linux-kernel - [PATCH 0/4] perf/x86/amd/uncore: Overflow handling enhancements

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Message-ID: <cover.1744184837.git.sandipan.das@amd.com>
Date: Wed, 9 Apr 2025 13:27:05 +0530
From: Sandipan Das <sandipan.das@....com>
To: <linux-perf-users@...r.kernel.org>, <linux-kernel@...r.kernel.org>
CC: <peterz@...radead.org>, <mingo@...hat.com>, <acme@...nel.org>,
	<namhyung@...nel.org>, <mark.rutland@....com>,
	<alexander.shishkin@...ux.intel.com>, <jolsa@...nel.org>,
	<irogers@...gle.com>, <adrian.hunter@...el.com>, <kan.liang@...ux.intel.com>,
	<tglx@...utronix.de>, <bp@...en8.de>, <dave.hansen@...ux.intel.com>,
	<x86@...nel.org>, <hpa@...or.com>, <eranian@...gle.com>,
	<songliubraving@...a.com>, <ravi.bangoria@....com>, <ananth.narayan@....com>,
	<sandipan.das@....com>
Subject: [PATCH 0/4] perf/x86/amd/uncore: Overflow handling enhancements

Uncore counters on AMD processors either roll over or saturate on
overflow and the amd-uncore driver has no way of knowing if multiple
overflows have occurred between two successive pmu->read() requests for
an event. This makes the user-visible counter values inaccurate. Solve
this by periodically initiating pmu->read() in order to keep prev_count
up-to-date. The approach follows Intel's precedent in handling uncore
counters.

Sandipan Das (4):
  perf/x86/amd/uncore: Remove unused member from amd_uncore_ctx
  perf/x86/amd/uncore: Use hrtimer for handling overflows
  perf/x86/amd/uncore: Add parameter to configure hrtimer
  perf/x86/amd/uncore: Prevent UMC counters from saturating

 arch/x86/events/amd/uncore.c | 109 ++++++++++++++++++++++++++++++++++-
 1 file changed, 107 insertions(+), 2 deletions(-)

-- 
2.43.0