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

Mi, Dapeng
2026-04-13T01:19:54Z

On 4/13/2026 9:01 AM, Dapeng Mi wrote:
> 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.

The unit test patch:
https://lore.kernel.org/all/20260413010920.546501-1-dapeng1.mi@linux.intel.com/

Thanks.

>
> 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