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SubjectRe: [PATCH V4 1/5] perf/x86/intel: Fix event update for auto-reload
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On 2/21/2018 5:32 AM, Peter Zijlstra wrote:
> On Mon, Feb 12, 2018 at 02:20:31PM -0800, kan.liang@linux.intel.com wrote:
>> @@ -1389,8 +1456,22 @@ static void intel_pmu_drain_pebs_nhm(struct pt_regs *iregs)
>>
>> ds->pebs_index = ds->pebs_buffer_base;
>>
>> - if (unlikely(base >= top))
>> + if (unlikely(base >= top)) {
>> + /*
>> + * The drain_pebs() could be called twice in a short period
>> + * for auto-reload event in pmu::read(). There are no
>> + * overflows have happened in between.
>> + * It needs to call intel_pmu_save_and_restart_reload() to
>> + * update the event->count for this case.
>> + */
>> + for_each_set_bit(bit, (unsigned long *)&cpuc->pebs_enabled,
>> + x86_pmu.max_pebs_events) {
>> + event = cpuc->events[bit];
>> + if (event->hw.flags & PERF_X86_EVENT_AUTO_RELOAD)
>> + intel_pmu_save_and_restart_reload(event, 0);
>> + }
>> return;
>> + }
>>
>> for (at = base; at < top; at += x86_pmu.pebs_record_size) {
>> struct pebs_record_nhm *p = at;
>
> Is there a reason you didn't do intel_pmu_drain_pebs_core() ?
>

Right, I forgot that the drain_pebs_core() also has auto_reload support.
Sorry for that.
I will re-send all patches.

Thanks,
Kan

>
> --- a/arch/x86/events/intel/ds.c
> +++ b/arch/x86/events/intel/ds.c
> @@ -1435,8 +1435,11 @@ static void intel_pmu_drain_pebs_core(st
> return;
>
> n = top - at;
> - if (n <= 0)
> + if (n <= 0) {
> + if (event->hw.flags & PERF_X86_EVENT_AUTO_RELOAD)
> + intel_pmu_save_and_restart_reload(event, 0);
> return;
> + }
>
> __intel_pmu_pebs_event(event, iregs, at, top, 0, n);
> }
>

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