linux-kernel - Re: [PATCH v1] perf test: Fix hybrid testing of event fallback test

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Message-ID: <CAP-5=fX8MgFXtYtxtYpDsVb5SHjxELPCRNcySJcNVEtC1pOieA@mail.gmail.com>
Date: Tue, 2 Dec 2025 15:05:12 -0800
From: Ian Rogers <irogers@...gle.com>
To: Namhyung Kim <namhyung@...nel.org>
Cc: Peter Zijlstra <peterz@...radead.org>, Ingo Molnar <mingo@...hat.com>, 
	Arnaldo Carvalho de Melo <acme@...nel.org>, Alexander Shishkin <alexander.shishkin@...ux.intel.com>, 
	Jiri Olsa <jolsa@...nel.org>, Adrian Hunter <adrian.hunter@...el.com>, 
	Zide Chen <zide.chen@...el.com>, Dapeng Mi <dapeng1.mi@...ux.intel.com>, 
	linux-perf-users@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH v1] perf test: Fix hybrid testing of event fallback test

On Tue, Dec 2, 2025 at 1:41 PM Namhyung Kim <namhyung@...nel.org> wrote:
>
> On Mon, Dec 01, 2025 at 03:11:36PM -0800, Ian Rogers wrote:
> > The mem-loads-aux event exists on hybrid systems but the "cpu" PMU
> > does not. This causes an event parsing error which erroneously makes
> > the test look like it is failing. Avoid naming the PMU to avoid
> > this. Rather than cleaning up perf.data in the directory the test is
> > run, explicitly send the 'perf record' output to /dev/null and avoid
> > any cleanup scripts.
> >
> > Fixes: fc9c17b22352 ("perf test: Add a perf event fallback test")
> > Signed-off-by: Ian Rogers <irogers@...gle.com>
> > ---
> >  .../tests/shell/test_event_open_fallback.sh   | 19 ++-----------------
> >  1 file changed, 2 insertions(+), 17 deletions(-)
> >
> > diff --git a/tools/perf/tests/shell/test_event_open_fallback.sh b/tools/perf/tests/shell/test_event_open_fallback.sh
> > index 9c411153c01b..9420a7557c13 100755
> > --- a/tools/perf/tests/shell/test_event_open_fallback.sh
> > +++ b/tools/perf/tests/shell/test_event_open_fallback.sh
> > @@ -6,24 +6,9 @@ skip_cnt=0
> >  ok_cnt=0
> >  err_cnt=0
> >
> > -cleanup()
> > -{
> > -     rm -f perf.data
> > -     rm -f perf.data.old
> > -     trap - EXIT TERM INT
> > -}
> > -
> > -trap_cleanup()
> > -{
> > -     cleanup
> > -     exit 1
> > -}
> > -
> > -trap trap_cleanup EXIT TERM INT
> > -
> >  perf_record()
> >  {
> > -     perf record "$@" -- true 1>/dev/null 2>&1
> > +     perf record -o /dev/null "$@" -- true 1>/dev/null 2>&1
> >  }
> >
> >  test_decrease_precise_ip()
> > @@ -49,7 +34,7 @@ test_decrease_precise_ip_complicated()
> >
> >       perf list pmu | grep -q 'mem-loads-aux' || return 2
> >
> > -     if ! perf_record -e '{cpu/mem-loads-aux/S,cpu/mem-loads/PS}'; then
> > +     if ! perf_record -e '{mem-loads-aux:S,mem-loads:PS}'; then
>
> I think we need to either keep the trap handler or convert all perf
> record commands including this to use -o /dev/null.

So all the perf record commands use "-o /dev/null" as perf record is
always run using the "perf_record" function (ie the one updated here)
:-)

Thanks,
Ian

> Thanks,
> Namhyung
>
>
> >               return 1
> >       fi
> >       return 0
> > --
> > 2.52.0.158.g65b55ccf14-goog
> >