On 13/01/20 11:43, Peter Zijlstra wrote:
> So the very first thing we need to get sorted is that MPERF/TSC ratio
> thing. TurboStat does it, but has 'funny' hacks on like:
>
> b2b34dfe4d9a ("tools/power turbostat: KNL workaround for %Busy and Avg_MHz")
>
> and I imagine that there's going to be more exceptions there. You're
> basically going to have to get both Intel and AMD to commit to this.
>
> IFF we can get concensus on MPERF/TSC, then yes, that is a reasonable
> way to detect a VCPU being idle I suppose. I've added a bunch of people
> who seem to know about this.
>
> Anyone, what will it take to get MPERF/TSC 'working' ?
Do we really need MPERF/TSC for this use case, or can we just track
APERF as well and do MPERF/APERF to compute the "non-idle" time?
Paolo
