Re: perf test hybrid failing on 14700K

[Mark Rutland]

On Fri, Jan 05, 2024 at 09:21:21AM -0800, Ian Rogers wrote:
> While much has been done in the perf tool to work around latent issues
> with ARM's PMU drivers and the behavior changes they have instigated,
> except for 5c816728651a ("arm_pmu: Add PERF_PMU_CAP_EXTENDED_HW_TYPE
> capability") where I wrote the original version, there doesn't seem to
> have been progress made on the ARM PMU driver nor on ARM testing -
> which was why such an issue could exist for so long, across numerous
> Linux releases and ultimately break Hector and Martin.

Ian, which latent issues in the PMU drivers are you referring to?

I already pointed out that one of the problems you have claimed to be a driver
bug is actually due to userspace incorrectly detecting support for the extended
HW type, and I suggested some options which you have so far ignored:

  https://lore.kernel.org/lkml/ZV-CUlQhlkdOzfFZ@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxx/
  https://lore.kernel.org/lkml/ZV-ItX1eMeIdo_00@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxx/

I agree that testing is a problem, and we need to do better from the arm side.

Thanks,
Mark.