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SubjectRe: [PATCH V5 16/25] perf/x86: Register hybrid PMUs
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On 4/9/2021 11:45 AM, Peter Zijlstra wrote:
> On Fri, Apr 09, 2021 at 09:50:20AM -0400, Liang, Kan wrote:
>>
>>
>> On 4/9/2021 2:58 AM, Peter Zijlstra wrote:
>>> On Mon, Apr 05, 2021 at 08:10:58AM -0700, kan.liang@linux.intel.com wrote:
>>>> @@ -2089,9 +2119,46 @@ static int __init init_hw_perf_events(void)
>>>> if (err)
>>>> goto out1;
>>>> - err = perf_pmu_register(&pmu, "cpu", PERF_TYPE_RAW);
>>>> - if (err)
>>>> - goto out2;
>>>> + if (!is_hybrid()) {
>>>> + err = perf_pmu_register(&pmu, "cpu", PERF_TYPE_RAW);
>>>> + if (err)
>>>> + goto out2;
>>>> + } else {
>>>> + u8 cpu_type = get_this_hybrid_cpu_type();
>>>> + struct x86_hybrid_pmu *hybrid_pmu;
>>>> + bool registered = false;
>>>> + int i;
>>>> +
>>>> + if (!cpu_type && x86_pmu.get_hybrid_cpu_type)
>>>> + cpu_type = x86_pmu.get_hybrid_cpu_type();
>>>> +
>>>> + for (i = 0; i < x86_pmu.num_hybrid_pmus; i++) {
>>>> + hybrid_pmu = &x86_pmu.hybrid_pmu[i];
>>>> +
>>>> + hybrid_pmu->pmu = pmu;
>>>> + hybrid_pmu->pmu.type = -1;
>>>> + hybrid_pmu->pmu.attr_update = x86_pmu.attr_update;
>>>> + hybrid_pmu->pmu.capabilities |= PERF_PMU_CAP_HETEROGENEOUS_CPUS;
>>>> +
>>>> + err = perf_pmu_register(&hybrid_pmu->pmu, hybrid_pmu->name,
>>>> + (hybrid_pmu->cpu_type == hybrid_big) ? PERF_TYPE_RAW : -1);
>>>> + if (err)
>>>> + continue;
>>>> +
>>>> + if (cpu_type == hybrid_pmu->cpu_type)
>>>> + x86_pmu_update_cpu_context(&hybrid_pmu->pmu, raw_smp_processor_id());
>>>> +
>>>> + registered = true;
>>>> + }
>>>> +
>>>> + if (!registered) {
>>>> + pr_warn("Failed to register hybrid PMUs\n");
>>>> + kfree(x86_pmu.hybrid_pmu);
>>>> + x86_pmu.hybrid_pmu = NULL;
>>>> + x86_pmu.num_hybrid_pmus = 0;
>>>> + goto out2;
>>>> + }
>>>
>>> I don't think this is quite right. registered will be true even if one
>>> fails, while I think you meant to only have it true when all (both)
>>> types registered correctly.
>>
>> No, I mean that perf error out only when all types fail to be registered.
>
> All or nothing seems a better approach to me. There really isn't a good
> reason for any one of them to fail.
>

Sure. I will change it in V6.

Thanks,
Kan

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