xref: /openbmc/linux/tools/perf/Documentation/perf-top.txt (revision ca55b2fef3a9373fcfc30f82fd26bc7fccbda732)
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]
269