[igt-dev] [PATCH i-g-t 1/3] tests/perf_pmu: Tighten busy measurement

[Tvrtko Ursulin]

On 01/02/2018 17:08, Chris Wilson wrote:
> Quoting Tvrtko Ursulin (2018-02-01 16:58:21)
>>
>> I am just moving the two sample read-outs closer together in time. Two
>> samples are measure of how long we slept, and measure of PMU busyness.
>> There should be as little time as possible between the two readouts.
>> Ending the spinner I don't see how it belongs in this sandwich, or
>> anything else really.
> 
> Then we disagree on what we think we are measuring. The usleep should
> equal the busy value defined by the spin-batch.

I agree, and that is why there should be no extra work between the sleep 
ending and PMU read-out.

Sleep is defining the spin-batch duration and that is the most accurate 
value for it we got.

Regards,

Tvrtko