PERF-STAT(1)							    perf Manual 						      PERF-STAT(1)

NAME

       perf-stat - Run a command and gather performance counter statistics

SYNOPSIS

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

DESCRIPTION

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

OPTIONS

       <command>...
	   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 (comma separated list)

       -t, --tid=<tid>
	   stat events on existing thread id (comma separated list)

       -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). 0 means forever.

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

       --log-fd
	   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

       --pre, --post
	   Pre and post measurement hooks, e.g.:

       perf stat --repeat 10 --null --sync --pre make -s O=defconfig-build/clean -- make -s -j64 O=defconfig-build/ bzImage

       -I msecs, --interval-print msecs
	   Print count deltas every N milliseconds (minimum: 100ms) example: perf stat -I 1000 -e cycles -a sleep 5

       --per-socket
	   Aggregate counts per processor socket for system-wide mode measurements. This is a useful mode to detect imbalance between sockets. To
	   enable this mode, use --per-socket in addition to -a. (system-wide). The output includes the socket number and the number of online
	   processors on that socket. This is useful to gauge the amount of aggregation.

       --per-core
	   Aggregate counts per physical processor for system-wide mode measurements. This is a useful mode to detect imbalance between physical
	   cores. To enable this mode, use --per-core in addition to -a. (system-wide). The output includes the core number and the number of
	   online logical processors on that physical processor.

       -D msecs, --initial-delay msecs
	   After starting the program, wait msecs before measuring. This is useful to filter out the startup phase of the program, which is often
	   very different.

       -T, --transaction
	   Print statistics of transactional execution if supported.

EXAMPLES

       $ 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

SEE ALSO

       perf-top(1), perf-list(1)

perf								    06/30/2014							      PERF-STAT(1)