linux-kernel - [PATCHSET 0/7] perf lock: New lock contention tracepoints support (v4)

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Message-Id: <20220615163222.1275500-1-namhyung@kernel.org>
Date:   Wed, 15 Jun 2022 09:32:15 -0700
From:   Namhyung Kim <namhyung@...nel.org>
To:     Arnaldo Carvalho de Melo <acme@...nel.org>,
        Jiri Olsa <jolsa@...nel.org>
Cc:     Ingo Molnar <mingo@...nel.org>,
        Peter Zijlstra <peterz@...radead.org>,
        LKML <linux-kernel@...r.kernel.org>,
        Ian Rogers <irogers@...gle.com>,
        linux-perf-users@...r.kernel.org, Will Deacon <will@...nel.org>,
        Waiman Long <longman@...hat.com>,
        Boqun Feng <boqun.feng@...il.com>,
        Davidlohr Bueso <dave@...olabs.net>
Subject: [PATCHSET 0/7] perf lock: New lock contention tracepoints support (v4)

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