Re: [PATCH] perf/tests: Fix tests 84 and 86 Add --metric-only on s390

[Heiko Carstens <hca@linux.ibm.com>]

On Tue, Apr 15, 2025 at 03:45:53PM +0200, Thomas Richter wrote:
> On s390x z/VM machines the CPU Measurement Facility is not available.
> Events cycles and instructions do not exist.
> Running above tests on s390 z/VM always fails with this error:
> 
>  # ./perf test 84 86
>  84: perf stat JSON output linter          : FAILED!
>  86: perf stat STD output linter           : FAILED!
>  #

I would guess this fails also for KVM guests?

> diff --git a/tools/perf/tests/shell/lib/stat_output.sh b/tools/perf/tests/shell/lib/stat_output.sh
> index 4d4aac547f01..a708dedf7d9d 100644
> --- a/tools/perf/tests/shell/lib/stat_output.sh
> +++ b/tools/perf/tests/shell/lib/stat_output.sh
> @@ -151,6 +151,11 @@ check_per_socket()
>  check_metric_only()
>  {
>  	echo -n "Checking $1 output: metric only "
> +	if [ "$(uname -m)" = "s390x" ] && grep -q z/VM /proc/sysinfo
> +	then
> +		echo "[Skip] not supported on z/VM"
> +		return
> +	fi

Wouldn't it be better to test for the availability of the CPU-measurement
counter facility? That is: test if facility number 67 is present in the
facilities field of /proc/cpuinfo.