Re: [PATCH 6/6] cpufreq: schedutil: New governor based on scheduler utilization data

Steve Muckle
2016-03-03T21:37:59Z

On 03/03/2016 12:20 PM, Rafael J. Wysocki wrote:
>> Here is a comparison, with frequency invariance, of ondemand and
>> interactive with schedfreq and schedutil. The first two columns (run and
>> period) are omitted so the table will fit.
>>
>> ondemand interactive schedfreq schedutil
>> busy % OR OH OR OH OR OH OR OH
>> 1.00% 0 68.96% 0 100.04% 0 78.49% 0 95.86%
>> 1.00% 0 25.04% 0 22.59% 0 72.56% 0 71.61%
>> 10.00% 0 21.75% 0 63.08% 0 52.40% 0 41.78%
>> 10.00% 0 12.17% 0 14.41% 0 17.33% 0 47.96%
>> 10.00% 0 2.57% 0 2.17% 0 0.29% 0 26.03%
>> 18.18% 0 12.39% 0 9.39% 0 17.34% 0 31.61%
>> 19.82% 0 3.74% 0 3.42% 0 12.26% 0 29.46%
>> 40.00% 2 6.26% 1 12.23% 0 6.15% 0 12.93%
>> 40.00% 0 0.47% 0 0.05% 0 2.68% 2 14.08%
>> 40.00% 0 0.60% 0 0.50% 0 1.22% 0 11.58%
>> 55.56% 2 4.25% 5 5.97% 0 2.51% 0 7.70%
>> 55.56% 0 1.89% 0 0.04% 0 1.71% 6 8.06%
>> 55.56% 0 0.50% 0 0.47% 0 1.82% 5 6.94%
>> 75.00% 2 1.65% 1 0.46% 0 0.26% 56 3.59%
>> 75.00% 0 1.68% 0 0.05% 0 0.49% 21 3.94%
>> 75.00% 0 0.28% 0 0.23% 0 0.62% 4 4.41%
>>
>> Aside from the 2nd and 3rd tests schedutil is showing decreased
>> performance across the board. The fifth test is particularly bad.
>
> I guess you mean performance in terms of the overhead?

Correct. This overhead metric describes how fast the workload completes,
with 0% equaling the perf governor and 100% equaling the powersave
governor. So it's a reflection of general performance using the
governor. It's called "overhead" I imagine (the metric predates my
involvement) as it is something introduced/caused by the policy of the
governor.

thanks,
Steve