linux-kernel - Re: [PATCH V3 1/3] perf/x86: Add new event for AUX output counter index

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Message-ID: <3211feb9-b8e3-21fc-958c-07c7c7766bf2@intel.com>
Date:   Wed, 13 Oct 2021 12:12:48 +0300
From:   Adrian Hunter <adrian.hunter@...el.com>
To:     Alexander Shishkin <alexander.shishkin@...ux.intel.com>,
        "Liang, Kan" <kan.liang@...ux.intel.com>,
        Peter Zijlstra <peterz@...radead.org>
Cc:     Ingo Molnar <mingo@...hat.com>,
        Arnaldo Carvalho de Melo <acme@...nel.org>,
        Mark Rutland <mark.rutland@....com>,
        Jiri Olsa <jolsa@...hat.com>, Leo Yan <leo.yan@...aro.org>,
        x86@...nel.org, linux-perf-users@...r.kernel.org,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH V3 1/3] perf/x86: Add new event for AUX output counter
 index

On 23/09/2021 22:22, Alexander Shishkin wrote:
> Adrian Hunter <adrian.hunter@...el.com> writes:
> 
>> On 10/09/21 7:29 pm, Liang, Kan wrote:
>>>
>>>
>>> On 9/10/2021 12:04 PM, Peter Zijlstra wrote:
>>>> On Tue, Sep 07, 2021 at 01:45:22PM -0400, Liang, Kan wrote:
>>>>> On 9/7/2021 12:39 PM, Adrian Hunter wrote:
>>>>
>>>>>> @@ -4494,8 +4500,16 @@ static int intel_pmu_check_period(struct perf_event *event, u64 value)
>>>>>>        return intel_pmu_has_bts_period(event, value) ? -EINVAL : 0;
>>>>>>    }
>>>>>> +static void intel_aux_output_init(void)
>>>>>> +{
>>>>>> +    /* Refer also intel_pmu_aux_output_match() */
>>>>>> +    if (x86_pmu.intel_cap.pebs_output_pt_available)
>>>>>> +        x86_pmu.assign = intel_pmu_assign_event;
>>>>>> +}
>>>>>
>>>>> For a hybrid machine, x86_pmu.intel_cap.pebs_output_pt_available is always
>>>>> cleared. We probably need the PMU specific
>>>>> pmu->intel_cap.pebs_output_pt_available here.
>>>>>
>>>>>> +
>>>>>>    static int intel_pmu_aux_output_match(struct perf_event *event)
>>>>>>    {
>>>>>> +    /* intel_pmu_assign_event() is needed, refer intel_aux_output_init() */
>>>>>>        if (!x86_pmu.intel_cap.pebs_output_pt_available)
>>>>>>            return 0;
>>>>>>
>>>>>
>>>>> For a hybrid machine, this always return 0. I think we need to fix it first?
>>>>
>>>> AFAICT the patch is correct for !hybrid, and the hybrid PT muck can then
>>>> also fix this up, right?
>>>>
>>>
>>> Yes, for !hybrid, the patch is good.
>>>
>>> Since PEBS via PT is temporarily disabled for hybrid for now, the patch set should not bring any issues with hybrid either.
>>> The hybrid PT can be fixed separately.
>>
>> I don't have much time to look at the hybrid case right now.
>>
>> Would it be OK to go ahead with these patches?
> 
> I'll deal with the PEBS-via-PT on hybrid. As it stands right now, this
> patchset is good.

Will anyone takes these patches?  Perhaps Arnaldo if no one objects?
The patches still seem to apply cleanly.