Re: [Patch v3 1/8] perf/x86/intel: Remove anythread_deprecated bit from perf_capabilities

[Mi, Dapeng]

On 6/16/2026 6:02 PM, Peter Zijlstra wrote:
> On Mon, Jun 15, 2026 at 08:59:29AM +0800, Mi, Dapeng wrote:
>> On 6/12/2026 5:46 PM, Peter Zijlstra wrote:
>>> On Fri, Jun 12, 2026 at 05:01:07PM +0800, Dapeng Mi wrote:
>>>> AnyThread mode deprecation is enumerated by CPUID.0AH:EDX[15] instead of
>>>> PERF_CAPABILITIES MSR. It's not a good practice to define a bit to
>>>> represent "anythread deprecation" in perf_capabilities. It leads to the
>>>> anythread_deprecated bit could be overwritten by the real value of
>>>> PERF_CAPABILITIES MSR, just like the below code in update_pmu_cap() does.
>>>>
>>>> ```
>>>> if (!intel_pmu_broken_perf_cap()) {
>>>> 	/* Perf Metric (Bit 15) and PEBS via PT (Bit 16) are hybrid enumeration */
>>>> 	rdmsrq(MSR_IA32_PERF_CAPABILITIES, hybrid(pmu, intel_cap).capabilities);
>>>> }
>>>> ```
>>>>
>>>> It leads to the anythread_deprecated bit is cleared to 0 and the "any"
>>>> attribute is incorrectly shown in the /sys/devices/cpu/format/ folder on
>>>> these support Perfmon v6 platforms, like Clearwater Forest.
>>>>
>>>> ```
>>>> $grep . /sys/devices/cpu/format/*
>>>> /sys/devices/cpu/format/acr_mask:config2:0-63
>>>> /sys/devices/cpu/format/any:config:21
>>>> /sys/devices/cpu/format/cmask:config:24-31
>>>> ```
>>>>
>>>> So remove the anythread_deprecated bit from perf_capabilities structure
>>>> and directly depends on CPUID.0AH:EDX[15] to judge if anythread is
>>>> deprecated.
>>> Again, no markdown please. I've stripped it from these patches.
>> My bad. Thanks a lot.
>>
>> BTW, Peter, have you pull these patches? I didn't see them in perf/core or
>> perf/urgent branches. Sashiko reports a defect about "Patch 5/8:
>> perf/x86/intel: Validate the return value of intel_pmu_init_hybrid()". If
>> not, I would post a v4 patchset to fix the defect. Thanks.
>>
> I had them in queue:perf/core, but realized it was *really* late in the
> window. I'll probably move them into tip post -rc1. If there's a new
> version by then, I'll be sure to pick it up.

Thanks Peter. I posted the v4 patchset yesterday to fix the defect of
Sashiko. Please pick up the v4 version. Here is the v4 patchset link. 

https://lore.kernel.org/all/20260616044654.3468742-1-dapeng1.mi@xxxxxxxxxxxxxxx/