linux-kernel - Re: [PATCH v1] perf lock contention: skip traceiter functions

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Message-ID: <CAM9d7chSavuxXJG8M9LMVWZfJXJPjQ3M4aLTKGsixmKef0-bkw@mail.gmail.com>
Date: Mon, 11 Mar 2024 15:29:13 -0700
From: Namhyung Kim <namhyung@...nel.org>
To: Arnaldo Carvalho de Melo <acme@...nel.org>
Cc: Anne Macedo <retpolanne@...teo.net>, Peter Zijlstra <peterz@...radead.org>, 
	Ingo Molnar <mingo@...hat.com>, Mark Rutland <mark.rutland@....com>, 
	Alexander Shishkin <alexander.shishkin@...ux.intel.com>, Jiri Olsa <jolsa@...nel.org>, 
	Ian Rogers <irogers@...gle.com>, Adrian Hunter <adrian.hunter@...el.com>, 
	linux-perf-users@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH v1] perf lock contention: skip traceiter functions

On Mon, Mar 11, 2024 at 12:53 PM Arnaldo Carvalho de Melo
<acme@...nel.org> wrote:
>
> On Mon, Mar 11, 2024 at 07:25:16PM +0000, Anne Macedo wrote:
> > Anne Macedo <retpolanne@...teo.net> writes:
> > > Namhyung Kim <namhyung@...nel.org> writes:
> > >> I think it depends on the kernel version and configuration.  I remember
> > >> I saw a different symbol on old kernels.  But it'd be hard to handle all
> > >> the cases.  Let's have a single trace text section in the struct machine
> > >> and use __traceiter_contention_begin only.  If it's not found you can
> > >> fallback to trace_contention_begin.
>
> > However, if we fallback to trace_contention_begin, we won't be able to
> > filter out both __traceiter_contention_begin and trace_contention_begin
> > at the same time.
>
> I think for ARM we need to skip both, no? I.e. I agree with Anne.

I haven't tested it on ARM, please go ahead if it is needed.

Thanks,
Namhyung