lkml.org 
[lkml]   [2022]   [Jun]   [9]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
From
Subject[PATCHSET 0/7] perf lock: New lock contention tracepoints support (v3)
Date
Hello,

Kernel v5.19 will have a new set of tracepoints to track lock
contentions for various lock types. Unlike tracepoints in LOCKDEP and
LOCK_STAT, it's hit only for contended locks and lock names are not
available. So it needs to collect stack traces and display the caller
function instead.

Changes in v3)
* fix build error
* support data from different kernels/machines
* skip bad stat unless there's actual bad ones

Changes in v2)
* add Acked-by from Ian
* print time with a unit for compact output
* add some comments (Ian)
* remove already applied patch

This patchset merely adds support for the new tracepoints to the
existing perf lock commands. So there's no change to the user. Later
I'll add new a sub-command dedicated to the tracepoints to make use of
the additional information.

Example output:

$ sudo perf lock record -a sleep 3

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

Name acquired contended avg wait total wait

update_blocked_a... 40 40 3.61 us 144.45 us
kernfs_fop_open+... 5 5 3.64 us 18.18 us
_nohz_idle_balance 3 3 2.65 us 7.95 us
tick_do_update_j... 1 1 6.04 us 6.04 us
ep_scan_ready_list 1 1 3.93 us 3.93 us
...

You can find the code in the 'perf/lock-contention-v3' branch at

git://git.kernel.org/pub/scm/linux/kernel/git/namhyung/linux-perf.git

Thanks,
Namhyung


Namhyung Kim (7):
perf lock: Print wait times with unit
perf lock: Allow to use different kernel symbols
perf lock: Skip print_bad_events() if nothing bad
perf lock: Add lock contention tracepoints record support
perf lock: Handle lock contention tracepoints
perf record: Allow to specify max stack depth of fp callchain
perf lock: Look up callchain for the contended locks

tools/perf/Documentation/perf-lock.txt | 7 +
tools/perf/Documentation/perf-record.txt | 5 +
tools/perf/builtin-lock.c | 424 ++++++++++++++++++++++-
tools/perf/util/callchain.c | 18 +-
4 files changed, 432 insertions(+), 22 deletions(-)


base-commit: 9886142c7a2226439c1e3f7d9b69f9c7094c3ef6
--
2.36.1.255.ge46751e96f-goog

\
 
 \ /
  Last update: 2022-06-09 07:58    [W:0.039 / U:0.072 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site