Re: [patch] sched: disable task group re-weighting on the desktop

From: Peter Zijlstra
Date: Sat Oct 10 2015 - 13:01:52 EST


On Sat, Oct 10, 2015 at 03:22:49PM +0200, Mike Galbraith wrote:
> Ah, but now onward to interactivity...
>
> master, 8 groups of 1 (pert) vs desktop (mplayer BigBuckBunny-DivXPlusHD.mkv)
> PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ P COMMAND
> 4068 root 20 0 8312 724 628 R 99.64 0.004 1:04.32 6 pert
> 4065 root 20 0 8312 744 648 R 99.45 0.005 1:04.92 5 pert
> 4071 root 20 0 8312 748 652 R 99.27 0.005 1:03.12 7 pert
> 4077 root 20 0 8312 840 744 R 98.72 0.005 1:01.46 3 pert
> 4074 root 20 0 8312 796 700 R 98.18 0.005 1:03.38 1 pert
> 4079 root 20 0 8312 720 624 R 97.99 0.004 1:01.45 4 pert
> 4062 root 20 0 8312 836 740 R 96.72 0.005 1:03.44 0 pert
> 4059 root 20 0 8312 720 624 R 94.16 0.004 1:04.92 2 pert
> 4082 root 20 0 1094400 154324 33592 S 4.197 0.954 0:02.69 0 mplayer
> 1029 root 20 0 465332 151540 40816 R 3.285 0.937 0:24.59 2 Xorg
> 1773 root 20 0 662592 73308 42012 S 2.007 0.453 0:12.84 5 konsole
> 771 root 20 0 11416 1964 1824 S 0.730 0.012 0:10.45 0 rngd
> 1722 root 20 0 2866772 65224 51152 S 0.365 0.403 0:03.44 2 kwin
> 1769 root 20 0 711684 54212 38020 S 0.182 0.335 0:00.39 1 kmix
>
> That is NOT good. Mplayer and friends need more than that. Interactivity
> is _horrible_, and buck is an unwatchable mess (no biggy, I know every frame).
>
> master+, 8 groups of 1 (pert) vs desktop (mplayer BigBuckBunny-DivXPlusHD.mkv)
> PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ P COMMAND
> 4346 root 20 0 8312 756 660 R 99.20 0.005 0:59.89 5 pert
> 4349 root 20 0 8312 748 652 R 98.80 0.005 1:00.77 6 pert
> 4343 root 20 0 8312 720 624 R 94.81 0.004 1:02.11 2 pert
> 4331 root 20 0 8312 724 628 R 91.22 0.004 1:01.16 3 pert
> 4340 root 20 0 8312 720 624 R 91.22 0.004 1:01.06 7 pert
> 4328 root 20 0 8312 836 740 R 90.42 0.005 1:00.07 4 pert
> 4334 root 20 0 8312 756 660 R 87.82 0.005 0:59.84 1 pert
> 4337 root 20 0 8312 824 728 R 76.85 0.005 0:52.20 0 pert
> 4352 root 20 0 1058812 123876 33388 S 29.34 0.766 0:25.01 3 mplayer
> 1029 root 20 0 471168 156748 40316 R 22.36 0.969 0:42.23 3 Xorg
> 1773 root 20 0 663080 74176 42012 S 4.192 0.459 0:17.98 1 konsole
> 771 root 20 0 11416 1964 1824 R 1.198 0.012 0:13.45 0 rngd
> 1722 root 20 0 2866880 65340 51152 R 0.599 0.404 0:04.87 3 kwin
> 1788 root 9 -11 516744 11932 8536 S 0.599 0.074 0:01.01 0 pulseaudio
> 1733 root 20 0 3369480 141564 71776 S 0.200 0.875 0:05.51 1 plasma-desktop
>
> That's good. Interactivity is fine...

But the patch is most horrible.. :/ It completely destroys everything
group scheduling is supposed to be.

What are these oink/pert things? Both spinners just with amusing names
to distinguish them?

Is the interactivity the same (horrible) at fe32d3cd5e8e (ie, before the
load tracking rewrite from Yuyang)?
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