1 perf-stat(1) 1 perf-stat(1)
2 ============ 2 ============
3 3
4 NAME 4 NAME
5 ---- 5 ----
6 perf-stat - Run a command and gather performan 6 perf-stat - Run a command and gather performance counter statistics
7 7
8 SYNOPSIS 8 SYNOPSIS
9 -------- 9 --------
10 [verse] 10 [verse]
11 'perf stat' [-e <EVENT> | --event=EVENT] [-a] 11 'perf stat' [-e <EVENT> | --event=EVENT] [-a] <command>
12 'perf stat' [-e <EVENT> | --event=EVENT] [-a] !! 12 'perf stat' [-e <EVENT> | --event=EVENT] [-a] -- <command> [<options>]
13 'perf stat' [-e <EVENT> | --event=EVENT] [-a] !! 13 'perf stat' [-e <EVENT> | --event=EVENT] [-a] record [-o file] -- <command> [<options>]
14 'perf stat' report [-i file] 14 'perf stat' report [-i file]
15 15
16 DESCRIPTION 16 DESCRIPTION
17 ----------- 17 -----------
18 This command runs a command and gathers perfor 18 This command runs a command and gathers performance counter statistics
19 from it. 19 from it.
20 20
21 21
22 OPTIONS 22 OPTIONS
23 ------- 23 -------
24 <command>...:: 24 <command>...::
25 Any command you can specify in a shell 25 Any command you can specify in a shell.
26 26
27 record:: 27 record::
28 See STAT RECORD. 28 See STAT RECORD.
29 29
30 report:: 30 report::
31 See STAT REPORT. 31 See STAT REPORT.
32 32
33 -e:: 33 -e::
34 --event=:: 34 --event=::
35 Select the PMU event. Selection can be 35 Select the PMU event. Selection can be:
36 36
37 - a symbolic event name (use 'perf lis 37 - a symbolic event name (use 'perf list' to list all events)
38 38
39 - a raw PMU event in the form of rN wh !! 39 - a raw PMU event (eventsel+umask) in the form of rNNN where NNN is a
40 that represents the raw register enc !! 40 hexadecimal event descriptor.
41 event control registers as described <<
42 /sys/bus/event_source/devices/cpu/fo <<
43 41
44 - a symbolic or raw PMU event followed 42 - a symbolic or raw PMU event followed by an optional colon
45 and a list of event modifiers, e.g., 43 and a list of event modifiers, e.g., cpu-cycles:p. See the
46 linkperf:perf-list[1] man page for d 44 linkperf:perf-list[1] man page for details on event modifiers.
47 45
48 - a symbolically formed event like 'pm 46 - a symbolically formed event like 'pmu/param1=0x3,param2/' where
49 param1 and param2 are defined as for 47 param1 and param2 are defined as formats for the PMU in
50 /sys/bus/event_source/devices/<pmu>/ 48 /sys/bus/event_source/devices/<pmu>/format/*
51 49
52 'percore' is a event qualifier that 50 'percore' is a event qualifier that sums up the event counts for both
53 hardware threads in a core. For exam 51 hardware threads in a core. For example:
54 perf stat -A -a -e cpu/event,percore 52 perf stat -A -a -e cpu/event,percore=1/,otherevent ...
55 53
56 - a symbolically formed event like 'pm 54 - a symbolically formed event like 'pmu/config=M,config1=N,config2=K/'
57 where M, N, K are numbers (in decima 55 where M, N, K are numbers (in decimal, hex, octal format).
58 Acceptable values for each of 'confi 56 Acceptable values for each of 'config', 'config1' and 'config2'
59 parameters are defined by correspond 57 parameters are defined by corresponding entries in
60 /sys/bus/event_source/devices/<pmu>/ 58 /sys/bus/event_source/devices/<pmu>/format/*
61 59
62 Note that the last two syntaxes suppor 60 Note that the last two syntaxes support prefix and glob matching in
63 the PMU name to simplify creation of e 61 the PMU name to simplify creation of events across multiple instances
64 of the same type of PMU in large syste 62 of the same type of PMU in large systems (e.g. memory controller PMUs).
65 Multiple PMU instances are typical for 63 Multiple PMU instances are typical for uncore PMUs, so the prefix
66 'uncore_' is also ignored when perform 64 'uncore_' is also ignored when performing this match.
67 65
68 66
69 -i:: 67 -i::
70 --no-inherit:: 68 --no-inherit::
71 child tasks do not inherit counters 69 child tasks do not inherit counters
72 -p:: 70 -p::
73 --pid=<pid>:: 71 --pid=<pid>::
74 stat events on existing process id (co 72 stat events on existing process id (comma separated list)
75 73
76 -t:: 74 -t::
77 --tid=<tid>:: 75 --tid=<tid>::
78 stat events on existing thread id (com 76 stat events on existing thread id (comma separated list)
79 77
80 -b:: 78 -b::
81 --bpf-prog:: 79 --bpf-prog::
82 stat events on existing bpf program id 80 stat events on existing bpf program id (comma separated list),
83 requiring root rights. bpftool-prog co 81 requiring root rights. bpftool-prog could be used to find program
84 id all bpf programs in the system. For 82 id all bpf programs in the system. For example:
85 83
86 # bpftool prog | head -n 1 84 # bpftool prog | head -n 1
87 17247: tracepoint name sys_enter tag 192d5 85 17247: tracepoint name sys_enter tag 192d548b9d754067 gpl
88 86
89 # perf stat -e cycles,instructions --bpf-pro 87 # perf stat -e cycles,instructions --bpf-prog 17247 --timeout 1000
90 88
91 Performance counter stats for 'BPF program( 89 Performance counter stats for 'BPF program(s) 17247':
92 90
93 85,967 cycles 91 85,967 cycles
94 28,982 instructions 92 28,982 instructions # 0.34 insn per cycle
95 93
96 1.102235068 seconds time elapsed 94 1.102235068 seconds time elapsed
97 95
98 --bpf-counters:: 96 --bpf-counters::
99 Use BPF programs to aggregate readings 97 Use BPF programs to aggregate readings from perf_events. This
100 allows multiple perf-stat sessions tha 98 allows multiple perf-stat sessions that are counting the same metric (cycles,
101 instructions, etc.) to share hardware 99 instructions, etc.) to share hardware counters.
102 To use BPF programs on common events b 100 To use BPF programs on common events by default, use
103 "perf config stat.bpf-counter-events=< 101 "perf config stat.bpf-counter-events=<list_of_events>".
104 102
105 --bpf-attr-map:: 103 --bpf-attr-map::
106 With option "--bpf-counters", differen 104 With option "--bpf-counters", different perf-stat sessions share
107 information about shared BPF programs 105 information about shared BPF programs and maps via a pinned hashmap.
108 Use "--bpf-attr-map" to specify the pa 106 Use "--bpf-attr-map" to specify the path of this pinned hashmap.
109 The default path is /sys/fs/bpf/perf_a 107 The default path is /sys/fs/bpf/perf_attr_map.
110 108
111 ifdef::HAVE_LIBPFM[] 109 ifdef::HAVE_LIBPFM[]
112 --pfm-events events:: 110 --pfm-events events::
113 Select a PMU event using libpfm4 syntax (see h 111 Select a PMU event using libpfm4 syntax (see http://perfmon2.sf.net)
114 including support for event filters. For examp 112 including support for event filters. For example '--pfm-events
115 inst_retired:any_p:u:c=1:i'. More than one eve 113 inst_retired:any_p:u:c=1:i'. More than one event can be passed to the
116 option using the comma separator. Hardware eve 114 option using the comma separator. Hardware events and generic hardware
117 events cannot be mixed together. The latter mu 115 events cannot be mixed together. The latter must be used with the -e
118 option. The -e option and this one can be mixe 116 option. The -e option and this one can be mixed and matched. Events
119 can be grouped using the {} notation. 117 can be grouped using the {} notation.
120 endif::HAVE_LIBPFM[] 118 endif::HAVE_LIBPFM[]
121 119
122 -a:: 120 -a::
123 --all-cpus:: 121 --all-cpus::
124 system-wide collection from all CPUs ( 122 system-wide collection from all CPUs (default if no target is specified)
125 123
126 --no-scale:: 124 --no-scale::
127 Don't scale/normalize counter values 125 Don't scale/normalize counter values
128 126
129 -d:: 127 -d::
130 --detailed:: 128 --detailed::
131 print more detailed statistics, can be 129 print more detailed statistics, can be specified up to 3 times
132 130
133 -d: detailed events, L1 an 131 -d: detailed events, L1 and LLC data cache
134 -d -d: more detailed events, dTLB 132 -d -d: more detailed events, dTLB and iTLB events
135 -d -d -d: very detailed events, addin 133 -d -d -d: very detailed events, adding prefetch events
136 134
137 -r:: 135 -r::
138 --repeat=<n>:: 136 --repeat=<n>::
139 repeat command and print average + std 137 repeat command and print average + stddev (max: 100). 0 means forever.
140 138
141 -B:: 139 -B::
142 --big-num:: 140 --big-num::
143 print large numbers with thousands' se 141 print large numbers with thousands' separators according to locale.
144 Enabled by default. Use "--no-big-num" 142 Enabled by default. Use "--no-big-num" to disable.
145 Default setting can be changed with "p 143 Default setting can be changed with "perf config stat.big-num=false".
146 144
147 -C:: 145 -C::
148 --cpu=:: 146 --cpu=::
149 Count only on the list of CPUs provided. Multi 147 Count only on the list of CPUs provided. Multiple CPUs can be provided as a
150 comma-separated list with no space: 0,1. Range 148 comma-separated list with no space: 0,1. Ranges of CPUs are specified with -: 0-2.
151 In per-thread mode, this option is ignored. Th 149 In per-thread mode, this option is ignored. The -a option is still necessary
152 to activate system-wide monitoring. Default is 150 to activate system-wide monitoring. Default is to count on all CPUs.
153 151
154 -A:: 152 -A::
155 --no-aggr:: 153 --no-aggr::
156 Do not aggregate counts across all monitored C 154 Do not aggregate counts across all monitored CPUs.
157 155
158 -n:: 156 -n::
159 --null:: 157 --null::
160 null run - Don't start any counters. 158 null run - Don't start any counters.
161 159
162 This can be useful to measure just elapsed wal 160 This can be useful to measure just elapsed wall-clock time - or to assess the
163 raw overhead of perf stat itself, without runn 161 raw overhead of perf stat itself, without running any counters.
164 162
165 -v:: 163 -v::
166 --verbose:: 164 --verbose::
167 be more verbose (show counter open err 165 be more verbose (show counter open errors, etc)
168 166
169 -x SEP:: 167 -x SEP::
170 --field-separator SEP:: 168 --field-separator SEP::
171 print counts using a CSV-style output to make 169 print counts using a CSV-style output to make it easy to import directly into
172 spreadsheets. Columns are separated by the str 170 spreadsheets. Columns are separated by the string specified in SEP.
173 171
174 --table:: Display time for each run (-r option 172 --table:: Display time for each run (-r option), in a table format, e.g.:
175 173
176 $ perf stat --null -r 5 --table perf bench s 174 $ perf stat --null -r 5 --table perf bench sched pipe
177 175
178 Performance counter stats for 'perf bench s 176 Performance counter stats for 'perf bench sched pipe' (5 runs):
179 177
180 # Table of individual measurement 178 # Table of individual measurements:
181 5.189 (-0.293) # 179 5.189 (-0.293) #
182 5.189 (-0.294) # 180 5.189 (-0.294) #
183 5.186 (-0.296) # 181 5.186 (-0.296) #
184 5.663 (+0.181) ## 182 5.663 (+0.181) ##
185 6.186 (+0.703) #### 183 6.186 (+0.703) ####
186 184
187 # Final result: 185 # Final result:
188 5.483 +- 0.198 seconds time elaps 186 5.483 +- 0.198 seconds time elapsed ( +- 3.62% )
189 187
190 -G name:: 188 -G name::
191 --cgroup name:: 189 --cgroup name::
192 monitor only in the container (cgroup) called 190 monitor only in the container (cgroup) called "name". This option is available only
193 in per-cpu mode. The cgroup filesystem must be 191 in per-cpu mode. The cgroup filesystem must be mounted. All threads belonging to
194 container "name" are monitored when they run o 192 container "name" are monitored when they run on the monitored CPUs. Multiple cgroups
195 can be provided. Each cgroup is applied to the 193 can be provided. Each cgroup is applied to the corresponding event, i.e., first cgroup
196 to first event, second cgroup to second event 194 to first event, second cgroup to second event and so on. It is possible to provide
197 an empty cgroup (monitor all the time) using, 195 an empty cgroup (monitor all the time) using, e.g., -G foo,,bar. Cgroups must have
198 corresponding events, i.e., they always refer 196 corresponding events, i.e., they always refer to events defined earlier on the command
199 line. If the user wants to track multiple even 197 line. If the user wants to track multiple events for a specific cgroup, the user can
200 use '-e e1 -e e2 -G foo,foo' or just use '-e e 198 use '-e e1 -e e2 -G foo,foo' or just use '-e e1 -e e2 -G foo'.
201 199
202 If wanting to monitor, say, 'cycles' for a cgr 200 If wanting to monitor, say, 'cycles' for a cgroup and also for system wide, this
203 command line can be used: 'perf stat -e cycles 201 command line can be used: 'perf stat -e cycles -G cgroup_name -a -e cycles'.
204 202
205 --for-each-cgroup name:: 203 --for-each-cgroup name::
206 Expand event list for each cgroup in "name" (a 204 Expand event list for each cgroup in "name" (allow multiple cgroups separated
207 by comma). It also support regex patterns to 205 by comma). It also support regex patterns to match multiple groups. This has same
208 effect that repeating -e option and -G option 206 effect that repeating -e option and -G option for each event x name. This option
209 cannot be used with -G/--cgroup option. 207 cannot be used with -G/--cgroup option.
210 208
211 -o file:: 209 -o file::
212 --output file:: 210 --output file::
213 Print the output into the designated file. 211 Print the output into the designated file.
214 212
215 --append:: 213 --append::
216 Append to the output file designated with the 214 Append to the output file designated with the -o option. Ignored if -o is not specified.
217 215
218 --log-fd:: 216 --log-fd::
219 217
220 Log output to fd, instead of stderr. Compleme 218 Log output to fd, instead of stderr. Complementary to --output, and mutually exclusive
221 with it. --append may be used here. Examples 219 with it. --append may be used here. Examples:
222 3>results perf stat --log-fd 3 !! 220 3>results perf stat --log-fd 3 -- $cmd
223 3>>results perf stat --log-fd 3 --append !! 221 3>>results perf stat --log-fd 3 --append -- $cmd
224 222
225 --control=fifo:ctl-fifo[,ack-fifo]:: 223 --control=fifo:ctl-fifo[,ack-fifo]::
226 --control=fd:ctl-fd[,ack-fd]:: 224 --control=fd:ctl-fd[,ack-fd]::
227 ctl-fifo / ack-fifo are opened and used as ctl 225 ctl-fifo / ack-fifo are opened and used as ctl-fd / ack-fd as follows.
228 Listen on ctl-fd descriptor for command to con 226 Listen on ctl-fd descriptor for command to control measurement ('enable': enable events,
229 'disable': disable events). Measurements can b 227 'disable': disable events). Measurements can be started with events disabled using
230 --delay=-1 option. Optionally send control com 228 --delay=-1 option. Optionally send control command completion ('ack\n') to ack-fd descriptor
231 to synchronize with the controlling process. E 229 to synchronize with the controlling process. Example of bash shell script to enable and
232 disable events during measurements: 230 disable events during measurements:
233 231
234 #!/bin/bash 232 #!/bin/bash
235 233
236 ctl_dir=/tmp/ 234 ctl_dir=/tmp/
237 235
238 ctl_fifo=${ctl_dir}perf_ctl.fifo 236 ctl_fifo=${ctl_dir}perf_ctl.fifo
239 test -p ${ctl_fifo} && unlink ${ctl_fifo} 237 test -p ${ctl_fifo} && unlink ${ctl_fifo}
240 mkfifo ${ctl_fifo} 238 mkfifo ${ctl_fifo}
241 exec {ctl_fd}<>${ctl_fifo} 239 exec {ctl_fd}<>${ctl_fifo}
242 240
243 ctl_ack_fifo=${ctl_dir}perf_ctl_ack.fifo 241 ctl_ack_fifo=${ctl_dir}perf_ctl_ack.fifo
244 test -p ${ctl_ack_fifo} && unlink ${ctl_ack_f 242 test -p ${ctl_ack_fifo} && unlink ${ctl_ack_fifo}
245 mkfifo ${ctl_ack_fifo} 243 mkfifo ${ctl_ack_fifo}
246 exec {ctl_fd_ack}<>${ctl_ack_fifo} 244 exec {ctl_fd_ack}<>${ctl_ack_fifo}
247 245
248 perf stat -D -1 -e cpu-cycles -a -I 1000 246 perf stat -D -1 -e cpu-cycles -a -I 1000 \
249 --control fd:${ctl_fd},${ctl_fd_ack 247 --control fd:${ctl_fd},${ctl_fd_ack} \
250 \-- sleep 30 & !! 248 -- sleep 30 &
251 perf_pid=$! 249 perf_pid=$!
252 250
253 sleep 5 && echo 'enable' >&${ctl_fd} && read 251 sleep 5 && echo 'enable' >&${ctl_fd} && read -u ${ctl_fd_ack} e1 && echo "enabled(${e1})"
254 sleep 10 && echo 'disable' >&${ctl_fd} && rea 252 sleep 10 && echo 'disable' >&${ctl_fd} && read -u ${ctl_fd_ack} d1 && echo "disabled(${d1})"
255 253
256 exec {ctl_fd_ack}>&- 254 exec {ctl_fd_ack}>&-
257 unlink ${ctl_ack_fifo} 255 unlink ${ctl_ack_fifo}
258 256
259 exec {ctl_fd}>&- 257 exec {ctl_fd}>&-
260 unlink ${ctl_fifo} 258 unlink ${ctl_fifo}
261 259
262 wait -n ${perf_pid} 260 wait -n ${perf_pid}
263 exit $? 261 exit $?
264 262
265 263
266 --pre:: 264 --pre::
267 --post:: 265 --post::
268 Pre and post measurement hooks, e.g.: 266 Pre and post measurement hooks, e.g.:
269 267
270 perf stat --repeat 10 --null --sync --pre 'mak !! 268 perf stat --repeat 10 --null --sync --pre 'make -s O=defconfig-build/clean' -- make -s -j64 O=defconfig-build/ bzImage
271 269
272 -I msecs:: 270 -I msecs::
273 --interval-print msecs:: 271 --interval-print msecs::
274 Print count deltas every N milliseconds (minim 272 Print count deltas every N milliseconds (minimum: 1ms)
275 The overhead percentage could be high in some 273 The overhead percentage could be high in some cases, for instance with small, sub 100ms intervals. Use with caution.
276 example: 'perf stat -I 1000 -e cycles 274 example: 'perf stat -I 1000 -e cycles -a sleep 5'
277 275
278 If the metric exists, it is calculated by the 276 If the metric exists, it is calculated by the counts generated in this interval and the metric is printed after #.
279 277
280 --interval-count times:: 278 --interval-count times::
281 Print count deltas for fixed number of times. 279 Print count deltas for fixed number of times.
282 This option should be used together with "-I" 280 This option should be used together with "-I" option.
283 example: 'perf stat -I 1000 --interval 281 example: 'perf stat -I 1000 --interval-count 2 -e cycles -a'
284 282
285 --interval-clear:: 283 --interval-clear::
286 Clear the screen before next interval. 284 Clear the screen before next interval.
287 285
288 --timeout msecs:: 286 --timeout msecs::
289 Stop the 'perf stat' session and print count d 287 Stop the 'perf stat' session and print count deltas after N milliseconds (minimum: 10 ms).
290 This option is not supported with the "-I" opt 288 This option is not supported with the "-I" option.
291 example: 'perf stat --time 2000 -e cyc 289 example: 'perf stat --time 2000 -e cycles -a'
292 290
293 --metric-only:: 291 --metric-only::
294 Only print computed metrics. Print them in a s 292 Only print computed metrics. Print them in a single line.
295 Don't show any raw values. Not supported with 293 Don't show any raw values. Not supported with --per-thread.
296 294
297 --per-socket:: 295 --per-socket::
298 Aggregate counts per processor socket for syst 296 Aggregate counts per processor socket for system-wide mode measurements. This
299 is a useful mode to detect imbalance between s 297 is a useful mode to detect imbalance between sockets. To enable this mode,
300 use --per-socket in addition to -a. (system-wi 298 use --per-socket in addition to -a. (system-wide). The output includes the
301 socket number and the number of online process 299 socket number and the number of online processors on that socket. This is
302 useful to gauge the amount of aggregation. 300 useful to gauge the amount of aggregation.
303 301
304 --per-die:: 302 --per-die::
305 Aggregate counts per processor die for system- 303 Aggregate counts per processor die for system-wide mode measurements. This
306 is a useful mode to detect imbalance between d 304 is a useful mode to detect imbalance between dies. To enable this mode,
307 use --per-die in addition to -a. (system-wide) 305 use --per-die in addition to -a. (system-wide). The output includes the
308 die number and the number of online processors 306 die number and the number of online processors on that die. This is
309 useful to gauge the amount of aggregation. 307 useful to gauge the amount of aggregation.
310 308
311 --per-cluster:: <<
312 Aggregate counts per processor cluster for sys <<
313 is a useful mode to detect imbalance between c <<
314 use --per-cluster in addition to -a. (system-w <<
315 cluster number and the number of online proces <<
316 useful to gauge the amount of aggregation. The <<
317 related CPUs can be gotten from /sys/devices/s <<
318 <<
319 --per-cache:: <<
320 Aggregate counts per cache instance for system <<
321 default, the aggregation happens for the cache <<
322 in the system. To specify a particular level, <<
323 alongside the option in the format [Ll][1-9][0 <<
324 Using option "--per-cache=l3" or "--per-cache= <<
325 information at the boundary of the level 3 cac <<
326 <<
327 --per-core:: 309 --per-core::
328 Aggregate counts per physical processor for sy 310 Aggregate counts per physical processor for system-wide mode measurements. This
329 is a useful mode to detect imbalance between p 311 is a useful mode to detect imbalance between physical cores. To enable this mode,
330 use --per-core in addition to -a. (system-wide 312 use --per-core in addition to -a. (system-wide). The output includes the
331 core number and the number of online logical p 313 core number and the number of online logical processors on that physical processor.
332 314
333 --per-thread:: 315 --per-thread::
334 Aggregate counts per monitored threads, when m 316 Aggregate counts per monitored threads, when monitoring threads (-t option)
335 or processes (-p option). 317 or processes (-p option).
336 318
337 --per-node:: 319 --per-node::
338 Aggregate counts per NUMA nodes for system-wid 320 Aggregate counts per NUMA nodes for system-wide mode measurements. This
339 is a useful mode to detect imbalance between N 321 is a useful mode to detect imbalance between NUMA nodes. To enable this
340 mode, use --per-node in addition to -a. (syste 322 mode, use --per-node in addition to -a. (system-wide).
341 323
342 -D msecs:: 324 -D msecs::
343 --delay msecs:: 325 --delay msecs::
344 After starting the program, wait msecs before 326 After starting the program, wait msecs before measuring (-1: start with events
345 disabled). This is useful to filter out the st 327 disabled). This is useful to filter out the startup phase of the program,
346 which is often very different. 328 which is often very different.
347 329
348 -T:: 330 -T::
349 --transaction:: 331 --transaction::
350 332
351 Print statistics of transactional execution if 333 Print statistics of transactional execution if supported.
352 334
353 --metric-no-group:: 335 --metric-no-group::
354 By default, events to compute a metric are pla 336 By default, events to compute a metric are placed in weak groups. The
355 group tries to enforce scheduling all or none 337 group tries to enforce scheduling all or none of the events. The
356 --metric-no-group option places events outside 338 --metric-no-group option places events outside of groups and may
357 increase the chance of the event being schedul 339 increase the chance of the event being scheduled - leading to more
358 accuracy. However, as events may not be schedu 340 accuracy. However, as events may not be scheduled together accuracy
359 for metrics like instructions per cycle can be 341 for metrics like instructions per cycle can be lower - as both metrics
360 may no longer be being measured at the same ti 342 may no longer be being measured at the same time.
361 343
362 --metric-no-merge:: 344 --metric-no-merge::
363 By default metric events in different weak gro 345 By default metric events in different weak groups can be shared if one
364 group contains all the events needed by anothe 346 group contains all the events needed by another. In such cases one
365 group will be eliminated reducing event multip 347 group will be eliminated reducing event multiplexing and making it so
366 that certain groups of metrics sum to 100%. A 348 that certain groups of metrics sum to 100%. A downside to sharing a
367 group is that the group may require multiplexi 349 group is that the group may require multiplexing and so accuracy for a
368 small group that need not have multiplexing is 350 small group that need not have multiplexing is lowered. This option
369 forbids the event merging logic from sharing e 351 forbids the event merging logic from sharing events between groups and
370 may be used to increase accuracy in this case. 352 may be used to increase accuracy in this case.
371 353
372 --metric-no-threshold:: <<
373 Metric thresholds may increase the number of e <<
374 compute whether a metric has exceeded its thre <<
375 may not be desirable, for example, as the even <<
376 multiplexing. This option disables the adding <<
377 events for a metric. However, if there are suf <<
378 compute the threshold then the threshold is st <<
379 color the metric's computed value. <<
380 <<
381 --quiet:: 354 --quiet::
382 Don't print output, warnings or messages. This !! 355 Don't print output. This is useful with perf stat record below to only
383 record below to only write data to the perf.da !! 356 write data to the perf.data file.
384 357
385 STAT RECORD 358 STAT RECORD
386 ----------- 359 -----------
387 Stores stat data into perf data file. 360 Stores stat data into perf data file.
388 361
389 -o file:: 362 -o file::
390 --output file:: 363 --output file::
391 Output file name. 364 Output file name.
392 365
393 STAT REPORT 366 STAT REPORT
394 ----------- 367 -----------
395 Reads and reports stat data from perf data fil 368 Reads and reports stat data from perf data file.
396 369
397 -i file:: 370 -i file::
398 --input file:: 371 --input file::
399 Input file name. 372 Input file name.
400 373
401 --per-socket:: 374 --per-socket::
402 Aggregate counts per processor socket for syst 375 Aggregate counts per processor socket for system-wide mode measurements.
403 376
404 --per-die:: 377 --per-die::
405 Aggregate counts per processor die for system- 378 Aggregate counts per processor die for system-wide mode measurements.
406 379
407 --per-cluster:: <<
408 Aggregate counts perf processor cluster for sy <<
409 <<
410 --per-cache:: <<
411 Aggregate counts per cache instance for system <<
412 default, the aggregation happens for the cache <<
413 in the system. To specify a particular level, <<
414 alongside the option in the format [Ll][1-9][0 <<
415 option "--per-cache=l3" or "--per-cache=L3" wi <<
416 information at the boundary of the level 3 cac <<
417 <<
418 --per-core:: 380 --per-core::
419 Aggregate counts per physical processor for sy 381 Aggregate counts per physical processor for system-wide mode measurements.
420 382
421 -M:: 383 -M::
422 --metrics:: 384 --metrics::
423 Print metrics or metricgroups specified in a c 385 Print metrics or metricgroups specified in a comma separated list.
424 For a group all metrics from the group are add 386 For a group all metrics from the group are added.
425 The events from the metrics are automatically 387 The events from the metrics are automatically measured.
426 See perf list output for the possible metrics !! 388 See perf list output for the possble metrics and metricgroups.
427 <<
428 When threshold information is availabl <<
429 color red is used to signify a metric <<
430 while green shows it hasn't. The defau <<
431 no threshold information was available <<
432 couldn't be computed. <<
433 389
434 -A:: 390 -A::
435 --no-aggr:: 391 --no-aggr::
436 --no-merge:: !! 392 Do not aggregate counts across all monitored CPUs.
437 Do not aggregate/merge counts across monitored <<
438 <<
439 When multiple events are created from a single <<
440 stat will, by default, aggregate the event cou <<
441 in a single row. This option disables that beh <<
442 individual events and counts. <<
443 <<
444 Multiple events are created from a single even <<
445 <<
446 1. PID monitoring isn't requested and the syst <<
447 CPU. For example, a system with 8 SMT threa <<
448 opened on each thread and aggregation is pe <<
449 <<
450 2. Prefix or glob wildcard matching is used fo <<
451 example, multiple memory controller PMUs ma <<
452 suffix of _0, _1, etc. By default the event <<
453 combined if the PMU is specified without th <<
454 uncore_imc rather than uncore_imc_0. <<
455 <<
456 3. Aliases, which are listed immediately after <<
457 by perf list, are used. <<
458 <<
459 --hybrid-merge:: <<
460 Merge core event counts from all core PMUs. In <<
461 systems by default each core PMU will report i <<
462 separately. This option forces core PMU counts <<
463 a behavior closer to having a single CPU type <<
464 393
465 --topdown:: 394 --topdown::
466 Print top-down metrics supported by the CPU. T !! 395 Print complete top-down metrics supported by the CPU. This allows to
467 bottle necks in the CPU pipeline for CPU bound !! 396 determine bottle necks in the CPU pipeline for CPU bound workloads,
468 the cycles consumed down into frontend bound, !! 397 by breaking the cycles consumed down into frontend bound, backend bound,
469 speculation and retiring. !! 398 bad speculation and retiring.
470 399
471 Frontend bound means that the CPU cannot fetch 400 Frontend bound means that the CPU cannot fetch and decode instructions fast
472 enough. Backend bound means that computation o 401 enough. Backend bound means that computation or memory access is the bottle
473 neck. Bad Speculation means that the CPU waste 402 neck. Bad Speculation means that the CPU wasted cycles due to branch
474 mispredictions and similar issues. Retiring me 403 mispredictions and similar issues. Retiring means that the CPU computed without
475 an apparently bottleneck. The bottleneck is on 404 an apparently bottleneck. The bottleneck is only the real bottleneck
476 if the workload is actually bound by the CPU a 405 if the workload is actually bound by the CPU and not by something else.
477 406
478 For best results it is usually a good idea to 407 For best results it is usually a good idea to use it with interval
479 mode like -I 1000, as the bottleneck of worklo 408 mode like -I 1000, as the bottleneck of workloads can change often.
480 409
481 This enables --metric-only, unless overridden 410 This enables --metric-only, unless overridden with --no-metric-only.
482 411
483 The following restrictions only apply to older 412 The following restrictions only apply to older Intel CPUs and Atom,
484 on newer CPUs (IceLake and later) TopDown can 413 on newer CPUs (IceLake and later) TopDown can be collected for any thread:
485 414
486 The top down metrics are collected per core in 415 The top down metrics are collected per core instead of per
487 CPU thread. Per core mode is automatically ena 416 CPU thread. Per core mode is automatically enabled
488 and -a (global monitoring) is needed, requirin 417 and -a (global monitoring) is needed, requiring root rights or
489 perf.perf_event_paranoid=-1. 418 perf.perf_event_paranoid=-1.
490 419
491 Topdown uses the full Performance Monitoring U 420 Topdown uses the full Performance Monitoring Unit, and needs
492 disabling of the NMI watchdog (as root): 421 disabling of the NMI watchdog (as root):
493 echo 0 > /proc/sys/kernel/nmi_watchdog 422 echo 0 > /proc/sys/kernel/nmi_watchdog
494 for best results. Otherwise the bottlenecks ma 423 for best results. Otherwise the bottlenecks may be inconsistent
495 on workload with changing phases. 424 on workload with changing phases.
496 425
497 To interpret the results it is usually needed 426 To interpret the results it is usually needed to know on which
498 CPUs the workload runs on. If needed the CPUs 427 CPUs the workload runs on. If needed the CPUs can be forced using
499 taskset. 428 taskset.
500 429
501 --record-tpebs:: <<
502 Enable automatic sampling on Intel TPEBS retir <<
503 modifier). Without this option, perf would not <<
504 at runtime. Currently, a zero value is assigne <<
505 this option is not set. The TPEBS hardware fea <<
506 Rapids microarchitecture. This option only exi <<
507 Intel platforms with TPEBS feature. <<
508 <<
509 --td-level:: 430 --td-level::
510 Print the top-down statistics that equal the i !! 431 Print the top-down statistics that equal to or lower than the input level.
511 users to print the interested top-down metrics !! 432 It allows users to print the interested top-down metrics level instead of
512 level 1 top-down metrics. !! 433 the complete top-down metrics.
513 !! 434
514 As the higher levels gather more metrics and u !! 435 The availability of the top-down metrics level depends on the hardware. For
515 will be less accurate. By convention a metric !! 436 example, Ice Lake only supports L1 top-down metrics. The Sapphire Rapids
516 appending '_group' to it and this will increas !! 437 supports both L1 and L2 top-down metrics.
517 gathering all metrics for a level. For example <<
518 highlight 'tma_frontend_bound'. This metric ma <<
519 'tma_frontend_bound_group' with <<
520 'perf stat -M tma_frontend_bound_group...'. <<
521 438
>> 439 Default: 0 means the max level that the current hardware support.
522 Error out if the input is higher than the supp 440 Error out if the input is higher than the supported max level.
523 441
>> 442 --no-merge::
>> 443 Do not merge results from same PMUs.
>> 444
>> 445 When multiple events are created from a single event specification,
>> 446 stat will, by default, aggregate the event counts and show the result
>> 447 in a single row. This option disables that behavior and shows
>> 448 the individual events and counts.
>> 449
>> 450 Multiple events are created from a single event specification when:
>> 451 1. Prefix or glob matching is used for the PMU name.
>> 452 2. Aliases, which are listed immediately after the Kernel PMU events
>> 453 by perf list, are used.
>> 454
524 --smi-cost:: 455 --smi-cost::
525 Measure SMI cost if msr/aperf/ and msr/smi/ ev 456 Measure SMI cost if msr/aperf/ and msr/smi/ events are supported.
526 457
527 During the measurement, the /sys/device/cpu/fr 458 During the measurement, the /sys/device/cpu/freeze_on_smi will be set to
528 freeze core counters on SMI. 459 freeze core counters on SMI.
529 The aperf counter will not be effected by the 460 The aperf counter will not be effected by the setting.
530 The cost of SMI can be measured by (aperf - un 461 The cost of SMI can be measured by (aperf - unhalted core cycles).
531 462
532 In practice, the percentages of SMI cycles is 463 In practice, the percentages of SMI cycles is very useful for performance
533 oriented analysis. --metric_only will be appli 464 oriented analysis. --metric_only will be applied by default.
534 The output is SMI cycles%, equals to (aperf - 465 The output is SMI cycles%, equals to (aperf - unhalted core cycles) / aperf
535 466
536 Users who wants to get the actual value can ap 467 Users who wants to get the actual value can apply --no-metric-only.
537 468
538 --all-kernel:: 469 --all-kernel::
539 Configure all used events to run in kernel spa 470 Configure all used events to run in kernel space.
540 471
541 --all-user:: 472 --all-user::
542 Configure all used events to run in user space 473 Configure all used events to run in user space.
543 474
544 --percore-show-thread:: 475 --percore-show-thread::
545 The event modifier "percore" has supported to 476 The event modifier "percore" has supported to sum up the event counts
546 for all hardware threads in a core and show th 477 for all hardware threads in a core and show the counts per core.
547 478
548 This option with event modifier "percore" enab 479 This option with event modifier "percore" enabled also sums up the event
549 counts for all hardware threads in a core but 480 counts for all hardware threads in a core but show the sum counts per
550 hardware thread. This is essentially a replace 481 hardware thread. This is essentially a replacement for the any bit and
551 convenient for post processing. 482 convenient for post processing.
552 483
553 --summary:: 484 --summary::
554 Print summary for interval mode (-I). 485 Print summary for interval mode (-I).
555 486
556 --no-csv-summary:: 487 --no-csv-summary::
557 Don't print 'summary' at the first column for 488 Don't print 'summary' at the first column for CVS summary output.
558 This option must be used with -x and --summary 489 This option must be used with -x and --summary.
559 490
560 This option can be enabled in perf config by s 491 This option can be enabled in perf config by setting the variable
561 'stat.no-csv-summary'. 492 'stat.no-csv-summary'.
562 493
563 $ perf config stat.no-csv-summary=true 494 $ perf config stat.no-csv-summary=true
564 495
565 --cputype:: <<
566 Only enable events on applying cpu with this t <<
567 (e.g. core or atom)" <<
568 <<
569 EXAMPLES 496 EXAMPLES
570 -------- 497 --------
571 498
572 $ perf stat \-- make !! 499 $ perf stat -- make
573 500
574 Performance counter stats for 'make': 501 Performance counter stats for 'make':
575 502
576 83723.452481 task-clock:u (msec) 503 83723.452481 task-clock:u (msec) # 1.004 CPUs utilized
577 0 context-switches:u 504 0 context-switches:u # 0.000 K/sec
578 0 cpu-migrations:u 505 0 cpu-migrations:u # 0.000 K/sec
579 3,228,188 page-faults:u 506 3,228,188 page-faults:u # 0.039 M/sec
580 229,570,665,834 cycles:u 507 229,570,665,834 cycles:u # 2.742 GHz
581 313,163,853,778 instructions:u 508 313,163,853,778 instructions:u # 1.36 insn per cycle
582 69,704,684,856 branches:u 509 69,704,684,856 branches:u # 832.559 M/sec
583 2,078,861,393 branch-misses:u 510 2,078,861,393 branch-misses:u # 2.98% of all branches
584 511
585 83.409183620 seconds time elapsed 512 83.409183620 seconds time elapsed
586 513
587 74.684747000 seconds user 514 74.684747000 seconds user
588 8.739217000 seconds sys 515 8.739217000 seconds sys
589 516
590 TIMINGS 517 TIMINGS
591 ------- 518 -------
592 As displayed in the example above we can displ 519 As displayed in the example above we can display 3 types of timings.
593 We always display the time the counters were e 520 We always display the time the counters were enabled/alive:
594 521
595 83.409183620 seconds time elapsed 522 83.409183620 seconds time elapsed
596 523
597 For workload sessions we also display time the 524 For workload sessions we also display time the workloads spent in
598 user/system lands: 525 user/system lands:
599 526
600 74.684747000 seconds user 527 74.684747000 seconds user
601 8.739217000 seconds sys 528 8.739217000 seconds sys
602 529
603 Those times are the very same as displayed by 530 Those times are the very same as displayed by the 'time' tool.
604 531
605 CSV FORMAT 532 CSV FORMAT
606 ---------- 533 ----------
607 534
608 With -x, perf stat is able to output a not-qui 535 With -x, perf stat is able to output a not-quite-CSV format output
609 Commas in the output are not put into "". To m 536 Commas in the output are not put into "". To make it easy to parse
610 it is recommended to use a different character 537 it is recommended to use a different character like -x \;
611 538
612 The fields are in this order: 539 The fields are in this order:
613 540
614 - optional usec time stamp in fraction 541 - optional usec time stamp in fractions of second (with -I xxx)
615 - optional CPU, core, or socket identi 542 - optional CPU, core, or socket identifier
616 - optional number of logical CPUs aggr 543 - optional number of logical CPUs aggregated
617 - counter value 544 - counter value
618 - unit of the counter value or empty 545 - unit of the counter value or empty
619 - event name 546 - event name
620 - run time of counter 547 - run time of counter
621 - percentage of measurement time the c 548 - percentage of measurement time the counter was running
622 - optional variance if multiple values 549 - optional variance if multiple values are collected with -r
623 - optional metric value 550 - optional metric value
624 - optional unit of metric 551 - optional unit of metric
625 552
626 Additional metrics may be printed with all ear 553 Additional metrics may be printed with all earlier fields being empty.
627 554
628 include::intel-hybrid.txt[] 555 include::intel-hybrid.txt[]
629 <<
630 JSON FORMAT <<
631 ----------- <<
632 <<
633 With -j, perf stat is able to print out a JSON <<
634 that can be used for parsing. <<
635 <<
636 - timestamp : optional usec time stamp in frac <<
637 - optional aggregate options: <<
638 - core : core identifier (with <<
639 - die : die identifier (with - <<
640 - socket : socket identifier ( <<
641 - node : node identifier (with <<
642 - thread : thread identifier ( <<
643 - counter-value : counter value <<
644 - unit : unit of the counter value or empty <<
645 - event : event name <<
646 - variance : optional variance if multiple val <<
647 - runtime : run time of counter <<
648 - metric-value : optional metric value <<
649 - metric-unit : optional unit of metric <<
650 556
651 SEE ALSO 557 SEE ALSO
652 -------- 558 --------
653 linkperf:perf-top[1], linkperf:perf-list[1] 559 linkperf:perf-top[1], linkperf:perf-list[1]
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