Manual: perf-lock

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

NAME
       perf-lock - Analyze lock events

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

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

	   'perf lock record ' records lock events
	   between start and end . And this command
	   produces the file "perf.data" 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
       -i, --input=
	   Input file name. (default: perf.data unless stdin is a fifo)

       --output=
	   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=
	   vmlinux pathname

       --kallsyms=
	   kallsyms pathname

REPORT OPTIONS
       -k, --key=
	   Sorting key. Possible values: acquired (default), contended, avg_wait, wait_total, wait_max, wait_min.

       -F, --field=
	   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=
	   Display this many entries.

INFO OPTIONS
       -t, --threads
	   dump only the thread list in perf.data

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

CONTENTION OPTIONS
       -k, --key=
	   Sorting key. Possible values: contended, wait_total (default), wait_max, wait_min, avg_wait.

       -F, --field=
	   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.

       -t, --threads
	   Show per-thread lock contention stat

       -b, --use-bpf
	   Use BPF program to collect lock contention stats instead of using the input data.

       -a, --all-cpus
	   System-wide collection from all CPUs.

       -C, --cpu=
	   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.

       -p, --pid=
	   Record events on existing process ID (comma separated list).

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

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

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

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

       -E, --entries=
	   Display this many entries.

       -l, --lock-addr
	   Show lock contention stat by address

       -o, --lock-owner
	   Show lock contention stat by owners. This option can be combined with -t, which shows owner’s per thread lock
	   stats, or -v, which shows owner’s stacktrace. Requires --use-bpf.

       -Y, --type-filter=
	   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, percpu-rwmem,
	   pcpu-sem, pcpu-sem:R, pcpu-sem:W, mutex

	       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.

       -L, --lock-filter=
	   Show lock contention only for given lock addresses or names (comma separated list).

       -S, --callstack-filter=
	   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.

       -x, --field-separator=
	   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.

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

       -G, --cgroup-filter=
	   Show lock contention only in the given cgroups (comma separated list).

       -J, --inject-delay=
	   Add delays to the given lock. It’s added to the contention-end part so that the (new) owner of the lock will be
	   delayed. But by slowing down the owner, the waiters will also be delayed as well. This is working only with
	   -b/--use-bpf.

	       The 'time' is specified in nsec but it can have a unit suffix.  Available
	       units are "ms", "us" and "ns".  Currently it accepts up to 10ms of delays
	       for safety reasons.

	       Note that it will busy-wait after it gets the lock. Delaying locks can
	       have significant consequences including potential kernel crashes.  Please
	       use it at your own risk.

SEE ALSO
       perf(1)

NOTES
	1. time@function
	   mailto:time@function

perf							 07/31/2026						PERF-LOCK(1)