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- perf-stat(1)
- ============
- NAME
- ----
- perf-stat - Run a command and gather performance counter statistics
- SYNOPSIS
- --------
- [verse]
- '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)
- - a raw PMU event (eventsel+umask) in the form of rNNN where NNN is a
- hexadecimal event descriptor.
- - a symbolically formed event like 'pmu/param1=0x3,param2/' where
- param1 and param2 are defined as formats for the PMU in
- /sys/bus/event_sources/devices/<pmu>/format/*
- - a symbolically formed event like 'pmu/config=M,config1=N,config2=K/'
- where M, N, K are numbers (in decimal, hex, octal format).
- Acceptable values for each of 'config', 'config1' and 'config2'
- parameters are defined by corresponding entries in
- /sys/bus/event_sources/devices/<pmu>/format/*
- -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
- -d::
- --detailed::
- print more detailed statistics, can be specified up to 3 times
- -d: detailed events, L1 and LLC data cache
- -d -d: more detailed events, dTLB and iTLB events
- -d -d -d: very detailed events, adding prefetch events
- -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: 10ms)
- The overhead percentage could be high in some cases, for instance with small, sub 100ms intervals. Use with caution.
- 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.
- --per-thread::
- Aggregate counts per monitored threads, when monitoring threads (-t option)
- or processes (-p option).
- -D msecs::
- --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
- --------
- linkperf:perf-top[1], linkperf:perf-list[1]
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