Re: [PATCH v2] perf pmu: Skip test on Arm64 when #slots is zero

[Leo Yan <leo.yan@arm.com>]

On Wed, May 13, 2026 at 06:10:00AM -0700, Ian Rogers wrote:

[...]

> We get this failure for these metrics on x86 when building perf with
> JEVENTS_ARCH=all. Rather than expecting the parse failure perhaps we
> should just always return true in tool_pmu__read_event:
> https://web.git.kernel.org/pub/scm/linux/kernel/git/perf/perf-tools-next.git/tree/tools/perf/util/tool_pmu.c#n421

I considered returning true when slots == 0 so can mute parser error
and allow the test to pass. However, if so platforms which do not
support #slots would be able to use those metrics and generate
meaningless statistics.

I would keep the parser errors so this is a reminding when users wrongly
use unsupported metrics.

> I guess the problem there is that when these metrics are broken (no
> slots value) you can't distinguish this case from other valid cases.

IMO, this is a test design issue: tests should validate metrics while
remaining hardware-agnostic. Hardware-specific cases should either run
only on supported platforms, or the tests should be refined to run
transparently across different hardware.

> Reviewed-by: Ian Rogers <irogers@google.com>

Thanks for review!

Leo