From: Arnaldo Carvalho de Melo <acme@kernel.org>
To: Namhyung Kim <namhyung@kernel.org>
Cc: Ian Rogers <irogers@google.com>,
Kan Liang <kan.liang@linux.intel.com>,
Jiri Olsa <jolsa@kernel.org>,
Adrian Hunter <adrian.hunter@intel.com>,
Peter Zijlstra <peterz@infradead.org>,
Ingo Molnar <mingo@kernel.org>,
LKML <linux-kernel@vger.kernel.org>,
linux-perf-users@vger.kernel.org, Song Liu <song@kernel.org>,
bpf@vger.kernel.org, Xi Wang <xii@google.com>
Subject: Re: [PATCH] perf lock contention: Fix spinlock and rwlock accounting
Date: Fri, 30 Aug 2024 10:23:52 -0300 [thread overview]
Message-ID: <ZtHH6JcfNUBAQAen@x1> (raw)
In-Reply-To: <20240828052953.1445862-1-namhyung@kernel.org>
On Tue, Aug 27, 2024 at 10:29:53PM -0700, Namhyung Kim wrote:
> The spinlock and rwlock use a single-element per-cpu array to track
> current locks due to performance reason. But this means the key is
> always available and it cannot simply account lock stats in the array
> because some of them are invalid.
>
> In fact, the contention_end() program in the BPF invalidates the entry
> by setting the 'lock' value to 0 instead of deleting the entry for the
> hashmap. So it should skip entries with the lock value of 0 in the
> account_end_timestamp().
Thanks, applied to perf-tools-next,
- Arnaldo
next prev parent reply other threads:[~2024-08-30 13:23 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-08-28 5:29 [PATCH] perf lock contention: Fix spinlock and rwlock accounting Namhyung Kim
2024-08-30 13:23 ` Arnaldo Carvalho de Melo [this message]
[not found] ` <CAM9d7ch27q8JycAvOqKzeG+0eXFbJ_o6qZoVSS6aUrWTpU=vdQ@mail.gmail.com>
2024-08-30 20:47 ` Arnaldo Carvalho de Melo
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