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

From: Sandipan Das
Date: Wed Apr 09 2025 - 03:59:55 EST


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(-)

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2.43.0