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Date: Tue, 9 Jan 2024 16:37:18 +0000
From: Mark Rutland <mark.rutland@arm.com>
To: Ian Rogers <irogers@google.com>
Cc: "Liang, Kan" <kan.liang@linux.intel.com>,
	Arnaldo Carvalho de Melo <acme@kernel.org>,
	Kan Liang <kan.liang@intel.com>,
	Adrian Hunter <adrian.hunter@intel.com>,
	Jiri Olsa <jolsa@kernel.org>, Namhyung Kim <namhyung@kernel.org>,
	linux-perf-users@vger.kernel.org,
	Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
Subject: Re: perf test hybrid failing on 14700K
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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@FVFF77S0Q05N.cambridge.arm.com/
  https://lore.kernel.org/lkml/ZV-ItX1eMeIdo_00@FVFF77S0Q05N.cambridge.arm.com/

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

Thanks,
Mark.