linux-kernel - Re: [PATCH] perf lock: Allow concurrent record and report

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Message-ID: <Y21ETduUDa86eib6@kernel.org>
Date:   Thu, 10 Nov 2022 15:34:53 -0300
From:   Arnaldo Carvalho de Melo <acme@...nel.org>
To:     Ian Rogers <irogers@...gle.com>
Cc:     Namhyung Kim <namhyung@...nel.org>, Jiri Olsa <jolsa@...nel.org>,
        Ingo Molnar <mingo@...nel.org>,
        Peter Zijlstra <peterz@...radead.org>,
        LKML <linux-kernel@...r.kernel.org>,
        Adrian Hunter <adrian.hunter@...el.com>,
        linux-perf-users@...r.kernel.org
Subject: Re: [PATCH] perf lock: Allow concurrent record and report

Em Tue, Nov 08, 2022 at 03:26:01PM -0800, Ian Rogers escreveu:
> On Thu, Nov 3, 2022 at 10:14 PM Namhyung Kim <namhyung@...nel.org> wrote:
> >
> > To support live monitoring of kernel lock contention without BPF,
> > it should support something like below:
> >
> >   # perf lock record -a -o- sleep 1 | perf lock contention -i-
> >    contended   total wait     max wait     avg wait         type   caller
> >
> >            2     10.27 us      6.17 us      5.13 us     spinlock   load_balance+0xc03
> >            1      5.29 us      5.29 us      5.29 us     rwlock:W   ep_scan_ready_list+0x54
> >            1      4.12 us      4.12 us      4.12 us     spinlock   smpboot_thread_fn+0x116
> >            1      3.28 us      3.28 us      3.28 us        mutex   pipe_read+0x50
> >
> > To do that, it needs to handle HEAD_ATTR, HEADER_EVENT_UPDATE and
> > HEADER_TRACING_DATA which are generated only for the pipe mode.
> > And setting event handler also should be delayed until it gets the
> > event information.
> >
> > Signed-off-by: Namhyung Kim <namhyung@...nel.org>
> 
> Acked-by: Ian Rogers <irogers@...gle.com>

Thanks, applied.

- Arnaldo