Re: [PATCH] perf test: perf stat tests fails on s390

[Aaron Tomlin]

On Wed, Sep 02, 2026 at 01:52:18PM +0200, Thomas Richter wrote:
> The test case 'perf stat tests' fails on s390 z/VM machines. The
> root cause is the unsupported CPU measurement facility on z/VM.
> Therefore the events cycles and instructions do not exist and
> are unsupported. This cause the subtest
>   Hide zero events stat test
> to fail.
> 
> Output before:
>  # perf test 116
>  116: perf stat tests  : FAILED!
> 
>  === Test Summary ===
>  Passed main tests : 0
>  Passed subtests   : 0
>  Skipped tests     : 0
>  Failed tests      : 1
>  List of failed tests:
>   116: perf stat tests
>  #
> 
> Output after:
>  # ./perf test 116
>  116: perf stat tests  : Ok
> 
>  === Test Summary ===
>  Passed main tests : 1
>  Passed subtests   : 0
>  Skipped tests     : 0
>  Failed tests      : 0
>  #
> 
> Fixes: 64724095a33f ("perf stat: Add --hide-zero-events option to suppress zero-count events")
> Cc: Aaron Tomlin <atomlin@xxxxxxxxxxx>
> Cc: Ian Rogers <irogers@xxxxxxxxxx>
> Cc: Namhyung Kim <namhyung@xxxxxxxxxx>
> Signed-off-by: Thomas Richter <tmricht@xxxxxxxxxxxxx>
> ---
>  tools/perf/tests/shell/stat.sh | 5 +++++
>  1 file changed, 5 insertions(+)
> 
> diff --git a/tools/perf/tests/shell/stat.sh b/tools/perf/tests/shell/stat.sh
> index 298ce454b45a..41bac99300a1 100755
> --- a/tools/perf/tests/shell/stat.sh
> +++ b/tools/perf/tests/shell/stat.sh
> @@ -583,6 +583,11 @@ test_hide_zero_events_stat() {
>    # Check that --metric-only works with --hide-zero-events
>    if ! perf stat --hide-zero-events --metric-only -e instructions,cycles true > "${stat_output}" 2>&1
>    then
> +    grep -q 'No supported events found' "${stat_output}"
> +    if [ $? -eq 0 ]; then
> +      echo "Hide zero events stat test [Skipped - events not supported]"
> +      return
> +    fi
>      echo "Hide zero events stat test [Failed - metric-only command failed]"
>      err=1
>      return
> -- 
> 2.55.0
> 

Hi Thomas,

This makes sense.

However, please see the valid feedback from Sashiko [1]. Otherwise:

Reviewed-by: Aaron Tomlin <atomlin@xxxxxxxxxxx>

[1]: https://sashiko.dev/#/patchset/20260902115218.2977412-1-tmricht%40linux.ibm.com

Kind regards,
-- 
Aaron Tomlin