Messages in this thread | | | From | "Rafael J. Wysocki" <> | Date | Tue, 17 Jul 2018 17:29:21 +0200 | Subject | Re: Commit 554c8aa8ecad causing severe performance degression with pcc-cpufreq |
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On Tue, Jul 17, 2018 at 4:03 PM, Andreas Herrmann <aherrmann@suse.com> wrote: > On Tue, Jul 17, 2018 at 12:21:36PM +0200, Andreas Herrmann wrote: >> On Tue, Jul 17, 2018 at 12:09:21PM +0200, Rafael J. Wysocki wrote: > > ---8<--- > >> > OK, the patch is below. >> > >> > First, I hope that if "Collaborative Power Control" is disabled, it will >> > simply hide the PCCH object and so intel_pstate will still not load then. >> >> PCCH is hidden in that case. >> >> > The main question basically is what the OS is expected to do if >> > "Dynamic Power Savings Mode" is set. If we are *expected* to use >> > the PCC interface then, intel_pstate may not work in that case, but >> > I suspect that the PCC interface allows extra energy to be saved >> > over what is possible without it. >> >> I'll test it and see what happens. > > I've tested it on top of v4.18-rc5-36-g30b06abfb92b. intel_pstate now > loads instead of pcc-cpufreq and system looks stable. > > When disabling "Collaborative Power Control" no cpufreq driver is loaded > (as expected). > > Performance (with kernbench) is as expected (always better than any > brew of pcc-cpufreq + misc modifications to this driver + partial > rollback of commit 554c8aa8ecad). > > If you like you can add either Tested-by or > Reviewed-by: Andreas Herrmann <aherrmann@suse.com> > > I think this patch should be tagged for 4.17-stable.
OK, thank you for testing!
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