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Message-ID: <CAP-5=fXUfdmEKDF7JW7bTx+=WMWa79mBM5BxX6OhpTUjanh8xQ@mail.gmail.com>
Date: Fri, 23 Jun 2023 16:23:53 -0700
From: Ian Rogers <irogers@...gle.com>
To: Namhyung Kim <namhyung@...nel.org>
Cc: Arnaldo Carvalho de Melo <acme@...nel.org>,
Jiri Olsa <jolsa@...nel.org>,
Adrian Hunter <adrian.hunter@...el.com>,
Peter Zijlstra <peterz@...radead.org>,
Ingo Molnar <mingo@...nel.org>,
LKML <linux-kernel@...r.kernel.org>,
linux-perf-users@...r.kernel.org,
Kan Liang <kan.liang@...ux.intel.com>
Subject: Re: [PATCH 2/2] perf test: Skip metrics w/o event name in stat STD
output linter
On Fri, Jun 23, 2023 at 4:01 PM Namhyung Kim <namhyung@...nel.org> wrote:
>
> This test checks if the output of perf stat to match event names and
> metrics. So it wants the output lines to have both event name and
> metric. Otherwise it should skip the line.
>
> On AMD machines, the instruction event has two metrics and they are printed
> in separate lines. It makes the line without event name like below:
>
> # perf stat -a sleep 1
>
> Performance counter stats for 'system wide':
>
> 64,383.34 msec cpu-clock # 64.048 CPUs utilized
> 14,526 context-switches # 225.617 /sec
> 112 cpu-migrations # 1.740 /sec
> 190 page-faults # 2.951 /sec
> 807,558,652 cycles # 0.013 GHz (83.30%)
> 69,809,799 stalled-cycles-frontend # 8.64% frontend cycles idle (83.30%)
> 196,983,266 stalled-cycles-backend # 24.39% backend cycles idle (83.30%)
> 424,876,008 instructions # 0.53 insn per cycle
> (here) ---> # 0.46 stalled cycles per insn (83.30%)
> 97,788,321 branches # 1.519 M/sec (83.34%)
> 4,147,377 branch-misses # 4.24% of all branches (83.46%)
>
> 1.005241409 seconds time elapsed
>
> Also modern Intel machines have TopDown metrics which also don't have
> event names.
>
> # perf stat -a sleep 1
>
> Performance counter stats for 'system wide':
>
> 8,015.39 msec cpu-clock # 7.996 CPUs utilized
> 5,823 context-switches # 726.477 /sec
> 189 cpu-migrations # 23.580 /sec
> 139 page-faults # 17.342 /sec
> 435,139,308 cycles # 0.054 GHz
> 193,891,345 instructions # 0.45 insn per cycle
> 42,773,028 branches # 5.336 M/sec
> 2,298,113 branch-misses # 5.37% of all branches
> TopdownL1 # 25.5 % tma_backend_bound
> /--> # 7.9 % tma_bad_speculation
> (here) --+ # 55.7 % tma_frontend_bound
> \--> # 10.9 % tma_retiring
>
> 1.002395924 seconds time elapsed
>
> There is a check to skip TopdownL1 and TopdownL2 specifically but it
> does not cover every affected lines.
>
> So there is another check to skip the line if it has nothing on the left
> side of # sign. Well.. it seems ok but that's not enough too.
>
> When aggregation mode (like --per-socket or --per-thread) is used, it
> adds some prefix (e.g. CPU socket, task name and PID) in the output
> line. So the test code ignores them to normalize result.
>
> A problem can happen for per-thread mode when task name contains one or
> more spaces. It'd only ignore the first part of the task name, and it
> thinks there's something more in the line so it would not skip.
>
> # perf stat -a --perf-thread sleep 1
> ...
> perf-21276 # 70.2 % tma_backend_bound
> perf-21276 # 3.9 % tma_bad_speculation
> perf-21276 # 10.5 % tma_frontend_bound
> perf-21276 # 15.3 % tma_retiring
> ^^^^^^^^^^
> (ignored)
>
> my task-21328 # 70.2 % tma_backend_bound
> my task-21328 # 3.9 % tma_bad_speculation
> my task-21328 # 10.5 % tma_frontend_bound
> my task-21328 # 15.3 % tma_retiring
> ^^
> (ignored)
>
> So I think it should look at the metric names instead. Add skip_metric
> to hold the list of names to skip. It would contain 'stalled cycles per
> insn' and metrics started by 'tma_'.
>
> Fixes: 99a04a48f225 ("perf test: Add test case for the standard 'perf stat' output")
> Cc: Kan Liang <kan.liang@...ux.intel.com>
> Signed-off-by: Namhyung Kim <namhyung@...nel.org>
Acked-by: Ian Rogers <irogers@...gle.com>
Thanks,
Ian
> ---
> tools/perf/tests/shell/stat+std_output.sh | 16 ++++++++--------
> 1 file changed, 8 insertions(+), 8 deletions(-)
>
> diff --git a/tools/perf/tests/shell/stat+std_output.sh b/tools/perf/tests/shell/stat+std_output.sh
> index 1f70aab45184..f972b31fa0c2 100755
> --- a/tools/perf/tests/shell/stat+std_output.sh
> +++ b/tools/perf/tests/shell/stat+std_output.sh
> @@ -12,8 +12,7 @@ stat_output=$(mktemp /tmp/__perf_test.stat_output.std.XXXXX)
>
> event_name=(cpu-clock task-clock context-switches cpu-migrations page-faults stalled-cycles-frontend stalled-cycles-backend cycles instructions branches branch-misses)
> event_metric=("CPUs utilized" "CPUs utilized" "/sec" "/sec" "/sec" "frontend cycles idle" "backend cycles idle" "GHz" "insn per cycle" "/sec" "of all branches")
> -
> -metricgroup_name=(TopdownL1 TopdownL2)
> +skip_metric=("stalled cycles per insn" "tma_")
>
> cleanup() {
> rm -f "${stat_output}"
> @@ -58,13 +57,14 @@ function commachecker()
>
> main_body=$(echo $line | cut -d' ' -f$prefix-)
> x=${main_body%#*}
> - # Check default metricgroup
> - y=$(echo $x | tr -d ' ')
> - [ "$y" = "" ] && continue
> - for i in "${!metricgroup_name[@]}"; do
> - [[ "$y" == *"${metricgroup_name[$i]}"* ]] && break
> + [ "$x" = "" ] && continue
> +
> + # Skip metrics without event name
> + y=${main_body#*#}
> + for i in "${!skip_metric[@]}"; do
> + [[ "$y" == *"${skip_metric[$i]}"* ]] && break
> done
> - [[ "$y" == *"${metricgroup_name[$i]}"* ]] && continue
> + [[ "$y" == *"${skip_metric[$i]}"* ]] && continue
>
> # Check default event
> for i in "${!event_name[@]}"; do
> --
> 2.41.0.162.gfafddb0af9-goog
>
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