perf-stat(1) Run a command and gather performance counter statistics


perf stat [-e <EVENT> | --event=EVENT] [-a] <command>
perf stat [-e <EVENT> | --event=EVENT] [-a] --- <command> [<options>]


This command runs a command and gathers performance counter statistics from it.



Any command you can specify in a shell.

-e, --event=

Select the PMU event. Selection can be a symbolic event name (use perf list to list all events) or a raw PMU event (eventsel+umask) in the form of rNNN where NNN is a hexadecimal event descriptor.

-i, --no-inherit

child tasks do not inherit counters

-p, --pid=<pid>

stat events on existing process id

-t, --tid=<tid>

stat events on existing thread id

-a, --all-cpus

system-wide collection from all CPUs

-c, --scale

scale/normalize counter values

-r, --repeat=<n>

repeat command and print average + stddev (max: 100)

-B, --big-num

print large numbers with thousands' separators according to locale

-C, --cpu=

Count only on the list of CPUs provided. Multiple CPUs can be provided as a comma-separated list with no space: 0,1. Ranges of CPUs are specified with -: 0-2. In per-thread mode, this option is ignored. The -a option is still necessary to activate system-wide monitoring. Default is to count on all CPUs.

-A, --no-aggr

Do not aggregate counts across all monitored CPUs in system-wide mode (-a). This option is only valid in system-wide mode.

-n, --null

null run - don't start any counters

-v, --verbose

be more verbose (show counter open errors, etc)

-x SEP, --field-separator SEP

print counts using a CSV-style output to make it easy to import directly into spreadsheets. Columns are separated by the string specified in SEP.

-G name, --cgroup name

monitor only in the container (cgroup) called "name". This option is available only in per-cpu mode. The cgroup filesystem must be mounted. All threads belonging to container "name" are monitored when they run on the monitored CPUs. Multiple cgroups can be provided. Each cgroup is applied to the corresponding event, i.e., first cgroup to first event, second cgroup to second event and so on. It is possible to provide an empty cgroup (monitor all the time) using, e.g., -G foo,,bar. Cgroups must have corresponding events, i.e., they always refer to events defined earlier on the command line.

-o file, --output file

Print the output into the designated file.


Append to the output file designated with the -o option. Ignored if -o is not specified.


Log output to fd, instead of stderr. Complementary to --output, and mutually exclusive with it. --append may be used here. Examples: 3>results perf stat --log-fd 3 --- $cmd 3>>results perf stat --log-fd 3 --append --- $cmd


$ perf stat --- make -j

Performance counter stats for 'make -j':

8117.370256  task clock ticks     #      11.281 CPU utilization factor
        678  context switches     #       0.000 M/sec
        133  CPU migrations       #       0.000 M/sec
     235724  pagefaults           #       0.029 M/sec
24821162526  CPU cycles           #    3057.784 M/sec
18687303457  instructions         #    2302.138 M/sec
  172158895  cache references     #      21.209 M/sec
   27075259  cache misses         #       3.335 M/sec

Wall-clock time elapsed:   719.554352 msecs