Re: [PATCH V2 0/3] Support auto counter reload

[Ingo Molnar]

* kan.liang@xxxxxxxxxxxxxxx <kan.liang@xxxxxxxxxxxxxxx> wrote:

> From: Kan Liang <kan.liang@xxxxxxxxxxxxxxx>
> 
> Changes since V1:
> - Add a check to the reload value which cannot exceeds the max period
> - Avoid invoking intel_pmu_enable_acr() for the perf metrics event.
> - Update comments explain to case which the event->attr.config2 exceeds
>   the group size

> The 2498 samples are all from the branch-misses events for the Loop 2.
> 
> The number of samples and overhead is significantly reduced without
> losing any information.

Ok, that looks like a pretty sweet PMU feature.

What is the hardware support range of this auto count reload feature, 
how recent CPU does one have to have?

The series has aged a bit though, while a variant of patch #1 has been 
merged already under:

  47a973fd7563 perf/x86/intel: Fix ARCH_PERFMON_NUM_COUNTER_LEAF

... but #2 and #3 don't apply cleanly anymore.

Mind sending a refreshed series perhaps?

Thanks,

	Ingo