Re: [PATCH v3] perf/test: fix perf ftrace test on s390

[Namhyung Kim <namhyung@kernel.org>]

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@linux.ibm.com>
> Suggested-by: Sven Schnelle <svens@linux.ibm.com>
> Suggested-by: Namhyung Kim <namhyung@kernel.org>

Acked-by: Namhyung Kim <namhyung@kernel.org>

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
>