Re: [PATCH v3] perf/test: fix perf ftrace test on s390
From: Namhyung Kim
Date: Tue Nov 19 2024 - 14:08:18 EST
On Tue, Nov 19, 2024 at 07:48:56AM +0100, Thomas Richter wrote:
> On s390 the perf test case ftrace sometimes fails as follows:
>
> # ./perf test ftrace
> 79: perf ftrace tests : FAILED!
> #
>
> The failure depends on the kernel .config file. Some configurations
> always work fine, some do not. The ftrace profile test mostly fails,
> because the ring buffer was not large enough, and some lines
> (especially the interesting ones with nanosleep in it) where dropped.
>
> To achieve success for all tested kernel configurations, enlarge
> the buffer to store the traces completely without wrapping.
> The default buffer size is too small for all kernel configurations.
> Set the buffer size of for the ftrace profile test to 16 MB.
>
> Output after:
> # ./perf test ftrace
> 79: perf ftrace tests : Ok
> #
>
> Signed-off-by: Thomas Richter <tmricht@xxxxxxxxxxxxx>
> Suggested-by: Sven Schnelle <svens@xxxxxxxxxxxxx>
> Suggested-by: Namhyung Kim <namhyung@xxxxxxxxxx>
Acked-by: Namhyung Kim <namhyung@xxxxxxxxxx>
Thanks,
Namhyung
> ---
> tools/perf/tests/shell/ftrace.sh | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/tools/perf/tests/shell/ftrace.sh b/tools/perf/tests/shell/ftrace.sh
> index a6ee740f0d7e..a785a6274922 100755
> --- a/tools/perf/tests/shell/ftrace.sh
> +++ b/tools/perf/tests/shell/ftrace.sh
> @@ -67,7 +67,7 @@ test_ftrace_latency() {
>
> test_ftrace_profile() {
> echo "perf ftrace profile test"
> - perf ftrace profile sleep 0.1 > "${output}"
> + perf ftrace profile -m 16M sleep 0.1 > "${output}"
> grep ^# "${output}"
> grep sleep "${output}"
> grep schedule "${output}"
> --
> 2.47.0
>