[Intel-gfx] [igt-dev] [CI i-g-t] tests/perf_pmu: Avoid RT thread for accuracy test
tvrtko.ursulin at linux.intel.com
Mon Mar 26 12:40:19 UTC 2018
On 26/03/2018 12:17, Chris Wilson wrote:
> Quoting Tvrtko Ursulin (2018-03-26 11:57:58)
>> * No self-adjust - instead just report the achieved cycle and let the
>> parent check against it.
> Sniff, I was rather proud of our achievement. I had it in mind as a
> template for future autocalibration routines. Is it really useless
> overengineering, or worse broken?
It works fine I think, but the problem is I cannot locate a source of
systematic error which seems proportional to number of loop iterations.
:( After battling with trying to improve it for a couple days I decided
to try to see how the simpler approach will fare on the shards.
There's the tasklet delay, which made me think things could be better
without RT. And then polling on the spinner makes it worse in all cases
for me, however I fiddle with it. So again, I wanted to try the
The version from this patch seems super stable on my system, but the 50%
case still has an apparent +.5-6% systematic error. Maybe on the shards
it will not be as stable..
More information about the Intel-gfx