From: Ingo Molnar <mingo@kernel.org>
To: Namhyung Kim <namhyung@kernel.org>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>,
Jiri Olsa <jolsa@kernel.org>,
Peter Zijlstra <peterz@infradead.org>,
LKML <linux-kernel@vger.kernel.org>,
Ian Rogers <irogers@google.com>,
linux-perf-users@vger.kernel.org, Will Deacon <will@kernel.org>,
Waiman Long <longman@redhat.com>,
Boqun Feng <boqun.feng@gmail.com>,
Davidlohr Bueso <dave@stgolabs.net>
Subject: Re: [PATCHSET 0/6] perf lock: Add contention subcommand (v1)
Date: Wed, 3 Aug 2022 11:51:14 +0200 [thread overview]
Message-ID: <YupFEkzCDxpFUyeD@gmail.com> (raw)
In-Reply-To: <20220721043644.153718-1-namhyung@kernel.org>
* Namhyung Kim <namhyung@kernel.org> wrote:
> Hello,
>
> It's to add a new subcommand 'contention' (shortly 'con') to perf lock.
>
> 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
> ...
Wouldn't it also be useful to display a lock contention percentage value,
the ratio of fastpath vs. contended/wait events?
That's usually the first-approximation metric to see how contended
different locks are, and the average wait time quantifies it.
Thanks,
Ingo
next prev parent reply other threads:[~2022-08-03 9:52 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-07-21 4:36 [PATCHSET 0/6] perf lock: Add contention subcommand (v1) Namhyung Kim
2022-07-21 4:36 ` [PATCH 1/6] perf lock: Fix a copy-n-paste bug Namhyung Kim
2022-07-21 19:09 ` Arnaldo Carvalho de Melo
2022-07-21 4:36 ` [PATCH 2/6] perf lock: Add flags field in the lock_stat Namhyung Kim
2022-07-21 4:36 ` [PATCH 3/6] perf lock: Add lock aggregation enum Namhyung Kim
2022-07-21 19:02 ` Arnaldo Carvalho de Melo
2022-07-21 19:05 ` Arnaldo Carvalho de Melo
2022-07-25 16:56 ` Namhyung Kim
2022-07-21 4:36 ` [PATCH 4/6] perf lock: Add 'contention' subcommand Namhyung Kim
2022-07-21 4:36 ` [PATCH 5/6] perf lock: Add -k and -F options to " Namhyung Kim
2022-07-21 4:36 ` [PATCH 6/6] perf lock: Support -t option for " Namhyung Kim
2022-08-03 9:51 ` Ingo Molnar [this message]
2022-08-04 4:55 ` [PATCHSET 0/6] perf lock: Add contention subcommand (v1) Namhyung Kim
2022-08-04 8:37 ` Ingo Molnar
2022-08-04 21:02 ` Namhyung Kim
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