From: Sandipan Das <sandipan.das@amd.com>
To: <linux-perf-users@vger.kernel.org>, <linux-kernel@vger.kernel.org>
Cc: <peterz@infradead.org>, <mingo@redhat.com>, <acme@kernel.org>,
<namhyung@kernel.org>, <mark.rutland@arm.com>,
<alexander.shishkin@linux.intel.com>, <jolsa@kernel.org>,
<irogers@google.com>, <adrian.hunter@intel.com>,
<kan.liang@linux.intel.com>, <tglx@linutronix.de>, <bp@alien8.de>,
<dave.hansen@linux.intel.com>, <x86@kernel.org>, <hpa@zytor.com>,
<eranian@google.com>, <songliubraving@meta.com>,
<ravi.bangoria@amd.com>, <ananth.narayan@amd.com>,
<sandipan.das@amd.com>
Subject: [PATCH 0/4] perf/x86/amd/uncore: Overflow handling enhancements
Date: Wed, 9 Apr 2025 13:27:05 +0530 [thread overview]
Message-ID: <cover.1744184837.git.sandipan.das@amd.com> (raw)
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
next reply other threads:[~2025-04-09 7:57 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-04-09 7:57 Sandipan Das [this message]
2025-04-09 7:57 ` [PATCH 1/4] perf/x86/amd/uncore: Remove unused member from amd_uncore_ctx Sandipan Das
2025-04-09 7:57 ` [PATCH 2/4] perf/x86/amd/uncore: Use hrtimer for handling overflows Sandipan Das
2025-04-10 8:20 ` Peter Zijlstra
2025-04-10 8:40 ` Sandipan Das
2025-04-09 7:57 ` [PATCH 3/4] perf/x86/amd/uncore: Add parameter to configure hrtimer Sandipan Das
2025-04-09 7:57 ` [PATCH 4/4] perf/x86/amd/uncore: Prevent UMC counters from saturating Sandipan Das
2025-04-16 19:15 ` Song Liu
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