linux-kernel - [PATCHSET 0/5] perf lock: Add contention subcommand (v2)

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Date:   Mon, 25 Jul 2022 11:31:19 -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 0/5] perf lock: Add contention subcommand (v2)

Hello,

It's to add a new subcommand 'contention' (shortly 'con') to perf lock.

Changes in v2)
* bugfix is merged already
* fix build error in patch 2

The new subcommand is to handle the new lock:contention_{begin,end}
tracepoints and shows lock type and caller address like below:

  $ perf lock contention
   contended   total wait     max wait     avg wait         type   caller

         238      1.41 ms     29.20 us      5.94 us     spinlock   update_blocked_averages+0x4c
           1    902.08 us    902.08 us    902.08 us      rwsem:R   do_user_addr_fault+0x1dd
          81    330.30 us     17.24 us      4.08 us     spinlock   _nohz_idle_balance+0x172
           2     89.54 us     61.26 us     44.77 us     spinlock   do_anonymous_page+0x16d
          24     78.36 us     12.27 us      3.27 us        mutex   pipe_read+0x56
           2     71.58 us     59.56 us     35.79 us     spinlock   __handle_mm_fault+0x6aa
           6     25.68 us      6.89 us      4.28 us     spinlock   do_idle+0x28d
           1     18.46 us     18.46 us     18.46 us      rtmutex   exec_fw_cmd+0x21b
           3     15.25 us      6.26 us      5.08 us     spinlock   tick_do_update_jiffies64+0x2c
   ...

where rwsem:R stands for read access (down_read) for a rw-semaphore.
Other types of lock access is obvious and it doesn't detect optimistic
spinning on mutex yet.  This is just a base work for lock contention
analysis and more will come later.

You can get this from 'perf/lock-subcmd-v2' branch on

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

Thanks,
Namhyung


Namhyung Kim (5):
  perf lock: Add flags field in the lock_stat
  perf lock: Add lock aggregation enum
  perf lock: Add 'contention' subcommand
  perf lock: Add -k and -F options to 'contention' subcommand
  perf lock: Support -t option for 'contention' subcommand

 tools/perf/Documentation/perf-lock.txt |  23 +-
 tools/perf/builtin-lock.c              | 401 +++++++++++++++++++++++--
 2 files changed, 390 insertions(+), 34 deletions(-)


base-commit: 9fe9b252c7c022df8e503435e778f15c04dfa3bf
-- 
2.37.1.359.gd136c6c3e2-goog