Messages in this thread | | | From | "Doug Smythies" <> | Subject | RE: [PATCH v4 1/6] x86,sched: Add support for frequency invariance | Date | Mon, 25 Nov 2019 21:59:19 -0800 |
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On 2019.11.25 08:06 Giovanni Gherdovich wrote: > On Sat, 2019-11-23 at 23:49 -0800, Doug Smythies wrote: >> ... >> Kernel 5.4-rc8 + revert, intel_cpufreq/schedutil: 3899 seconds >> Kernel 5.4-rc8 + gg 6 + revert, intel_cpufreq/schedutil: 2740.7 seconds >> Ratio: 0.70 (as expected) >> Kernel 5.4-rc8, intel_cpufreq/schedutil: 2334.7 seconds (faster than expected) >> Kernel 5.4-rc8 + gg 6 patch set, intel_cpufreq/schedutil: 2275.0 seconds (faster than expected) >> Ratio: 0.97 (not as expected) >> Kernel 5.4-rc8, intel_cpufreq/performance: 2215.3 seconds >> Kernel 5.4-rc8, intel_cpufreq/ondemand: 3286.3 seconds >> Re-stated from previous e-mail: >> Kernel 5.3-rc8, intel_cpufreq/schedutil: ratio: 0.69 (I don't have the original times) > > Hello Doug, > > schedutil in 5.4 going a lot faster than in 5.3 would be a surprise. I'm > running that same test too to check if I can see it as well.
Great, thanks. But see below.
> > Besides, as it's already been said this patchset adds frequency > scale-invariance to scheduler metrics such as load and utilization and that's > useful also in areas other than frequency scaling (most notably the scheduler > load balancer).
The issue with the schedutil governor not working properly in the 5.4 RC series appears to be hardware dependant.
My test computer is Intel(R) Core(TM) i7-2600K CPU @ 3.40GHz., Sandy Bridge. On a temporary basis, I acquired a computer with an Intel(R) Core(TM) i5-4460 CPU @ 3.20GHz, Haswell, and schedutil governor behaviour with the exact same kernels is fine:
That "gitsource" test, "make test" 6 times, first run thrown out:
Kernel 5.4 intel_cpufreq/schedutil: 3411.8 seconds Kernel 5.4 + gg 6 intel_cpufreq/schedutil: 1696.7 seconds Ratio: 0.49 Recall you got a ratio of 0.49 with 5th generation, Broadwell.
... Doug
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