Messages in this thread | | | Subject | Re: [PATCH] cpufreq: intel_pstate: Optimize IO boost in non HWP mode | From | Srinivas Pandruvada <> | Date | Mon, 03 Sep 2018 08:15:31 -0700 |
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On Mon, 2018-09-03 at 18:10 +0300, Eero Tamminen wrote: > Hi, > > On 31.08.2018 20:28, Srinivas Pandruvada wrote: > ... > > As per testing Eero Tamminen, the results are comparable to the > > patchset > > https://patchwork.kernel.org/patch/10312259/ > > But he has to watch results for several days to check trend. > > It's close, but there is some gap compared to Francisco's version. > > (Because of the large variance on TDP limited devices, and factors > causing extra perf differences e.g. between boots, it's hard to give > exact number without having trends from several days / weeks. I > would > also need new version of Fransisco's patch set that applies to > latest > kernel like yours does.) > > > > Since here boost is getting limited to turbo and non turbo, we need > > some > > ways to adjust the fractions corresponding to max non turbo as > > well. It > > is much easier to use the actual P-state limits for boost instead > > of > > fractions. So here P-state io boost limit is applied on top of the > > P-state limit calculated via current algorithm by removing current > > io_wait boost calculation using fractions. > > > > Since we prefer to use common algorithm for all processor > > platforms, this > > change was tested on other client and sever platforms as well. All > > results > > were within the margin of errors. Results: > > https://bugzilla.kernel.org/attachment.cgi?id=278149 > > Good. > > Francisco, how well the listed PTS tests cover latency bound cases > you > were concerned about? [1] > > > - Eero > > [1] Fransisco was concerned that the patch: > * trade-off might regress latency bound cases (which I haven't > tested, I > tested only 3D throughput), and > * that it addressed only other of the sources of energy > inefficiencies > he had identified (which could explain slightly better 3D results > from > his more complex patch set). It is always possible to submit improvement patch later. Atleast this patch will reduce the usage of turbo.
Thanks, Srinivas
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