[Intel-gfx] [RFC v2 2/3] drm/i915/pmu: serve global events and support perf stat

[Peter Zijlstra]

On Wed, Aug 30, 2017 at 05:24:30PM +0000, Rogozhkin, Dmitry V wrote:
> I figured out how to track cpus online/offline status in PMU. Here is a
> question however. What is the reason for uncore PMUs (cstate.c for
> example) to register for cpus other than cpu0? I see it registers for
> first thread of each cpu, on my 8 logical-core systems it registers for
> cpu0-3 it seems.

The other answer is that on multi-socket, C-state needs more than 1 CPU.