perf-lock(1) — Linux manual page


PERF-LOCK(1)                   perf Manual                  PERF-LOCK(1)

NAME         top

       perf-lock - Analyze lock events

SYNOPSIS         top

       perf lock {record|report|script|info|contention}

DESCRIPTION         top

       You can analyze various lock behaviours and statistics with this
       perf lock command.

           'perf lock record <command>' records lock events
           between start and end <command>. And this command
           produces the file "" which contains tracing
           results of lock events.

           'perf lock report' reports statistical data.

           'perf lock script' shows raw lock events.

           'perf lock info' shows metadata like threads or addresses
           of lock instances.

           'perf lock contention' shows contention statistics.

COMMON OPTIONS         top

       -i, --input=<file>
           Input file name. (default: unless stdin is a fifo)

           Output file name for perf lock contention and report.

       -v, --verbose
           Be more verbose (show symbol address, etc).

       -q, --quiet
           Do not show any warnings or messages. (Suppress -v)

       -D, --dump-raw-trace
           Dump raw trace in ASCII.

       -f, --force
           Don’t complain, do it.

           vmlinux pathname

           kallsyms pathname

REPORT OPTIONS         top

       -k, --key=<value>
           Sorting key. Possible values: acquired (default), contended,
           avg_wait, wait_total, wait_max, wait_min.

       -F, --field=<value>
           Output fields. By default it shows all the fields but users
           can customize that using this. Possible values: acquired,
           contended, avg_wait, wait_total, wait_max, wait_min.

       -c, --combine-locks
           Merge lock instances in the same class (based on name).

       -t, --threads
           The -t option is to show per-thread lock stat like below:

               $ perf lock report -t -F acquired,contended,avg_wait

               Name   acquired  contended   avg wait (ns)

                          perf     240569          9            5784
                       swapper     106610         19             543
                        :15789      17370          2           14538
                  ContainerMgr       8981          6             874
                         sleep       5275          1           11281
               ContainerThread       4416          4             944
               RootPressureThr       3215          5            1215
                   rcu_preempt       2954          0               0
                  ContainerMgr       2560          0               0
                       unnamed       1873          0               0
               EventManager_De       1845          1             636
               futex-default-S       1609          0               0

       -E, --entries=<value>
           Display this many entries.

INFO OPTIONS         top

       -t, --threads
           dump thread list in

       -m, --map
           dump map of lock instances (address:name table)


           .ft C
                   Sorting key. Possible values: contended, wait_total (default),
                   wait_max, wait_min, avg_wait.

                   Output fields. By default it shows all but the wait_min fields
                   and users can customize that using this.  Possible values:
                   contended, wait_total, wait_max, wait_min, avg_wait.

                   Show per-thread lock contention stat

                   Use BPF program to collect lock contention stats instead of
                   using the input data.

                   System-wide collection from all CPUs.

                   Collect samples 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.  Default is to monitor all CPUs.

                   Record events on existing process ID (comma separated list).

                   Record events on existing thread ID (comma separated list).

                   Maximum number of BPF map entries (default: 16384).
                   This will be aligned to a power of 2.

                   Maximum stack depth when collecting lock contention (default: 8).

                   Number of stack depth to skip when finding a lock caller (default: 3).

                   Display this many entries.

                   Show lock contention stat by address

                   Show lock contention stat by owners.  Implies --threads and
                   requires --use-bpf.

                   Show lock contention only for given lock types (comma separated list).
                   Available values are:
                     semaphore, spinlock, rwlock, rwlock:R, rwlock:W, rwsem, rwsem:R, rwsem:W,
                     rtmutex, rwlock-rt, rwlock-rt:R, rwlock-rt:W, pcpu-sem, pcpu-sem:R, pcpu-sem:W,

                   Note that RW-variant of locks have :R and :W suffix.  Names without the
                   suffix are shortcuts for the both variants.  Ex) rwsem = rwsem:R + rwsem:W.

                   Show lock contention only for given lock addresses or names (comma separated list).

                   Show lock contention only if the callstack contains the given string.
                   Note that it matches the substring so 'rq' would match both 'raw_spin_rq_lock'
                   and 'irq_enter_rcu'.

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

                   Show lock contention stat by cgroup.  Requires --use-bpf.

                   Show lock contention only in the given cgroups (comma separated list).

           SEE ALSO


COLOPHON         top

       This page is part of the perf (Performance analysis tools for
       Linux (in Linux source tree)) project.  Information about the
       project can be found at 
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       bug report for this manual page, send it to  This page was obtained from the
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       on 2023-12-22.  (At that time, the date of the most recent commit
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perf                           2023-09-12                   PERF-LOCK(1)

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