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1perf-top(1)
2===========
3
4NAME
5----
6perf-top - System profiling tool.
7
8SYNOPSIS
9--------
10[verse]
11'perf top' [-e <EVENT> | --event=EVENT] [<options>]
12
13DESCRIPTION
14-----------
15This command generates and displays a performance counter profile in real time.
16
17
18OPTIONS
19-------
20-a::
21--all-cpus::
22 System-wide collection. (default)
23
24-c <count>::
25--count=<count>::
26 Event period to sample.
27
28-C <cpu-list>::
29--cpu=<cpu>::
30Monitor only on the list of CPUs provided. Multiple CPUs can be provided as a
31comma-separated list with no space: 0,1. Ranges of CPUs are specified with -: 0-2.
32Default is to monitor all CPUS.
33
34-d <seconds>::
35--delay=<seconds>::
36 Number of seconds to delay between refreshes.
37
38-e <event>::
39--event=<event>::
40 Select the PMU event. Selection can be a symbolic event name
41 (use 'perf list' to list all events) or a raw PMU event in the form
42 of rN where N is a hexadecimal value that represents the raw register
43 encoding with the layout of the event control registers as described
44 by entries in /sys/bus/event_source/devices/cpu/format/*.
45
46-E <entries>::
47--entries=<entries>::
48 Display this many functions.
49
50-f <count>::
51--count-filter=<count>::
52 Only display functions with more events than this.
53
54--group-sort-idx::
55 Sort the output by the event at the index n in group. If n is invalid,
56 sort by the first event. It can support multiple groups with different
57 amount of events. WARNING: This should be used on grouped events.
58
59-F <freq>::
60--freq=<freq>::
61 Profile at this frequency. Use 'max' to use the currently maximum
62 allowed frequency, i.e. the value in the kernel.perf_event_max_sample_rate
63 sysctl.
64
65-i::
66--inherit::
67 Child tasks do not inherit counters.
68
69-k <path>::
70--vmlinux=<path>::
71 Path to vmlinux. Required for annotation functionality.
72
73--ignore-vmlinux::
74 Ignore vmlinux files.
75
76--kallsyms=<file>::
77 kallsyms pathname
78
79-m <pages>::
80--mmap-pages=<pages>::
81 Number of mmap data pages (must be a power of two) or size
82 specification with appended unit character - B/K/M/G. The
83 size is rounded up to have nearest pages power of two value.
84
85-p <pid>::
86--pid=<pid>::
87 Profile events on existing Process ID (comma separated list).
88
89-t <tid>::
90--tid=<tid>::
91 Profile events on existing thread ID (comma separated list).
92
93-u::
94--uid=::
95 Record events in threads owned by uid. Name or number.
96
97-r <priority>::
98--realtime=<priority>::
99 Collect data with this RT SCHED_FIFO priority.
100
101--sym-annotate=<symbol>::
102 Annotate this symbol.
103
104-K::
105--hide_kernel_symbols::
106 Hide kernel symbols.
107
108-U::
109--hide_user_symbols::
110 Hide user symbols.
111
112--demangle-kernel::
113 Demangle kernel symbols.
114
115-D::
116--dump-symtab::
117 Dump the symbol table used for profiling.
118
119-v::
120--verbose::
121 Be more verbose (show counter open errors, etc).
122
123-z::
124--zero::
125 Zero history across display updates.
126
127-s::
128--sort::
129 Sort by key(s): pid, comm, dso, symbol, parent, srcline, weight,
130 local_weight, abort, in_tx, transaction, overhead, sample, period.
131 Please see description of --sort in the perf-report man page.
132
133--fields=::
134 Specify output field - multiple keys can be specified in CSV format.
135 Following fields are available:
136 overhead, overhead_sys, overhead_us, overhead_children, sample and period.
137 Also it can contain any sort key(s).
138
139 By default, every sort keys not specified in --field will be appended
140 automatically.
141
142-n::
143--show-nr-samples::
144 Show a column with the number of samples.
145
146--show-total-period::
147 Show a column with the sum of periods.
148
149--dsos::
150 Only consider symbols in these dsos. This option will affect the
151 percentage of the overhead column. See --percentage for more info.
152
153--comms::
154 Only consider symbols in these comms. This option will affect the
155 percentage of the overhead column. See --percentage for more info.
156
157--symbols::
158 Only consider these symbols. This option will affect the
159 percentage of the overhead column. See --percentage for more info.
160
161-M::
162--disassembler-style=:: Set disassembler style for objdump.
163
164--prefix=PREFIX::
165--prefix-strip=N::
166 Remove first N entries from source file path names in executables
167 and add PREFIX. This allows to display source code compiled on systems
168 with different file system layout.
169
170--source::
171 Interleave source code with assembly code. Enabled by default,
172 disable with --no-source.
173
174--asm-raw::
175 Show raw instruction encoding of assembly instructions.
176
177-g::
178 Enables call-graph (stack chain/backtrace) recording.
179
180--call-graph [mode,type,min[,limit],order[,key][,branch]]::
181 Setup and enable call-graph (stack chain/backtrace) recording,
182 implies -g. See `--call-graph` section in perf-record and
183 perf-report man pages for details.
184
185--children::
186 Accumulate callchain of children to parent entry so that then can
187 show up in the output. The output will have a new "Children" column
188 and will be sorted on the data. It requires -g/--call-graph option
189 enabled. See the `overhead calculation' section for more details.
190 Enabled by default, disable with --no-children.
191
192--max-stack::
193 Set the stack depth limit when parsing the callchain, anything
194 beyond the specified depth will be ignored. This is a trade-off
195 between information loss and faster processing especially for
196 workloads that can have a very long callchain stack.
197
198 Default: /proc/sys/kernel/perf_event_max_stack when present, 127 otherwise.
199
200--ignore-callees=<regex>::
201 Ignore callees of the function(s) matching the given regex.
202 This has the effect of collecting the callers of each such
203 function into one place in the call-graph tree.
204
205--percent-limit::
206 Do not show entries which have an overhead under that percent.
207 (Default: 0).
208
209--percentage::
210 Determine how to display the overhead percentage of filtered entries.
211 Filters can be applied by --comms, --dsos and/or --symbols options and
212 Zoom operations on the TUI (thread, dso, etc).
213
214 "relative" means it's relative to filtered entries only so that the
215 sum of shown entries will be always 100%. "absolute" means it retains
216 the original value before and after the filter is applied.
217
218-w::
219--column-widths=<width[,width...]>::
220 Force each column width to the provided list, for large terminal
221 readability. 0 means no limit (default behavior).
222
223--proc-map-timeout::
224 When processing pre-existing threads /proc/XXX/mmap, it may take
225 a long time, because the file may be huge. A time out is needed
226 in such cases.
227 This option sets the time out limit. The default value is 500 ms.
228
229
230-b::
231--branch-any::
232 Enable taken branch stack sampling. Any type of taken branch may be sampled.
233 This is a shortcut for --branch-filter any. See --branch-filter for more infos.
234
235-j::
236--branch-filter::
237 Enable taken branch stack sampling. Each sample captures a series of consecutive
238 taken branches. The number of branches captured with each sample depends on the
239 underlying hardware, the type of branches of interest, and the executed code.
240 It is possible to select the types of branches captured by enabling filters.
241 For a full list of modifiers please see the perf record manpage.
242
243 The option requires at least one branch type among any, any_call, any_ret, ind_call, cond.
244 The privilege levels may be omitted, in which case, the privilege levels of the associated
245 event are applied to the branch filter. Both kernel (k) and hypervisor (hv) privilege
246 levels are subject to permissions. When sampling on multiple events, branch stack sampling
247 is enabled for all the sampling events. The sampled branch type is the same for all events.
248 The various filters must be specified as a comma separated list: --branch-filter any_ret,u,k
249 Note that this feature may not be available on all processors.
250
251--raw-trace::
252 When displaying traceevent output, do not use print fmt or plugins.
253
254--hierarchy::
255 Enable hierarchy output.
256
257--overwrite::
258 Enable this to use just the most recent records, which helps in high core count
259 machines such as Knights Landing/Mill, but right now is disabled by default as
260 the pausing used in this technique is leading to loss of metadata events such
261 as PERF_RECORD_MMAP which makes 'perf top' unable to resolve samples, leading
262 to lots of unknown samples appearing on the UI. Enable this if you are in such
263 machines and profiling a workload that doesn't creates short lived threads and/or
264 doesn't uses many executable mmap operations. Work is being planed to solve
265 this situation, till then, this will remain disabled by default.
266
267--force::
268 Don't do ownership validation.
269
270--num-thread-synthesize::
271 The number of threads to run when synthesizing events for existing processes.
272 By default, the number of threads equals to the number of online CPUs.
273
274--namespaces::
275 Record events of type PERF_RECORD_NAMESPACES and display it with the
276 'cgroup_id' sort key.
277
278-G name::
279--cgroup name::
280monitor only in the container (cgroup) called "name". This option is available only
281in per-cpu mode. The cgroup filesystem must be mounted. All threads belonging to
282container "name" are monitored when they run on the monitored CPUs. Multiple cgroups
283can be provided. Each cgroup is applied to the corresponding event, i.e., first cgroup
284to first event, second cgroup to second event and so on. It is possible to provide
285an empty cgroup (monitor all the time) using, e.g., -G foo,,bar. Cgroups must have
286corresponding events, i.e., they always refer to events defined earlier on the command
287line. If the user wants to track multiple events for a specific cgroup, the user can
288use '-e e1 -e e2 -G foo,foo' or just use '-e e1 -e e2 -G foo'.
289
290--all-cgroups::
291 Record events of type PERF_RECORD_CGROUP and display it with the
292 'cgroup' sort key.
293
294--switch-on EVENT_NAME::
295 Only consider events after this event is found.
296
297 E.g.:
298
299 Find out where broadcast packets are handled
300
301 perf probe -L icmp_rcv
302
303 Insert a probe there:
304
305 perf probe icmp_rcv:59
306
307 Start perf top and ask it to only consider the cycles events when a
308 broadcast packet arrives This will show a menu with two entries and
309 will start counting when a broadcast packet arrives:
310
311 perf top -e cycles,probe:icmp_rcv --switch-on=probe:icmp_rcv
312
313 Alternatively one can ask for a group and then two overhead columns
314 will appear, the first for cycles and the second for the switch-on event.
315
316 perf top -e '{cycles,probe:icmp_rcv}' --switch-on=probe:icmp_rcv
317
318 This may be interesting to measure a workload only after some initialization
319 phase is over, i.e. insert a perf probe at that point and use the above
320 examples replacing probe:icmp_rcv with the just-after-init probe.
321
322--switch-off EVENT_NAME::
323 Stop considering events after this event is found.
324
325--show-on-off-events::
326 Show the --switch-on/off events too. This has no effect in 'perf top' now
327 but probably we'll make the default not to show the switch-on/off events
328 on the --group mode and if there is only one event besides the off/on ones,
329 go straight to the histogram browser, just like 'perf top' with no events
330 explicitly specified does.
331
332--stitch-lbr::
333 Show callgraph with stitched LBRs, which may have more complete
334 callgraph. The option must be used with --call-graph lbr recording.
335 Disabled by default. In common cases with call stack overflows,
336 it can recreate better call stacks than the default lbr call stack
337 output. But this approach is not full proof. There can be cases
338 where it creates incorrect call stacks from incorrect matches.
339 The known limitations include exception handing such as
340 setjmp/longjmp will have calls/returns not match.
341
342ifdef::HAVE_LIBPFM[]
343--pfm-events events::
344Select a PMU event using libpfm4 syntax (see http://perfmon2.sf.net)
345including support for event filters. For example '--pfm-events
346inst_retired:any_p:u:c=1:i'. More than one event can be passed to the
347option using the comma separator. Hardware events and generic hardware
348events cannot be mixed together. The latter must be used with the -e
349option. The -e option and this one can be mixed and matched. Events
350can be grouped using the {} notation.
351endif::HAVE_LIBPFM[]
352
353INTERACTIVE PROMPTING KEYS
354--------------------------
355
356[d]::
357 Display refresh delay.
358
359[e]::
360 Number of entries to display.
361
362[E]::
363 Event to display when multiple counters are active.
364
365[f]::
366 Profile display filter (>= hit count).
367
368[F]::
369 Annotation display filter (>= % of total).
370
371[s]::
372 Annotate symbol.
373
374[S]::
375 Stop annotation, return to full profile display.
376
377[K]::
378 Hide kernel symbols.
379
380[U]::
381 Hide user symbols.
382
383[z]::
384 Toggle event count zeroing across display updates.
385
386[qQ]::
387 Quit.
388
389Pressing any unmapped key displays a menu, and prompts for input.
390
391include::callchain-overhead-calculation.txt[]
392
393SEE ALSO
394--------
395linkperf:perf-stat[1], linkperf:perf-list[1], linkperf:perf-report[1]
1perf-top(1)
2===========
3
4NAME
5----
6perf-top - System profiling tool.
7
8SYNOPSIS
9--------
10[verse]
11'perf top' [-e <EVENT> | --event=EVENT] [<options>]
12
13DESCRIPTION
14-----------
15This command generates and displays a performance counter profile in real time.
16
17
18OPTIONS
19-------
20-a::
21--all-cpus::
22 System-wide collection. (default)
23
24-c <count>::
25--count=<count>::
26 Event period to sample.
27
28-C <cpu-list>::
29--cpu=<cpu>::
30Monitor only on the list of CPUs provided. Multiple CPUs can be provided as a
31comma-separated list with no space: 0,1. Ranges of CPUs are specified with -: 0-2.
32Default is to monitor all CPUS.
33
34-d <seconds>::
35--delay=<seconds>::
36 Number of seconds to delay between refreshes.
37
38-e <event>::
39--event=<event>::
40 Select the PMU event. Selection can be a symbolic event name
41 (use 'perf list' to list all events) or a raw PMU
42 event (eventsel+umask) in the form of rNNN where NNN is a
43 hexadecimal event descriptor.
44
45-E <entries>::
46--entries=<entries>::
47 Display this many functions.
48
49-f <count>::
50--count-filter=<count>::
51 Only display functions with more events than this.
52
53--group::
54 Put the counters into a counter group.
55
56-F <freq>::
57--freq=<freq>::
58 Profile at this frequency. Use 'max' to use the currently maximum
59 allowed frequency, i.e. the value in the kernel.perf_event_max_sample_rate
60 sysctl.
61
62-i::
63--inherit::
64 Child tasks do not inherit counters.
65
66-k <path>::
67--vmlinux=<path>::
68 Path to vmlinux. Required for annotation functionality.
69
70--ignore-vmlinux::
71 Ignore vmlinux files.
72
73--kallsyms=<file>::
74 kallsyms pathname
75
76-m <pages>::
77--mmap-pages=<pages>::
78 Number of mmap data pages (must be a power of two) or size
79 specification with appended unit character - B/K/M/G. The
80 size is rounded up to have nearest pages power of two value.
81
82-p <pid>::
83--pid=<pid>::
84 Profile events on existing Process ID (comma separated list).
85
86-t <tid>::
87--tid=<tid>::
88 Profile events on existing thread ID (comma separated list).
89
90-u::
91--uid=::
92 Record events in threads owned by uid. Name or number.
93
94-r <priority>::
95--realtime=<priority>::
96 Collect data with this RT SCHED_FIFO priority.
97
98--sym-annotate=<symbol>::
99 Annotate this symbol.
100
101-K::
102--hide_kernel_symbols::
103 Hide kernel symbols.
104
105-U::
106--hide_user_symbols::
107 Hide user symbols.
108
109--demangle-kernel::
110 Demangle kernel symbols.
111
112-D::
113--dump-symtab::
114 Dump the symbol table used for profiling.
115
116-v::
117--verbose::
118 Be more verbose (show counter open errors, etc).
119
120-z::
121--zero::
122 Zero history across display updates.
123
124-s::
125--sort::
126 Sort by key(s): pid, comm, dso, symbol, parent, srcline, weight,
127 local_weight, abort, in_tx, transaction, overhead, sample, period.
128 Please see description of --sort in the perf-report man page.
129
130--fields=::
131 Specify output field - multiple keys can be specified in CSV format.
132 Following fields are available:
133 overhead, overhead_sys, overhead_us, overhead_children, sample and period.
134 Also it can contain any sort key(s).
135
136 By default, every sort keys not specified in --field will be appended
137 automatically.
138
139-n::
140--show-nr-samples::
141 Show a column with the number of samples.
142
143--show-total-period::
144 Show a column with the sum of periods.
145
146--dsos::
147 Only consider symbols in these dsos. This option will affect the
148 percentage of the overhead column. See --percentage for more info.
149
150--comms::
151 Only consider symbols in these comms. This option will affect the
152 percentage of the overhead column. See --percentage for more info.
153
154--symbols::
155 Only consider these symbols. This option will affect the
156 percentage of the overhead column. See --percentage for more info.
157
158-M::
159--disassembler-style=:: Set disassembler style for objdump.
160
161--source::
162 Interleave source code with assembly code. Enabled by default,
163 disable with --no-source.
164
165--asm-raw::
166 Show raw instruction encoding of assembly instructions.
167
168-g::
169 Enables call-graph (stack chain/backtrace) recording.
170
171--call-graph [mode,type,min[,limit],order[,key][,branch]]::
172 Setup and enable call-graph (stack chain/backtrace) recording,
173 implies -g. See `--call-graph` section in perf-record and
174 perf-report man pages for details.
175
176--children::
177 Accumulate callchain of children to parent entry so that then can
178 show up in the output. The output will have a new "Children" column
179 and will be sorted on the data. It requires -g/--call-graph option
180 enabled. See the `overhead calculation' section for more details.
181 Enabled by default, disable with --no-children.
182
183--max-stack::
184 Set the stack depth limit when parsing the callchain, anything
185 beyond the specified depth will be ignored. This is a trade-off
186 between information loss and faster processing especially for
187 workloads that can have a very long callchain stack.
188
189 Default: /proc/sys/kernel/perf_event_max_stack when present, 127 otherwise.
190
191--ignore-callees=<regex>::
192 Ignore callees of the function(s) matching the given regex.
193 This has the effect of collecting the callers of each such
194 function into one place in the call-graph tree.
195
196--percent-limit::
197 Do not show entries which have an overhead under that percent.
198 (Default: 0).
199
200--percentage::
201 Determine how to display the overhead percentage of filtered entries.
202 Filters can be applied by --comms, --dsos and/or --symbols options and
203 Zoom operations on the TUI (thread, dso, etc).
204
205 "relative" means it's relative to filtered entries only so that the
206 sum of shown entries will be always 100%. "absolute" means it retains
207 the original value before and after the filter is applied.
208
209-w::
210--column-widths=<width[,width...]>::
211 Force each column width to the provided list, for large terminal
212 readability. 0 means no limit (default behavior).
213
214--proc-map-timeout::
215 When processing pre-existing threads /proc/XXX/mmap, it may take
216 a long time, because the file may be huge. A time out is needed
217 in such cases.
218 This option sets the time out limit. The default value is 500 ms.
219
220
221-b::
222--branch-any::
223 Enable taken branch stack sampling. Any type of taken branch may be sampled.
224 This is a shortcut for --branch-filter any. See --branch-filter for more infos.
225
226-j::
227--branch-filter::
228 Enable taken branch stack sampling. Each sample captures a series of consecutive
229 taken branches. The number of branches captured with each sample depends on the
230 underlying hardware, the type of branches of interest, and the executed code.
231 It is possible to select the types of branches captured by enabling filters.
232 For a full list of modifiers please see the perf record manpage.
233
234 The option requires at least one branch type among any, any_call, any_ret, ind_call, cond.
235 The privilege levels may be omitted, in which case, the privilege levels of the associated
236 event are applied to the branch filter. Both kernel (k) and hypervisor (hv) privilege
237 levels are subject to permissions. When sampling on multiple events, branch stack sampling
238 is enabled for all the sampling events. The sampled branch type is the same for all events.
239 The various filters must be specified as a comma separated list: --branch-filter any_ret,u,k
240 Note that this feature may not be available on all processors.
241
242--raw-trace::
243 When displaying traceevent output, do not use print fmt or plugins.
244
245--hierarchy::
246 Enable hierarchy output.
247
248--overwrite::
249 Enable this to use just the most recent records, which helps in high core count
250 machines such as Knights Landing/Mill, but right now is disabled by default as
251 the pausing used in this technique is leading to loss of metadata events such
252 as PERF_RECORD_MMAP which makes 'perf top' unable to resolve samples, leading
253 to lots of unknown samples appearing on the UI. Enable this if you are in such
254 machines and profiling a workload that doesn't creates short lived threads and/or
255 doesn't uses many executable mmap operations. Work is being planed to solve
256 this situation, till then, this will remain disabled by default.
257
258--force::
259 Don't do ownership validation.
260
261--num-thread-synthesize::
262 The number of threads to run when synthesizing events for existing processes.
263 By default, the number of threads equals to the number of online CPUs.
264
265--namespaces::
266 Record events of type PERF_RECORD_NAMESPACES and display it with the
267 'cgroup_id' sort key.
268
269--switch-on EVENT_NAME::
270 Only consider events after this event is found.
271
272 E.g.:
273
274 Find out where broadcast packets are handled
275
276 perf probe -L icmp_rcv
277
278 Insert a probe there:
279
280 perf probe icmp_rcv:59
281
282 Start perf top and ask it to only consider the cycles events when a
283 broadcast packet arrives This will show a menu with two entries and
284 will start counting when a broadcast packet arrives:
285
286 perf top -e cycles,probe:icmp_rcv --switch-on=probe:icmp_rcv
287
288 Alternatively one can ask for --group and then two overhead columns
289 will appear, the first for cycles and the second for the switch-on event.
290
291 perf top --group -e cycles,probe:icmp_rcv --switch-on=probe:icmp_rcv
292
293 This may be interesting to measure a workload only after some initialization
294 phase is over, i.e. insert a perf probe at that point and use the above
295 examples replacing probe:icmp_rcv with the just-after-init probe.
296
297--switch-off EVENT_NAME::
298 Stop considering events after this event is found.
299
300--show-on-off-events::
301 Show the --switch-on/off events too. This has no effect in 'perf top' now
302 but probably we'll make the default not to show the switch-on/off events
303 on the --group mode and if there is only one event besides the off/on ones,
304 go straight to the histogram browser, just like 'perf top' with no events
305 explicitely specified does.
306
307
308INTERACTIVE PROMPTING KEYS
309--------------------------
310
311[d]::
312 Display refresh delay.
313
314[e]::
315 Number of entries to display.
316
317[E]::
318 Event to display when multiple counters are active.
319
320[f]::
321 Profile display filter (>= hit count).
322
323[F]::
324 Annotation display filter (>= % of total).
325
326[s]::
327 Annotate symbol.
328
329[S]::
330 Stop annotation, return to full profile display.
331
332[K]::
333 Hide kernel symbols.
334
335[U]::
336 Hide user symbols.
337
338[z]::
339 Toggle event count zeroing across display updates.
340
341[qQ]::
342 Quit.
343
344Pressing any unmapped key displays a menu, and prompts for input.
345
346include::callchain-overhead-calculation.txt[]
347
348SEE ALSO
349--------
350linkperf:perf-stat[1], linkperf:perf-list[1], linkperf:perf-report[1]