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 <command>' records lock events
between start and end <command>. 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=<file>
Input file name. (default: perf.data unless stdin is a fifo)
--output=<file>
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=<file>
vmlinux pathname
--kallsyms=<file>
kallsyms pathname
REPORT OPTIONS
-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
-t, --threads
dump thread list in perf.data
-m, --map
dump map of lock instances (address:name table)
CONTENTION OPTIONS
-k, --key=<value>
Sorting key. Possible values: contended, wait_total (default), wait_max, wait_min, avg_wait.
-F, --field=<value>
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=<value>
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=<value>
Record events on existing process ID (comma separated list).
--tid=<value>
Record events on existing thread ID (comma separated list).
-M, --map-nr-entries=<value>
Maximum number of BPF map entries (default: 16384). This will be aligned to a power of 2.
--max-stack=<value>
Maximum stack depth when collecting lock contention (default: 8).
--stack-skip=<value>
Number of stack depth to skip when finding a lock caller (default: 3).
-E, --entries=<value>
Display this many entries.
-l, --lock-addr
Show lock contention stat by address
-o, --lock-owner
Show lock contention stat by owners. Implies --threads and requires --use-bpf.
-Y, --type-filter=<value>
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, 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=<value>
Show lock contention only for given lock addresses or names (comma separated list).
-S, --callstack-filter=<value>
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=<SEP>
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=<value>
Show lock contention only in the given cgroups (comma separated list).