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SubjectRe: [PATCHSET 0/7] perf lock: New lock contention tracepoints support (v4)
Ping!  Any comments?


On Wed, Jun 15, 2022 at 9:32 AM Namhyung Kim <namhyung@kernel.org> wrote:
>
> 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 v4)
> * add Acked-by from Ian
> * more comments on trace_lock_handler
> * don't create stats in the contention_end handler
>
> 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-v4' 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 | 426 ++++++++++++++++++++++-
> tools/perf/util/callchain.c | 18 +-
> 4 files changed, 434 insertions(+), 22 deletions(-)
>
>
> base-commit: 9886142c7a2226439c1e3f7d9b69f9c7094c3ef6
> --
> 2.36.1.476.g0c4daa206d-goog
>

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