Messages in this thread | | | Subject | Re: default cpufreq gov, was: [PATCH] sched/fair: check for idle core | From | Tom Lendacky <> | Date | Fri, 23 Oct 2020 12:46:35 -0500 |
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On 10/23/20 2:03 AM, Peter Zijlstra wrote: > On Thu, Oct 22, 2020 at 10:10:35PM +0200, Giovanni Gherdovich wrote: >> * for the AMD EPYC machines we haven't yet implemented frequency invariant >> accounting, which might explain why schedutil looses to ondemand on all >> the benchmarks. > > Right, I poked the AMD people on that a few times, but nothing seems to > be forthcoming :/ Tom, any way you could perhaps expedite the matter?
Adding Nathan to the thread to help out here.
Thanks, Tom
> > In particular we're looking for some X86_VENDOR_AMD/HYGON code to run in > > arch/x86/kernel/smpboot.c:init_freq_invariance() > > The main issue is finding a 'max' frequency that is not the absolute max > turbo boost (this could result in not reaching it very often) but also > not too low such that we're always clipping. > > And while we're here, IIUC AMD is still using acpi_cpufreq, but AFAIK > the chips have a CPPC interface which could be used instead. Is there > any progress on that? >
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