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linux
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.
59
60-i::
61--inherit::
62 Child tasks do not inherit counters.
63
64-k <path>::
65--vmlinux=<path>::
66 Path to vmlinux. Required for annotation functionality.
67
68-m <pages>::
69--mmap-pages=<pages>::
70 Number of mmap data pages (must be a power of two) or size
71 specification with appended unit character - B/K/M/G. The
72 size is rounded up to have nearest pages power of two value.
73
74-p <pid>::
75--pid=<pid>::
76 Profile events on existing Process ID (comma separated list).
77
78-t <tid>::
79--tid=<tid>::
80 Profile events on existing thread ID (comma separated list).
81
82-u::
83--uid=::
84 Record events in threads owned by uid. Name or number.
85
86-r <priority>::
87--realtime=<priority>::
88 Collect data with this RT SCHED_FIFO priority.
89
90--sym-annotate=<symbol>::
91 Annotate this symbol.
92
93-K::
94--hide_kernel_symbols::
95 Hide kernel symbols.
96
97-U::
98--hide_user_symbols::
99 Hide user symbols.
100
101--demangle-kernel::
102 Demangle kernel symbols.
103
104-D::
105--dump-symtab::
106 Dump the symbol table used for profiling.
107
108-v::
109--verbose::
110 Be more verbose (show counter open errors, etc).
111
112-z::
113--zero::
114 Zero history across display updates.
115
116-s::
117--sort::
118 Sort by key(s): pid, comm, dso, symbol, parent, srcline, weight,
119 local_weight, abort, in_tx, transaction, overhead, sample, period.
120 Please see description of --sort in the perf-report man page.
121
122--fields=::
123 Specify output field - multiple keys can be specified in CSV format.
124 Following fields are available:
125 overhead, overhead_sys, overhead_us, overhead_children, sample and period.
126 Also it can contain any sort key(s).
127
128 By default, every sort keys not specified in --field will be appended
129 automatically.
130
131-n::
132--show-nr-samples::
133 Show a column with the number of samples.
134
135--show-total-period::
136 Show a column with the sum of periods.
137
138--dsos::
139 Only consider symbols in these dsos. This option will affect the
140 percentage of the overhead column. See --percentage for more info.
141
142--comms::
143 Only consider symbols in these comms. This option will affect the
144 percentage of the overhead column. See --percentage for more info.
145
146--symbols::
147 Only consider these symbols. This option will affect the
148 percentage of the overhead column. See --percentage for more info.
149
150-M::
151--disassembler-style=:: Set disassembler style for objdump.
152
153--source::
154 Interleave source code with assembly code. Enabled by default,
155 disable with --no-source.
156
157--asm-raw::
158 Show raw instruction encoding of assembly instructions.
159
160-g::
161 Enables call-graph (stack chain/backtrace) recording.
162
163--call-graph::
164 Setup and enable call-graph (stack chain/backtrace) recording,
165 implies -g.
166
167--children::
168 Accumulate callchain of children to parent entry so that then can
169 show up in the output. The output will have a new "Children" column
170 and will be sorted on the data. It requires -g/--call-graph option
171 enabled. See the `overhead calculation' section for more details.
172
173--max-stack::
174 Set the stack depth limit when parsing the callchain, anything
175 beyond the specified depth will be ignored. This is a trade-off
176 between information loss and faster processing especially for
177 workloads that can have a very long callchain stack.
178
179 Default: 127
180
181--ignore-callees=<regex>::
182 Ignore callees of the function(s) matching the given regex.
183 This has the effect of collecting the callers of each such
184 function into one place in the call-graph tree.
185
186--percent-limit::
187 Do not show entries which have an overhead under that percent.
188 (Default: 0).
189
190--percentage::
191 Determine how to display the overhead percentage of filtered entries.
192 Filters can be applied by --comms, --dsos and/or --symbols options and
193 Zoom operations on the TUI (thread, dso, etc).
194
195 "relative" means it's relative to filtered entries only so that the
196 sum of shown entries will be always 100%. "absolute" means it retains
197 the original value before and after the filter is applied.
198
199-w::
200--column-widths=<width[,width...]>::
201 Force each column width to the provided list, for large terminal
202 readability. 0 means no limit (default behavior).
203
204--proc-map-timeout::
205 When processing pre-existing threads /proc/XXX/mmap, it may take
206 a long time, because the file may be huge. A time out is needed
207 in such cases.
208 This option sets the time out limit. The default value is 500 ms.
209
210
211-b::
212--branch-any::
213 Enable taken branch stack sampling. Any type of taken branch may be sampled.
214 This is a shortcut for --branch-filter any. See --branch-filter for more infos.
215
216-j::
217--branch-filter::
218 Enable taken branch stack sampling. Each sample captures a series of consecutive
219 taken branches. The number of branches captured with each sample depends on the
220 underlying hardware, the type of branches of interest, and the executed code.
221 It is possible to select the types of branches captured by enabling filters.
222 For a full list of modifiers please see the perf record manpage.
223
224 The option requires at least one branch type among any, any_call, any_ret, ind_call, cond.
225 The privilege levels may be omitted, in which case, the privilege levels of the associated
226 event are applied to the branch filter. Both kernel (k) and hypervisor (hv) privilege
227 levels are subject to permissions. When sampling on multiple events, branch stack sampling
228 is enabled for all the sampling events. The sampled branch type is the same for all events.
229 The various filters must be specified as a comma separated list: --branch-filter any_ret,u,k
230 Note that this feature may not be available on all processors.
231
232INTERACTIVE PROMPTING KEYS
233--------------------------
234
235[d]::
236 Display refresh delay.
237
238[e]::
239 Number of entries to display.
240
241[E]::
242 Event to display when multiple counters are active.
243
244[f]::
245 Profile display filter (>= hit count).
246
247[F]::
248 Annotation display filter (>= % of total).
249
250[s]::
251 Annotate symbol.
252
253[S]::
254 Stop annotation, return to full profile display.
255
256[z]::
257 Toggle event count zeroing across display updates.
258
259[qQ]::
260 Quit.
261
262Pressing any unmapped key displays a menu, and prompts for input.
263
264include::callchain-overhead-calculation.txt[]
265
266SEE ALSO
267--------
268linkperf:perf-stat[1], linkperf:perf-list[1], linkperf:perf-report[1]