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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
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-m <pages>::
74--mmap-pages=<pages>::
75 Number of mmap data pages (must be a power of two) or size
76 specification with appended unit character - B/K/M/G. The
77 size is rounded up to have nearest pages power of two value.
78
79-p <pid>::
80--pid=<pid>::
81 Profile events on existing Process ID (comma separated list).
82
83-t <tid>::
84--tid=<tid>::
85 Profile events on existing thread ID (comma separated list).
86
87-u::
88--uid=::
89 Record events in threads owned by uid. Name or number.
90
91-r <priority>::
92--realtime=<priority>::
93 Collect data with this RT SCHED_FIFO priority.
94
95--sym-annotate=<symbol>::
96 Annotate this symbol.
97
98-K::
99--hide_kernel_symbols::
100 Hide kernel symbols.
101
102-U::
103--hide_user_symbols::
104 Hide user symbols.
105
106--demangle-kernel::
107 Demangle kernel symbols.
108
109-D::
110--dump-symtab::
111 Dump the symbol table used for profiling.
112
113-v::
114--verbose::
115 Be more verbose (show counter open errors, etc).
116
117-z::
118--zero::
119 Zero history across display updates.
120
121-s::
122--sort::
123 Sort by key(s): pid, comm, dso, symbol, parent, srcline, weight,
124 local_weight, abort, in_tx, transaction, overhead, sample, period.
125 Please see description of --sort in the perf-report man page.
126
127--fields=::
128 Specify output field - multiple keys can be specified in CSV format.
129 Following fields are available:
130 overhead, overhead_sys, overhead_us, overhead_children, sample and period.
131 Also it can contain any sort key(s).
132
133 By default, every sort keys not specified in --field will be appended
134 automatically.
135
136-n::
137--show-nr-samples::
138 Show a column with the number of samples.
139
140--show-total-period::
141 Show a column with the sum of periods.
142
143--dsos::
144 Only consider symbols in these dsos. This option will affect the
145 percentage of the overhead column. See --percentage for more info.
146
147--comms::
148 Only consider symbols in these comms. This option will affect the
149 percentage of the overhead column. See --percentage for more info.
150
151--symbols::
152 Only consider these symbols. This option will affect the
153 percentage of the overhead column. See --percentage for more info.
154
155-M::
156--disassembler-style=:: Set disassembler style for objdump.
157
158--source::
159 Interleave source code with assembly code. Enabled by default,
160 disable with --no-source.
161
162--asm-raw::
163 Show raw instruction encoding of assembly instructions.
164
165-g::
166 Enables call-graph (stack chain/backtrace) recording.
167
168--call-graph [mode,type,min[,limit],order[,key][,branch]]::
169 Setup and enable call-graph (stack chain/backtrace) recording,
170 implies -g. See `--call-graph` section in perf-record and
171 perf-report man pages for details.
172
173--children::
174 Accumulate callchain of children to parent entry so that then can
175 show up in the output. The output will have a new "Children" column
176 and will be sorted on the data. It requires -g/--call-graph option
177 enabled. See the `overhead calculation' section for more details.
178 Enabled by default, disable with --no-children.
179
180--max-stack::
181 Set the stack depth limit when parsing the callchain, anything
182 beyond the specified depth will be ignored. This is a trade-off
183 between information loss and faster processing especially for
184 workloads that can have a very long callchain stack.
185
186 Default: /proc/sys/kernel/perf_event_max_stack when present, 127 otherwise.
187
188--ignore-callees=<regex>::
189 Ignore callees of the function(s) matching the given regex.
190 This has the effect of collecting the callers of each such
191 function into one place in the call-graph tree.
192
193--percent-limit::
194 Do not show entries which have an overhead under that percent.
195 (Default: 0).
196
197--percentage::
198 Determine how to display the overhead percentage of filtered entries.
199 Filters can be applied by --comms, --dsos and/or --symbols options and
200 Zoom operations on the TUI (thread, dso, etc).
201
202 "relative" means it's relative to filtered entries only so that the
203 sum of shown entries will be always 100%. "absolute" means it retains
204 the original value before and after the filter is applied.
205
206-w::
207--column-widths=<width[,width...]>::
208 Force each column width to the provided list, for large terminal
209 readability. 0 means no limit (default behavior).
210
211--proc-map-timeout::
212 When processing pre-existing threads /proc/XXX/mmap, it may take
213 a long time, because the file may be huge. A time out is needed
214 in such cases.
215 This option sets the time out limit. The default value is 500 ms.
216
217
218-b::
219--branch-any::
220 Enable taken branch stack sampling. Any type of taken branch may be sampled.
221 This is a shortcut for --branch-filter any. See --branch-filter for more infos.
222
223-j::
224--branch-filter::
225 Enable taken branch stack sampling. Each sample captures a series of consecutive
226 taken branches. The number of branches captured with each sample depends on the
227 underlying hardware, the type of branches of interest, and the executed code.
228 It is possible to select the types of branches captured by enabling filters.
229 For a full list of modifiers please see the perf record manpage.
230
231 The option requires at least one branch type among any, any_call, any_ret, ind_call, cond.
232 The privilege levels may be omitted, in which case, the privilege levels of the associated
233 event are applied to the branch filter. Both kernel (k) and hypervisor (hv) privilege
234 levels are subject to permissions. When sampling on multiple events, branch stack sampling
235 is enabled for all the sampling events. The sampled branch type is the same for all events.
236 The various filters must be specified as a comma separated list: --branch-filter any_ret,u,k
237 Note that this feature may not be available on all processors.
238
239--raw-trace::
240 When displaying traceevent output, do not use print fmt or plugins.
241
242--hierarchy::
243 Enable hierarchy output.
244
245--force::
246 Don't do ownership validation.
247
248--num-thread-synthesize::
249 The number of threads to run when synthesizing events for existing processes.
250 By default, the number of threads equals to the number of online CPUs.
251
252INTERACTIVE PROMPTING KEYS
253--------------------------
254
255[d]::
256 Display refresh delay.
257
258[e]::
259 Number of entries to display.
260
261[E]::
262 Event to display when multiple counters are active.
263
264[f]::
265 Profile display filter (>= hit count).
266
267[F]::
268 Annotation display filter (>= % of total).
269
270[s]::
271 Annotate symbol.
272
273[S]::
274 Stop annotation, return to full profile display.
275
276[K]::
277 Hide kernel symbols.
278
279[U]::
280 Hide user symbols.
281
282[z]::
283 Toggle event count zeroing across display updates.
284
285[qQ]::
286 Quit.
287
288Pressing any unmapped key displays a menu, and prompts for input.
289
290include::callchain-overhead-calculation.txt[]
291
292SEE ALSO
293--------
294linkperf: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]