[PATCH 0/2] Fix 2 bugs for Intel auto counter reload (ACR)

Dapeng Mi
2026-04-13T01:06:40Z

This small patch-set fixes 2 issues in auto counter reload support.
- The stale ACR mask is not cleared before setting a new one. Patch 1/2
fixes this issue.
- PMI is enabled by default for self-reloaded ACR events which causes
suspicious NMI warning. Patch 2/2 fixes this issue.

Besides an ACR unit test is added into perf tests which would be posted
in a separate session.

Tests:

Run below ACR sampling commands on CWF and NVL (hybrid platform), no
issues are found.

a. Non-PEBS ACR sampling

perf record -e '{instructions/period=20000,acr_mask=0x2/u,cycles/period=40000,acr_mask=0x3/u}' ~/test

b. PEBS ACR sampling

perf record -e '{instructions/period=20000,acr_mask=0x2/pu,cycles/period=40000,acr_mask=0x3/u}' ~/test

Dapeng Mi (2):
perf/x86/intel: Clear stale ACR mask before updating new mask
perf/x86/intel: Disable PMI for self-reloaded ACR events

arch/x86/events/intel/core.c | 20 ++++++++++++++++----
arch/x86/events/perf_event.h | 10 ++++++++++
2 files changed, 26 insertions(+), 4 deletions(-)

base-commit: 9805ed3c91478b08a586861b874bd8b6a2fed648
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2.34.1