linux-kernel - Re: [PATCH v1] perf test: Ignore security failures in all PMU test

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Message-ID: <CAP-5=fXJ-Nd-8EUPD+JXy=chZX_7nFYMxRR5L_ovn83+Tt1f_g@mail.gmail.com>
Date: Thu, 26 Sep 2024 08:24:30 -0700
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>, Mark Rutland <mark.rutland@....com>, 
	Alexander Shishkin <alexander.shishkin@...ux.intel.com>, Jiri Olsa <jolsa@...nel.org>, 
	Adrian Hunter <adrian.hunter@...el.com>, Kan Liang <kan.liang@...ux.intel.com>, 
	Colin Ian King <colin.i.king@...il.com>, Athira Jajeev <atrajeev@...ux.vnet.ibm.com>, 
	linux-perf-users@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH v1] perf test: Ignore security failures in all PMU test

On Wed, Sep 25, 2024 at 9:52 PM Namhyung Kim <namhyung@...nel.org> wrote:
>
> On Wed, Sep 25, 2024 at 10:30:13AM -0700, Ian Rogers wrote:
> > Refactor code to have some more error diagnosis on traps, etc. and to
> > do less work on each line. Add an ignore situation for security failures.
> >
> > Signed-off-by: Ian Rogers <irogers@...gle.com>
> > ---
> >  tools/perf/tests/shell/stat_all_pmu.sh | 52 ++++++++++++++++++++------
> >  1 file changed, 40 insertions(+), 12 deletions(-)
> >
> > diff --git a/tools/perf/tests/shell/stat_all_pmu.sh b/tools/perf/tests/shell/stat_all_pmu.sh
> > index d2a3506e0d19..42456d89c5da 100755
> > --- a/tools/perf/tests/shell/stat_all_pmu.sh
> > +++ b/tools/perf/tests/shell/stat_all_pmu.sh
> > @@ -1,23 +1,51 @@
> > -#!/bin/sh
> > +#!/bin/bash
> >  # perf all PMU test
> >  # SPDX-License-Identifier: GPL-2.0
> >
> >  set -e
> > +err=0
> > +result=""
> > +
> > +trap_cleanup() {
> > +  echo "Unexpected signal in ${FUNCNAME[1]}"
> > +  echo "$result"
> > +  exit 1
> > +}
> > +trap trap_cleanup EXIT TERM INT
> >
> >  # Test all PMU events; however exclude parameterized ones (name contains '?')
> > -for p in $(perf list --raw-dump pmu | sed 's/[[:graph:]]\+?[[:graph:]]\+[[:space:]]//g'); do
> > +for p in $(perf list --raw-dump pmu | sed 's/[[:graph:]]\+?[[:graph:]]\+[[:space:]]//g')
> > +do
> >    echo "Testing $p"
> >    result=$(perf stat -e "$p" true 2>&1)
> > -  if ! echo "$result" | grep -q "$p" && ! echo "$result" | grep -q "<not supported>" ; then
> > -    # We failed to see the event and it is supported. Possibly the workload was
> > -    # too small so retry with something longer.
> > -    result=$(perf stat -e "$p" perf bench internals synthesize 2>&1)
> > -    if ! echo "$result" | grep -q "$p" ; then
> > -      echo "Event '$p' not printed in:"
> > -      echo "$result"
> > -      exit 1
> > -    fi
> > +  if echo "$result" | grep -q "$p"
> > +  then
> > +    # Event seen in output.
> > +    continue
> > +  fi
> > +  if echo "$result" | grep -q "<not supported>"
> > +  then
> > +    # Event not supported, so ignore.
> > +    continue
>
> I'm curious about this case.  It'll show up even if it's not supported
> right?  Then the first condition would match and it doesn't reach here.
>
>   $ perf stat -e LLC-loads true
>
>    Performance counter stats for 'true':
>
>      <not supported>      LLC-loads
>
>          0.001213558 seconds time elapsed
>
>          0.001373000 seconds user
>          0.000000000 seconds sys

We carry this change at Google for an issue on older series kernels. I
was resending the patch as a courtesy in the migration of development
work to:
https://github.com/googleprodkernel/linux-perf
I'm okay with this being a Google only change.

Thanks,
Ian

> > +  fi
> > +  if echo "$result" | grep -q "Access to performance monitoring and observability operations is limited."
> > +  then
> > +    # Access is limited, so ignore.
> > +    continue
> > +  fi
> > +
> > +  # We failed to see the event and it is supported. Possibly the workload was
> > +  # too small so retry with something longer.
>
> Ok, maybe we want to check "<not counted>" events specifically.
>
> Thanks,
> Namhyung
>
>
> > +  result=$(perf stat -e "$p" perf bench internals synthesize 2>&1)
> > +  if echo "$result" | grep -q "$p"
> > +  then
> > +    # Event seen in output.
> > +    continue
> >    fi
> > +  echo "Error: event '$p' not printed in:"
> > +  echo "$result"
> > +  err=1
> >  done
> >
> > -exit 0
> > +trap - EXIT TERM INT
> > +exit $err
> > --
> > 2.46.0.792.g87dc391469-goog
> >