Re: [PATCH 05/19] sched/numa: Use task faults only if numa_group is not yet setup

Srikar Dronamraju
2018-06-04T13:10:42Z

> > Testcase Time: Min Max Avg StdDev %Change
> > numa01.sh Real: 478.45 565.90 515.11 30.87 16.29%
> > numa01.sh Sys: 207.79 271.04 232.94 21.33 -15.8%
> > numa01.sh User: 39763.93 47303.12 43210.73 2644.86 14.04%
> > numa02.sh Real: 60.00 61.46 60.78 0.49 0.871%
> > numa02.sh Sys: 15.71 25.31 20.69 3.42 17.35%
> > numa02.sh User: 5175.92 5265.86 5235.97 32.82 0.464%
> > numa03.sh Real: 776.42 834.85 806.01 23.22 -7.47%
> > numa03.sh Sys: 114.43 128.75 121.65 5.49 -19.5%
> > numa03.sh User: 60773.93 64855.25 62616.91 1576.39 -5.36%
> > numa04.sh Real: 456.93 511.95 482.91 20.88 2.930%
> > numa04.sh Sys: 178.09 460.89 356.86 94.58 -11.3%
> > numa04.sh User: 36312.09 42553.24 39623.21 2247.96 0.246%
> > numa05.sh Real: 393.98 493.48 436.61 35.59 0.677%
> > numa05.sh Sys: 164.49 329.15 265.87 61.78 38.92%
> > numa05.sh User: 33182.65 36654.53 35074.51 1187.71 3.368%
> >
> > Ideally this change shouldn't have affected performance.
>
> Ideally you go on here to explain why it does in fact do affect
> performance.. :-)

I know it looks bad, but I have been unable to figure out why this patch
affects performance. I repeated the experiment multiple times to recheck
if it was not a one off problem. While there is a variance in different
runs, we do see a change in numbers before and after this patch atleast
on my machine.