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Message-ID: <ZzdknoHqrJbojb6P@x1>
Date: Fri, 15 Nov 2024 12:11:26 -0300
From: Arnaldo Carvalho de Melo <acme@...nel.org>
To: Howard Chu <howardchu95@...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
On Fri, Nov 15, 2024 at 01:32:15AM -0800, Howard Chu wrote:
> 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.
> > 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\(\)$':
> ---- end(-1) ----
> 110: perf trace exit race : FAILED!
> In temp file:
> 0.000 true/3867219 syscalls:sys_enter_exit_group()
> 0.000 true/3867221 syscalls:sys_enter_exit_group()
> 0.000 true/3867223 syscalls:sys_enter_exit_group()
> 0.000 true/3867226 syscalls:sys_enter_exit_group()
> 0.000 true/3867250 syscalls:sys_enter_exit_group()
> 0.000 true/3867252 syscalls:sys_enter_exit_group()
> 0.000 true/3867255 syscalls:sys_enter_exit_group()
> 0.000 true/3867257 syscalls:sys_enter_exit_group()
> 0.000 true/3867259 syscalls:sys_enter_exit_group()
> 0.000 true/3867262 syscalls:sys_enter_exit_group()
>
> There are 10 lines of output which match the regex (I got the comm
> instead of pid), but it still falls into error, and inverse regex got
> nothing because they are all right.
You're right, I got confused with the other problem, namely in my case
some failures due to non-COMM resolution which ended up showing a few
that are not matching, so I thought it was about that.
Also at some point ShellCheck complained about some quoting and I ended
up adding that thinko, well spotted!
So with:
⬢ [acme@...lbox perf-tools-next]$ git diff
diff --git a/tools/perf/tests/shell/trace_exit_race.sh b/tools/perf/tests/shell/trace_exit_race.sh
index ce05d4e6e7133cd1..2e5581f550c50d16 100755
--- a/tools/perf/tests/shell/trace_exit_race.sh
+++ b/tools/perf/tests/shell/trace_exit_race.sh
@@ -21,7 +21,7 @@ trace_shutdown_race() {
for _ in $(seq 10); do
perf trace -e syscalls:sys_enter_exit_group true 2>>$file
done
- [ "$(grep -c -E '$regexp' $file)" = "10" ]
+ [ "$(grep -c -E "$regexp" $file)" = "10" ]
}
@@ -39,5 +39,5 @@ if [ $err != 0 ] && [ "${verbose}" = "1" ]; then
grep -v -E "$regexp" $file
fi
-rm -f ${file}
+echo rm -f ${file}
exit $err
⬢ [acme@...lbox perf-tools-next]$
I'm getting what you're getting:
root@...ber:~# perf test -v "trace exit race"
--- start ---
test child forked, pid 12139
Lines not matching the expected regexp: ' +[0-9]+\.[0-9]+ +true/[0-9]+ syscalls:sys_enter_exit_group\(\)$':
0.000 :12161/12161 syscalls:sys_enter_exit_group()
0.000 :12167/12167 syscalls:sys_enter_exit_group()
rm -f /tmp/temporary_file.v7REF
---- end(-1) ----
110: perf trace exit race : FAILED!
root@...ber:~# cat /tmp/temporary_file.v7REF
0.000 true/12147 syscalls:sys_enter_exit_group()
0.000 true/12151 syscalls:sys_enter_exit_group()
0.000 true/12153 syscalls:sys_enter_exit_group()
0.000 true/12155 syscalls:sys_enter_exit_group()
0.000 true/12157 syscalls:sys_enter_exit_group()
0.000 true/12159 syscalls:sys_enter_exit_group()
0.000 :12161/12161 syscalls:sys_enter_exit_group()
0.000 true/12163 syscalls:sys_enter_exit_group()
0.000 true/12165 syscalls:sys_enter_exit_group()
0.000 :12167/12167 syscalls:sys_enter_exit_group()
root@...ber:~# grep -E ' +[0-9]+\.[0-9]+ +true/[0-9]+ syscalls:sys_enter_exit_group\(\)$' /tmp/temporary_file.v7REF
0.000 true/12147 syscalls:sys_enter_exit_group()
0.000 true/12151 syscalls:sys_enter_exit_group()
0.000 true/12153 syscalls:sys_enter_exit_group()
0.000 true/12155 syscalls:sys_enter_exit_group()
0.000 true/12157 syscalls:sys_enter_exit_group()
0.000 true/12159 syscalls:sys_enter_exit_group()
0.000 true/12163 syscalls:sys_enter_exit_group()
0.000 true/12165 syscalls:sys_enter_exit_group()
root@...ber:~# grep -v -E ' +[0-9]+\.[0-9]+ +true/[0-9]+ syscalls:sys_enter_exit_group\(\)$' /tmp/temporary_file.v7REF
0.000 :12161/12161 syscalls:sys_enter_exit_group()
0.000 :12167/12167 syscalls:sys_enter_exit_group()
root@...ber:~# git difroot@...ber:~# perf test -v "trace exit race"
--- start ---
test child forked, pid 12139
Lines not matching the expected regexp: ' +[0-9]+\.[0-9]+ +true/[0-9]+ syscalls:sys_enter_exit_group\(\)$':
0.000 :12161/12161 syscalls:sys_enter_exit_group()
0.000 :12167/12167 syscalls:sys_enter_exit_group()
rm -f /tmp/temporary_file.v7REF
---- end(-1) ----
110: perf trace exit race : FAILED!
root@...ber:~# cat /tmp/temporary_file.v7REF
0.000 true/12147 syscalls:sys_enter_exit_group()
0.000 true/12151 syscalls:sys_enter_exit_group()
0.000 true/12153 syscalls:sys_enter_exit_group()
0.000 true/12155 syscalls:sys_enter_exit_group()
0.000 true/12157 syscalls:sys_enter_exit_group()
0.000 true/12159 syscalls:sys_enter_exit_group()
0.000 :12161/12161 syscalls:sys_enter_exit_group()
0.000 true/12163 syscalls:sys_enter_exit_group()
0.000 true/12165 syscalls:sys_enter_exit_group()
0.000 :12167/12167 syscalls:sys_enter_exit_group()
root@...ber:~# grep -E ' +[0-9]+\.[0-9]+ +true/[0-9]+ syscalls:sys_enter_exit_group\(\)$' /tmp/temporary_file.v7REF
0.000 true/12147 syscalls:sys_enter_exit_group()
0.000 true/12151 syscalls:sys_enter_exit_group()
0.000 true/12153 syscalls:sys_enter_exit_group()
0.000 true/12155 syscalls:sys_enter_exit_group()
0.000 true/12157 syscalls:sys_enter_exit_group()
0.000 true/12159 syscalls:sys_enter_exit_group()
0.000 true/12163 syscalls:sys_enter_exit_group()
0.000 true/12165 syscalls:sys_enter_exit_group()
root@...ber:~# grep -v -E ' +[0-9]+\.[0-9]+ +true/[0-9]+ syscalls:sys_enter_exit_group\(\)$' /tmp/temporary_file.v7REF
0.000 :12161/12161 syscalls:sys_enter_exit_group()
0.000 :12167/12167 syscalls:sys_enter_exit_group()
root@...ber:~# git diff
> > ---- end(-1) ----
> > 110: perf trace exit race : FAILED!
> > root@...ber:~#
> >
> > In this case we're not resolving the process COMM for some reason and
> > fallback to printing just the pid/tid, this will be fixed in a followup
> > patch.
> > - [ "$(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.
Right, see above.
> > 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:
Right again,
> 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)
>
> +++ 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>
Please see if you keep it, I ended up applying the slight variation
below, to avoid an repeating the last inverse grep.
Thanks a lot for reviewing and spotting that st00pid problem and
suggesting the improvement for the inverse grep!
- Arnaldo
diff --git a/tools/perf/tests/shell/trace_exit_race.sh b/tools/perf/tests/shell/trace_exit_race.sh
index ce05d4e6e7133cd1..8ea24f4256bc8f5e 100755
--- a/tools/perf/tests/shell/trace_exit_race.sh
+++ b/tools/perf/tests/shell/trace_exit_race.sh
@@ -15,13 +15,15 @@ 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
- [ "$(grep -c -E '$regexp' $file)" = "10" ]
+ result="$(grep -c -E "$regexp" $file)"
+ [ $result = $iter ]
}
@@ -35,8 +37,14 @@ trace_shutdown_race
err=$?
if [ $err != 0 ] && [ "${verbose}" = "1" ]; then
- echo "Lines not matching the expected regexp: '$regexp':"
- grep -v -E "$regexp" $file
+ lines_not_matching=$(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}
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