Re: [PATCH v3 5/9] perf, x86: large PEBS interrupt threshold

From: Yan, Zheng
Date: Tue Jul 22 2014 - 20:59:13 EST


On 07/23/2014 12:16 AM, Andi Kleen wrote:
>> + /*
>> + * When the event is constrained enough we can use a larger
>> + * threshold and run the event with less frequent PMI.
>> + */
>> + if (0 && /* disable this temporarily */
>
> Where in the patchkit does it get reenabled?

enabled by patch 7
>
> -Andi
>
>> + (hwc->flags & PERF_X86_EVENT_AUTO_RELOAD) &&
>> + !(event->attr.sample_type & ~PEBS_FREERUNNING_FLAGS)) {
>> + threshold = ds->pebs_absolute_maximum -
>> + x86_pmu.max_pebs_events * x86_pmu.pebs_record_size;
>> + } else {
>> + threshold = ds->pebs_buffer_base + x86_pmu.pebs_record_size;
>> + }
>> + if (first_pebs || ds->pebs_interrupt_threshold > threshold)
>> + ds->pebs_interrupt_threshold = threshold;

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