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

["Mi, Dapeng" <dapeng1.mi@linux.intel.com>]

On 6/17/2026 8:14 AM, Mi, Dapeng wrote:
> 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@linux.intel.com/

Hi Peter,

Could you please queue above latest v4 patchset
(https://lore.kernel.org/all/20260616044654.3468742-1-dapeng1.mi@linux.intel.com/)
which fixes a defect in patch 5/8  "perf/x86/intel: Validate the return
value of intel_pmu_init_hybrid()"? 

Besides this change, all changes of v4 are same with this v3 patchset? 

Thanks!


>
>
>