linux-kernel - Re: [PATCH 1/2] perf test shell trace_exit_race: Show what went wrong in verbose mode

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Message-ID: <CAH0uvog__5b4PC8MEk_GL2Ek0pYU7fJ1XfdHyDiwFTBYN0tuxw@mail.gmail.com>
Date: Fri, 15 Nov 2024 10:26:53 -0800
From: Howard Chu <howardchu95@...il.com>
To: Arnaldo Carvalho de Melo <acme@...nel.org>
Cc: Benjamin Peterson <benjamin@...flow.com>, Namhyung Kim <namhyung@...nel.org>, 
	Ingo Molnar <mingo@...nel.org>, Thomas Gleixner <tglx@...utronix.de>, Jiri Olsa <jolsa@...nel.org>, 
	Ian Rogers <irogers@...gle.com>, Adrian Hunter <adrian.hunter@...el.com>, 
	Kan Liang <kan.liang@...ux.intel.com>, Clark Williams <williams@...hat.com>, 
	linux-kernel@...r.kernel.org, linux-perf-users@...r.kernel.org, 
	Arnaldo Carvalho de Melo <acme@...hat.com>, Alexander Shishkin <alexander.shishkin@...ux.intel.com>, 
	Ingo Molnar <mingo@...hat.com>, Mark Rutland <mark.rutland@....com>, 
	Peter Zijlstra <peterz@...radead.org>
Subject: Re: [PATCH 1/2] perf test shell trace_exit_race: Show what went wrong
 in verbose mode

Hello Arnaldo,

On Fri, Nov 15, 2024 at 7:36 AM Arnaldo Carvalho de Melo
<acme@...nel.org> wrote:
>
> From: Arnaldo Carvalho de Melo <acme@...hat.com>
>
> If it fails we need to check what was the reason, what were the lines
> that didn't match the expected format, so:
>
>   root@...ber:~# perf test -v "trace exit race"
>   --- start ---
>   test child forked, pid 2028724
>   Lines not matching the expected regexp: ' +[0-9]+\.[0-9]+ +true/[0-9]+ syscalls:sys_enter_exit_group\(\)$':
>        0.000 :2028750/2028750 syscalls:sys_enter_exit_group()
>   ---- end(-1) ----
>   110: perf trace exit race                                            : FAILED!
>   root@...ber:~#
>
> In this case we're not resolving the process COMM for some reason and
> fallback to printing just the pid/tid, this will be fixed in a followup
> patch.
>
> Howard Chu spotted a problem with single code surrounding a regexp, that
> made the test always fail, but since there were some failures when I
> tested (COMM not being resolved in some of the results) the end inverse
> grep would show some lines and thus didn't notice the single quote
> problem.
>
> He also provided a patch to test if less than the number of expected
> matches took place but all of them with the expected output, in which
> case the inverse grep wouldn't show anything, confusing the tester.
>
> Reviewed-by: Howard Chu <howardchu95@...il.com>
> Cc: Adrian Hunter <adrian.hunter@...el.com>
> Cc: Alexander Shishkin <alexander.shishkin@...ux.intel.com>
> Cc: Benjamin Peterson <benjamin@...flow.com>
> Cc: Ian Rogers <irogers@...gle.com>
> Cc: Ingo Molnar <mingo@...hat.com>
> Cc: Jiri Olsa <jolsa@...nel.org>
> Cc: Kan Liang <kan.liang@...ux.intel.com>
> Cc: Mark Rutland <mark.rutland@....com>
> Cc: Namhyung Kim <namhyung@...nel.org>
> Cc: Peter Zijlstra <peterz@...radead.org>
> Link: https://lore.kernel.org/lkml/ZzdknoHqrJbojb6P@x1
> Signed-off-by: Arnaldo Carvalho de Melo <acme@...hat.com>
> ---
>  tools/perf/tests/shell/trace_exit_race.sh | 24 +++++++++++++++++++++--
>  1 file changed, 22 insertions(+), 2 deletions(-)
>
> diff --git a/tools/perf/tests/shell/trace_exit_race.sh b/tools/perf/tests/shell/trace_exit_race.sh
> index 3cf2d71a5c3b9278..8ea24f4256bc8f5e 100755
> --- a/tools/perf/tests/shell/trace_exit_race.sh
> +++ b/tools/perf/tests/shell/trace_exit_race.sh
> @@ -11,11 +11,19 @@
>
>  skip_if_no_perf_trace || exit 2
>
> +if [ "$1" = "-v" ]; then
> +       verbose="1"
> +fi
> +
> +iter=10
> +regexp=" +[0-9]+\.[0-9]+ +true/[0-9]+ syscalls:sys_enter_exit_group\(\)$"
> +
>  trace_shutdown_race() {
> -       for _ in $(seq 10); do
> +       for _ in $(seq $iter); do
>                 perf trace -e syscalls:sys_enter_exit_group true 2>>$file
>         done
> -       [ "$(grep -c -E ' +[0-9]+\.[0-9]+ +true/[0-9]+ syscalls:sys_enter_exit_group\(\)$' $file)" = "10" ]
> +       result="$(grep -c -E "$regexp" $file)"
> +       [ $result = $iter ]
>  }
>
>
> @@ -27,5 +35,17 @@ export PERF_CONFIG=/dev/null
>
>  trace_shutdown_race
>  err=$?
> +
> +if [ $err != 0 ] && [ "${verbose}" = "1" ]; then
> +       lines_not_matching=$(mktemp /tmp/temporary_file.XXXXX)
> +       if grep -v -E "$regexp" $file > $lines_not_matching ; then
> +               echo "Lines not matching the expected regexp: '$regexp':"
> +               cat $lines_not_matching
> +       else
> +               echo "Missing output, expected $iter but only got $result"
> +       fi
> +       rm -f $lines_not_matching
> +fi
> +
>  rm -f ${file}
>  exit $err

LGTM.

Thanks,
Howard

> --
> 2.47.0
>