Capture machine state (registers) at interrupt, i.e., on counter overflows for
296each sample. List of captured registers depends on the architecture. This option
297is off by default. It is possible to select the registers to sample using their
298symbolic names, e.g. on x86, ax, si. To list the available registers use
299--intr-regs=\?. To name registers, pass a comma separated list such as
300--intr-regs=ax,bx. The list of register is architecture dependent.
301
302
303--running-time::
304Record running and enabled time for read events (:S)
305
306-k::
307--clockid::
308Sets the clock id to use for the various time fields in the perf_event_type
309records. See clock_gettime(). In particular CLOCK_MONOTONIC and
310CLOCK_MONOTONIC_RAW are supported, some events might also allow
311CLOCK_BOOTTIME, CLOCK_REALTIME and CLOCK_TAI.
312
313-S::
314--snapshot::
315Select AUX area tracing Snapshot Mode. This option is valid only with an
316AUX area tracing event. Optionally the number of bytes to capture per
317snapshot can be specified. In Snapshot Mode, trace data is captured only when
318signal SIGUSR2 is received.
319
320--proc-map-timeout::
321When processing pre-existing threads /proc/XXX/mmap, it may take a long time,
322because the file may be huge. A time out is needed in such cases.
323This option sets the time out limit. The default value is 500 ms.
324
325--switch-events::
326Record context switch events i.e. events of type PERF_RECORD_SWITCH or
327PERF_RECORD_SWITCH_CPU_WIDE.
328
329--clang-path=PATH::
330Path to clang binary to use for compiling BPF scriptlets.
331(enabled when BPF support is on)
332
333--clang-opt=OPTIONS::
334Options passed to clang when compiling BPF scriptlets.
335(enabled when BPF support is on)
336
337--vmlinux=PATH::
338Specify vmlinux path which has debuginfo.
339(enabled when BPF prologue is on)
340
341--buildid-all::
342Record build-id of all DSOs regardless whether it's actually hit or not.
343
344--all-kernel::
345Configure all used events to run in kernel space.
346
347--all-user::
348Configure all used events to run in user space.
349
350SEE ALSO
351--------
352linkperf: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] [-l] [-a] <command>
12'perf record' [-e <EVENT> | --event=EVENT] [-l] [-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.
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-F::
195--freq=::
196 Profile at this frequency.
197
198-m::
199--mmap-pages=::
200 Number of mmap data pages (must be a power of two) or size
201 specification with appended unit character - B/K/M/G. The
202 size is rounded up to have nearest pages power of two value.
203 Also, by adding a comma, the number of mmap pages for AUX
204 area tracing can be specified.
205
206--group::
207 Put all events in a single event group. This precedes the --event
208 option and remains only for backward compatibility. See --event.
209
210-g::
211 Enables call-graph (stack chain/backtrace) recording.
212
213--call-graph::
214 Setup and enable call-graph (stack chain/backtrace) recording,
215 implies -g. Default is "fp".
216
217 Allows specifying "fp" (frame pointer) or "dwarf"
218 (DWARF's CFI - Call Frame Information) or "lbr"
219 (Hardware Last Branch Record facility) as the method to collect
220 the information used to show the call graphs.
221
222 In some systems, where binaries are build with gcc
223 --fomit-frame-pointer, using the "fp" method will produce bogus
224 call graphs, using "dwarf", if available (perf tools linked to
225 the libunwind or libdw library) should be used instead.
226 Using the "lbr" method doesn't require any compiler options. It
227 will produce call graphs from the hardware LBR registers. The
228 main limition is that it is only available on new Intel
229 platforms, such as Haswell. It can only get user call chain. It
230 doesn't work with branch stack sampling at the same time.
231
232 When "dwarf" recording is used, perf also records (user) stack dump
233 when sampled. Default size of the stack dump is 8192 (bytes).
234 User can change the size by passing the size after comma like
235 "--call-graph dwarf,4096".
236
237-q::
238--quiet::
239 Don't print any message, useful for scripting.
240
241-v::
242--verbose::
243 Be more verbose (show counter open errors, etc).
244
245-s::
246--stat::
247 Record per-thread event counts. Use it with 'perf report -T' to see
248 the values.
249
250-d::
251--data::
252 Record the sample addresses.
253
254-T::
255--timestamp::
256 Record the sample timestamps. Use it with 'perf report -D' to see the
257 timestamps, for instance.
258
259-P::
260--period::
261 Record the sample period.
262
263--sample-cpu::
264 Record the sample cpu.
265
266-n::
267--no-samples::
268 Don't sample.
269
270-R::
271--raw-samples::
272Collect raw sample records from all opened counters (default for tracepoint counters).
273
274-C::
275--cpu::
276Collect samples only on the list of CPUs provided. Multiple CPUs can be provided as a
277comma-separated list with no space: 0,1. Ranges of CPUs are specified with -: 0-2.
278In per-thread mode with inheritance mode on (default), samples are captured only when
279the thread executes on the designated CPUs. Default is to monitor all CPUs.
280
281-B::
282--no-buildid::
283Do not save the build ids of binaries in the perf.data files. This skips
284post processing after recording, which sometimes makes the final step in
285the recording process to take a long time, as it needs to process all
286events looking for mmap records. The downside is that it can misresolve
287symbols if the workload binaries used when recording get locally rebuilt
288or upgraded, because the only key available in this case is the
289pathname. You can also set the "record.build-id" config variable to
290'skip to have this behaviour permanently.
291
292-N::
293--no-buildid-cache::
294Do not update the buildid cache. This saves some overhead in situations
295where the information in the perf.data file (which includes buildids)
296is sufficient. You can also set the "record.build-id" config variable to
297'no-cache' to have the same effect.
298
299-G name,...::
300--cgroup name,...::
301monitor only in the container (cgroup) called "name". This option is available only
302in per-cpu mode. The cgroup filesystem must be mounted. All threads belonging to
303container "name" are monitored when they run on the monitored CPUs. Multiple cgroups
304can be provided. Each cgroup is applied to the corresponding event, i.e., first cgroup
305to first event, second cgroup to second event and so on. It is possible to provide
306an empty cgroup (monitor all the time) using, e.g., -G foo,,bar. Cgroups must have
307corresponding events, i.e., they always refer to events defined earlier on the command
308line.
309
310-b::
311--branch-any::
312Enable taken branch stack sampling. Any type of taken branch may be sampled.
313This is a shortcut for --branch-filter any. See --branch-filter for more infos.
314
315-j::
316--branch-filter::
317Enable taken branch stack sampling. Each sample captures a series of consecutive
318taken branches. The number of branches captured with each sample depends on the
319underlying hardware, the type of branches of interest, and the executed code.
320It is possible to select the types of branches captured by enabling filters. The
321following filters are defined:
322
323 - any: any type of branches
324 - any_call: any function call or system call
325 - any_ret: any function return or system call return
326 - ind_call: any indirect branch
327 - call: direct calls, including far (to/from kernel) calls
328 - u: only when the branch target is at the user level
329 - k: only when the branch target is in the kernel
330 - hv: only when the target is at the hypervisor level
331 - in_tx: only when the target is in a hardware transaction
332 - no_tx: only when the target is not in a hardware transaction
333 - abort_tx: only when the target is a hardware transaction abort
334 - cond: conditional branches
335
336+
337The option requires at least one branch type among any, any_call, any_ret, ind_call, cond.
338The privilege levels may be omitted, in which case, the privilege levels of the associated
339event are applied to the branch filter. Both kernel (k) and hypervisor (hv) privilege
340levels are subject to permissions. When sampling on multiple events, branch stack sampling
341is enabled for all the sampling events. The sampled branch type is the same for all events.
342The various filters must be specified as a comma separated list: --branch-filter any_ret,u,k
343Note that this feature may not be available on all processors.
344
345--weight::
346Enable weightened sampling. An additional weight is recorded per sample and can be
347displayed with the weight and local_weight sort keys. This currently works for TSX
348abort events and some memory events in precise mode on modern Intel CPUs.
349
350--transaction::
351Record transaction flags for transaction related events.
352
353--per-thread::
354Use per-thread mmaps. By default per-cpu mmaps are created. This option
355overrides that and uses per-thread mmaps. A side-effect of that is that
356inheritance is automatically disabled. --per-thread is ignored with a warning
357if combined with -a or -C options.
358
359-D::
360--delay=::
361After starting the program, wait msecs before measuring. This is useful to
362filter out the startup phase of the program, which is often very different.
363
364-I::
365--intr-regs::
366Capture machine state (registers) at interrupt, i.e., on counter overflows for
367each sample. List of captured registers depends on the architecture. This option
368is off by default. It is possible to select the registers to sample using their
369symbolic names, e.g. on x86, ax, si. To list the available registers use
370--intr-regs=\?. To name registers, pass a comma separated list such as
371--intr-regs=ax,bx. The list of register is architecture dependent.
372
373
374--running-time::
375Record running and enabled time for read events (:S)
376
377-k::
378--clockid::
379Sets the clock id to use for the various time fields in the perf_event_type
380records. See clock_gettime(). In particular CLOCK_MONOTONIC and
381CLOCK_MONOTONIC_RAW are supported, some events might also allow
382CLOCK_BOOTTIME, CLOCK_REALTIME and CLOCK_TAI.
383
384-S::
385--snapshot::
386Select AUX area tracing Snapshot Mode. This option is valid only with an
387AUX area tracing event. Optionally the number of bytes to capture per
388snapshot can be specified. In Snapshot Mode, trace data is captured only when
389signal SIGUSR2 is received.
390
391--proc-map-timeout::
392When processing pre-existing threads /proc/XXX/mmap, it may take a long time,
393because the file may be huge. A time out is needed in such cases.
394This option sets the time out limit. The default value is 500 ms.
395
396--switch-events::
397Record context switch events i.e. events of type PERF_RECORD_SWITCH or
398PERF_RECORD_SWITCH_CPU_WIDE.
399
400--clang-path=PATH::
401Path to clang binary to use for compiling BPF scriptlets.
402(enabled when BPF support is on)
403
404--clang-opt=OPTIONS::
405Options passed to clang when compiling BPF scriptlets.
406(enabled when BPF support is on)
407
408--vmlinux=PATH::
409Specify vmlinux path which has debuginfo.
410(enabled when BPF prologue is on)
411
412--buildid-all::
413Record build-id of all DSOs regardless whether it's actually hit or not.
414
415--all-kernel::
416Configure all used events to run in kernel space.
417
418--all-user::
419Configure all used events to run in user space.
420
421--timestamp-filename
422Append timestamp to output file name.
423
424--switch-output::
425Generate multiple perf.data files, timestamp prefixed, switching to a new one
426when receiving a SIGUSR2.
427
428A possible use case is to, given an external event, slice the perf.data file
429that gets then processed, possibly via a perf script, to decide if that
430particular perf.data snapshot should be kept or not.
431
432Implies --timestamp-filename, --no-buildid and --no-buildid-cache.
433The reason for the latter two is to reduce the data file switching
434overhead. You can still switch them on with:
435
436 --switch-output --no-no-buildid --no-no-buildid-cache
437
438--dry-run::
439Parse options then exit. --dry-run can be used to detect errors in cmdline
440options.
441
442'perf record --dry-run -e' can act as a BPF script compiler if llvm.dump-obj
443in config file is set to true.
444
445--tail-synthesize::
446Instead of collecting non-sample events (for example, fork, comm, mmap) at
447the beginning of record, collect them during finalizing an output file.
448The collected non-sample events reflects the status of the system when
449record is finished.
450
451--overwrite::
452Makes all events use an overwritable ring buffer. An overwritable ring
453buffer works like a flight recorder: when it gets full, the kernel will
454overwrite the oldest records, that thus will never make it to the
455perf.data file.
456
457When '--overwrite' and '--switch-output' are used perf records and drops
458events until it receives a signal, meaning that something unusual was
459detected that warrants taking a snapshot of the most current events,
460those fitting in the ring buffer at that moment.
461
462'overwrite' attribute can also be set or canceled for an event using
463config terms. For example: 'cycles/overwrite/' and 'instructions/no-overwrite/'.
464
465Implies --tail-synthesize.
466
467SEE ALSO
468--------
469linkperf:perf-stat[1], linkperf:perf-list[1]