1perf-stat(1)
2============
3
4NAME
5----
6perf-stat - Run a command and gather performance counter statistics
7
8SYNOPSIS
9--------
10[verse]
11'perf stat' [-e <EVENT> | --event=EVENT] [-a] <command>
12'perf stat' [-e <EVENT> | --event=EVENT] [-a] -- <command> [<options>]
13
14DESCRIPTION
15-----------
16This command runs a command and gathers performance counter statistics
17from it.
18
19
20OPTIONS
21-------
22<command>...::
23	Any command you can specify in a shell.
24
25
26-e::
27--event=::
28	Select the PMU event. Selection can be:
29
30	- a symbolic event name (use 'perf list' to list all events)
31
32	- a raw PMU event (eventsel+umask) in the form of rNNN where NNN is a
33	  hexadecimal event descriptor.
34
35	- a symbolically formed event like 'pmu/param1=0x3,param2/' where
36	  param1 and param2 are defined as formats for the PMU in
37	  /sys/bus/event_sources/devices/<pmu>/format/*
38
39	- a symbolically formed event like 'pmu/config=M,config1=N,config2=K/'
40	  where M, N, K are numbers (in decimal, hex, octal format).
41	  Acceptable values for each of 'config', 'config1' and 'config2'
42	  parameters are defined by corresponding entries in
43	  /sys/bus/event_sources/devices/<pmu>/format/*
44
45-i::
46--no-inherit::
47        child tasks do not inherit counters
48-p::
49--pid=<pid>::
50        stat events on existing process id (comma separated list)
51
52-t::
53--tid=<tid>::
54        stat events on existing thread id (comma separated list)
55
56
57-a::
58--all-cpus::
59        system-wide collection from all CPUs
60
61-c::
62--scale::
63	scale/normalize counter values
64
65-r::
66--repeat=<n>::
67	repeat command and print average + stddev (max: 100). 0 means forever.
68
69-B::
70--big-num::
71        print large numbers with thousands' separators according to locale
72
73-C::
74--cpu=::
75Count only on the list of CPUs provided. Multiple CPUs can be provided as a
76comma-separated list with no space: 0,1. Ranges of CPUs are specified with -: 0-2.
77In per-thread mode, this option is ignored. The -a option is still necessary
78to activate system-wide monitoring. Default is to count on all CPUs.
79
80-A::
81--no-aggr::
82Do not aggregate counts across all monitored CPUs in system-wide mode (-a).
83This option is only valid in system-wide mode.
84
85-n::
86--null::
87        null run - don't start any counters
88
89-v::
90--verbose::
91        be more verbose (show counter open errors, etc)
92
93-x SEP::
94--field-separator SEP::
95print counts using a CSV-style output to make it easy to import directly into
96spreadsheets. Columns are separated by the string specified in SEP.
97
98-G name::
99--cgroup name::
100monitor only in the container (cgroup) called "name". This option is available only
101in per-cpu mode. The cgroup filesystem must be mounted. All threads belonging to
102container "name" are monitored when they run on the monitored CPUs. Multiple cgroups
103can be provided. Each cgroup is applied to the corresponding event, i.e., first cgroup
104to first event, second cgroup to second event and so on. It is possible to provide
105an empty cgroup (monitor all the time) using, e.g., -G foo,,bar. Cgroups must have
106corresponding events, i.e., they always refer to events defined earlier on the command
107line.
108
109-o file::
110--output file::
111Print the output into the designated file.
112
113--append::
114Append to the output file designated with the -o option. Ignored if -o is not specified.
115
116--log-fd::
117
118Log output to fd, instead of stderr.  Complementary to --output, and mutually exclusive
119with it.  --append may be used here.  Examples:
120     3>results  perf stat --log-fd 3          -- $cmd
121     3>>results perf stat --log-fd 3 --append -- $cmd
122
123--pre::
124--post::
125	Pre and post measurement hooks, e.g.:
126
127perf stat --repeat 10 --null --sync --pre 'make -s O=defconfig-build/clean' -- make -s -j64 O=defconfig-build/ bzImage
128
129-I msecs::
130--interval-print msecs::
131Print count deltas every N milliseconds (minimum: 10ms)
132The overhead percentage could be high in some cases, for instance with small, sub 100ms intervals.  Use with caution.
133	example: 'perf stat -I 1000 -e cycles -a sleep 5'
134
135--per-socket::
136Aggregate counts per processor socket for system-wide mode measurements.  This
137is a useful mode to detect imbalance between sockets.  To enable this mode,
138use --per-socket in addition to -a. (system-wide).  The output includes the
139socket number and the number of online processors on that socket. This is
140useful to gauge the amount of aggregation.
141
142--per-core::
143Aggregate counts per physical processor for system-wide mode measurements.  This
144is a useful mode to detect imbalance between physical cores.  To enable this mode,
145use --per-core in addition to -a. (system-wide).  The output includes the
146core number and the number of online logical processors on that physical processor.
147
148--per-thread::
149Aggregate counts per monitored threads, when monitoring threads (-t option)
150or processes (-p option).
151
152-D msecs::
153--delay msecs::
154After starting the program, wait msecs before measuring. This is useful to
155filter out the startup phase of the program, which is often very different.
156
157-T::
158--transaction::
159
160Print statistics of transactional execution if supported.
161
162EXAMPLES
163--------
164
165$ perf stat -- make -j
166
167 Performance counter stats for 'make -j':
168
169    8117.370256  task clock ticks     #      11.281 CPU utilization factor
170            678  context switches     #       0.000 M/sec
171            133  CPU migrations       #       0.000 M/sec
172         235724  pagefaults           #       0.029 M/sec
173    24821162526  CPU cycles           #    3057.784 M/sec
174    18687303457  instructions         #    2302.138 M/sec
175      172158895  cache references     #      21.209 M/sec
176       27075259  cache misses         #       3.335 M/sec
177
178 Wall-clock time elapsed:   719.554352 msecs
179
180SEE ALSO
181--------
182linkperf:perf-top[1], linkperf:perf-list[1]
183