Messages in this thread | | | Date | Mon, 13 Jan 2020 13:29:11 +0100 | From | Peter Zijlstra <> | Subject | Re: [PATCH RFC] sched/fair: Penalty the cfs task which executes mwait/hlt |
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On Mon, Jan 13, 2020 at 12:18:46PM +0100, Rafael J. Wysocki wrote: > On Monday, January 13, 2020 11:43:14 AM CET Peter Zijlstra wrote:
> > Anyone, what will it take to get MPERF/TSC 'working' ? > > The same thing that intel_pstate does.
But intel_pstate cheats, it has a FMS listing and possible 'interesting' chips are excluded. For instance, Core2 has APERF/MPERF, but intel_pstate does not support Core2.
Simlarly, intel_pstate does (obviously) not support AMD chips, even tho those have APERF/MPERF.
Although I suppose Core2 doesn't have VMX and is therefore less interesting, but then we'd need to gate the logic with something like:
static_cpu_has(X86_FEATURE_APERFMPERF) && (static_cpu_has(X86_FEATURE_VMX) || static_cpu_has(X86_FEATURE_SVM)
> Generally speaking, it shifts the mperf values by a number of positions > depending on the CPU model, but that is 1 except for KNL. > > See get_target_pstate().
I'm going to go out on a limb and guess that's the same KNL hack as TurboStat has.
Is that really the only known case?
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