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Message-ID: <CAH0uvohi_8_itv+jDjCEvrprakhp5w7=GvWw+hJG4gTLwJQjog@mail.gmail.com>
Date: Fri, 15 Nov 2024 01:32:15 -0800
From: Howard Chu <howardchu95@...il.com>
To: arnaldo.melo@...il.com
Cc: Benjamin Peterson <benjamin@...flow.com>, Adrian Hunter <adrian.hunter@...el.com>,
Alexander Shishkin <alexander.shishkin@...ux.intel.com>, Ian Rogers <irogers@...gle.com>,
Ingo Molnar <mingo@...hat.com>, Jiri Olsa <jolsa@...nel.org>,
Kan Liang <kan.liang@...ux.intel.com>, Mark Rutland <mark.rutland@....com>,
Namhyung Kim <namhyung@...nel.org>, Peter Zijlstra <peterz@...radead.org>,
Linux Kernel Mailing List <linux-kernel@...r.kernel.org>, linux-perf-users@...r.kernel.org
Subject: Re: [PATCH 1/1] perf tests shell trace_exit_race: Show what went
wrong in verbose mode
Hello Arnaldo,
On Thu, Nov 14, 2024 at 1:19 PM <arnaldo.melo@...il.com> wrote:
>
> This is in the tmp.perf-tools-next branch at:
>
> https://git.kernel.org/pub/scm/linux/kernel/git/perf/perf-tools-next.git
>
> I'll later add another patch adding the --no-comm to the 'perf trace'
> command line and will adjust the regexp.
>
> - Arnaldo
>
> ---
>
> 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()
This output looks good but I got an empty grep -v:
perf $ ./perf test 110 -v
110: perf trace exit race :
Running (1
--- start ---
test child forked, pid 3865874
Lines not matching the expected regexp: ' +[0-9]+\.[0-9]+ +true/[0-9]+
syscalls:sys_enter_exit_group\(\)$':
---- end(-1) ----
110: perf trace exit race : FAILED!
In temp file:
0.000 true/3867219 syscalls:sys_enter_exit_group()
0.000 true/3867221 syscalls:sys_enter_exit_group()
0.000 true/3867223 syscalls:sys_enter_exit_group()
0.000 true/3867226 syscalls:sys_enter_exit_group()
0.000 true/3867250 syscalls:sys_enter_exit_group()
0.000 true/3867252 syscalls:sys_enter_exit_group()
0.000 true/3867255 syscalls:sys_enter_exit_group()
0.000 true/3867257 syscalls:sys_enter_exit_group()
0.000 true/3867259 syscalls:sys_enter_exit_group()
0.000 true/3867262 syscalls:sys_enter_exit_group()
There are 10 lines of output which match the regex (I got the comm
instead of pid), but it still falls into error, and inverse regex got
nothing because they are all right.
> ---- 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.
>
> Cc: Adrian Hunter <adrian.hunter@...el.com>
> Cc: Alexander Shishkin <alexander.shishkin@...ux.intel.com>
> Cc: Howard Chu <howardchu95@...il.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>
> To: Benjamin Peterson <benjamin@...flow.com>
> Signed-off-by: Arnaldo Carvalho de Melo <acme@...hat.com>
> ---
> tools/perf/tests/shell/trace_exit_race.sh | 14 +++++++++++++-
> 1 file changed, 13 insertions(+), 1 deletion(-)
>
> diff --git a/tools/perf/tests/shell/trace_exit_race.sh b/tools/perf/tests/shell/trace_exit_race.sh
> index 3cf2d71a5c3b9278..ce05d4e6e7133cd1 100755
> --- a/tools/perf/tests/shell/trace_exit_race.sh
> +++ b/tools/perf/tests/shell/trace_exit_race.sh
> @@ -11,11 +11,17 @@
>
> skip_if_no_perf_trace || exit 2
>
> +if [ "$1" = "-v" ]; then
> + verbose="1"
> +fi
> +
> +regexp=" +[0-9]+\.[0-9]+ +true/[0-9]+ syscalls:sys_enter_exit_group\(\)$"
> +
> trace_shutdown_race() {
> for _ in $(seq 10); do
> perf trace -e syscalls:sys_enter_exit_group true 2>>$file
> done
> - [ "$(grep -c -E ' +[0-9]+\.[0-9]+ +true/[0-9]+ syscalls:sys_enter_exit_group\(\)$' $file)" = "10" ]
> + [ "$(grep -c -E '$regexp' $file)" = "10" ]
shouldn't this be
[ "$(grep -c -E "$regexp" $file)" = "10" ]
?
In shell script single quote doesn't interpolate, in this case you are
literally grepping the string "$regexp". After changing this to double
quotes it works for me.
> }
>
>
> @@ -27,5 +33,11 @@ export PERF_CONFIG=/dev/null
>
> trace_shutdown_race
> err=$?
> +
> +if [ $err != 0 ] && [ "${verbose}" = "1" ]; then
> + echo "Lines not matching the expected regexp: '$regexp':"
Also, I think there is a case, where $err != 0 can come from not
having 10 matches, say 4 (because of racing), and these 4 can all be
correct, the inverse grep -v won't match anything, results in an empty
output as above:
Lines not matching the expected regexp: ' +[0-9]+\.[0-9]+ +true/[0-9]+
syscalls:sys_enter_exit_group\(\)$':
---- end(-1) ----
> + grep -v -E "$regexp" $file
> +fi
> +
> rm -f ${file}
> exit $err
> --
> 2.47.0
>
Maybe this? (based on your test)
diff --git a/tools/perf/tests/shell/trace_exit_race.sh
b/tools/perf/tests/shell/trace_exit_race.sh
index ce05d4e6e713..3633907e9e2a 100755
--- a/tools/perf/tests/shell/trace_exit_race.sh
+++ b/tools/perf/tests/shell/trace_exit_race.sh
@@ -16,12 +16,15 @@ if [ "$1" = "-v" ]; then
fi
regexp=" +[0-9]+\.[0-9]+ +true/[0-9]+ syscalls:sys_enter_exit_group\(\)$"
+iter=15
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
- [ "$(grep -c -E '$regexp' $file)" = "10" ]
+
+ result="$(grep -c -E "$regexp" $file)"
+ [ $result = $iter ]
}
@@ -35,8 +38,12 @@ trace_shutdown_race
err=$?
if [ $err != 0 ] && [ "${verbose}" = "1" ]; then
- echo "Lines not matching the expected regexp: '$regexp':"
- grep -v -E "$regexp" $file
+ if grep -q -v -E "$regexp" $file; then
+ echo "Lines not matching the expected regexp: '$regexp':"
+ grep -v -E "$regexp" $file
+ else
+ echo "Missing output, expected $iter but only got $result"
+ fi
fi
rm -f ${file}
Reviewed-by: Howard Chu <howardchu95@...il.com>
Thanks,
Howard
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