Re: [PATCH] sched/fair: Reschedule the cfs_rq when current is ineligible

From: Mike Galbraith
Date: Sat May 25 2024 - 13:23:05 EST

On Sat, 2024-05-25 at 19:57 +0800, Chen Yu wrote:
>
> I suppose this change benefits the overloaded scenario:
> neither current nor the wakee is the best one.

Depends on your definition of benefit. It'll increasing ctx switches a
bit, but I recall it not being much.

I dug up the script I was using at the time, numbers below for the
bored. Bottom line: yeah, it's not much of a delta, especially when
comparing allegedly current EEVDF to CFS in an otherwise identical..
absolutely everything.

load: 5m chrome playing 1080p clip vs massive_intr (1 88% hog/cpu)

6.1.91-cfs
----------------------------------------------------------------------------------------------------------
Task | Runtime ms | Switches | Avg delay ms | Max delay ms | Sum delay ms |
----------------------------------------------------------------------------------------------------------
massive_intr:(9) |1897454.685 ms | 11581161 | avg: 0.026 ms | max: 43.008 ms | sum:296184.363 ms |
dav1d-worker:(8) | 94252.513 ms | 396284 | avg: 0.089 ms | max: 12.513 ms | sum:35275.546 ms |
Compositor:5824 | 36851.590 ms | 61771 | avg: 0.080 ms | max: 9.310 ms | sum: 4965.456 ms |
X:2362 | 32306.450 ms | 102571 | avg: 0.021 ms | max: 14.967 ms | sum: 2148.121 ms |
VizCompositorTh:5913 | 25116.956 ms | 56602 | avg: 0.053 ms | max: 8.441 ms | sum: 2986.101 ms |
chrome:(8) | 23134.386 ms | 85335 | avg: 0.052 ms | max: 34.540 ms | sum: 4459.871 ms |
ThreadPoolForeg:(43) | 16742.353 ms | 71410 | avg: 0.083 ms | max: 23.059 ms | sum: 5943.056 ms |
kwin_x11:2776 | 11383.572 ms | 95643 | avg: 0.017 ms | max: 8.358 ms | sum: 1589.414 ms |
VideoFrameCompo:5919 | 9589.949 ms | 37838 | avg: 0.029 ms | max: 6.842 ms | sum: 1098.123 ms |
kworker/5:1+eve:4508 | 8743.004 ms | 1647598 | avg: 0.003 ms | max: 12.002 ms | sum: 4956.587 ms |
kworker/6:2-mm_:5407 | 8686.689 ms | 1636766 | avg: 0.003 ms | max: 10.407 ms | sum: 4779.475 ms |
kworker/2:0-mm_:5707 | 8536.257 ms | 1607213 | avg: 0.003 ms | max: 9.473 ms | sum: 4776.918 ms |
kworker/4:1-mm_:379 | 8532.410 ms | 1603438 | avg: 0.003 ms | max: 10.328 ms | sum: 4824.572 ms |
kworker/1:0-eve:5409 | 8508.321 ms | 1598742 | avg: 0.003 ms | max: 13.124 ms | sum: 4742.128 ms |
perf:(2) | 5386.613 ms | 713 | avg: 0.020 ms | max: 2.268 ms | sum: 13.985 ms |
----------------------------------------------------------------------------------------------------------
TOTAL: |2242804.984 ms | 26015202 | | 43.008 ms | 416326.240 ms |
----------------------------------------------------------------------------------------------------------

6.1.91-eevdf
----------------------------------------------------------------------------------------------------------
Task | Runtime ms | Switches | Avg delay ms | Max delay ms | Sum delay ms |
----------------------------------------------------------------------------------------------------------
massive_intr:(9) |1971557.115 ms | 6127207 | avg: 0.034 ms | max: 16.351 ms | sum:208289.732 ms |
dav1d-worker:(8) | 85561.180 ms | 499175 | avg: 0.262 ms | max: 15.656 ms | sum:130584.659 ms |
Compositor:4346 | 37730.564 ms | 200925 | avg: 0.112 ms | max: 10.922 ms | sum:22406.729 ms |
X:2379 | 31761.636 ms | 229381 | avg: 0.081 ms | max: 9.740 ms | sum:18645.752 ms |
VizCompositorTh:4423 | 24650.743 ms | 155138 | avg: 0.170 ms | max: 11.227 ms | sum:26426.655 ms |
chrome:(8) | 19551.099 ms | 156680 | avg: 0.201 ms | max: 18.183 ms | sum:31449.401 ms |
ThreadPoolForeg:(43) | 15547.777 ms | 89292 | avg: 0.223 ms | max: 20.007 ms | sum:19916.046 ms |
kwin_x11:2776 | 11052.045 ms | 119945 | avg: 0.122 ms | max: 12.757 ms | sum:14687.478 ms |
VideoFrameCompo:4429 | 8794.874 ms | 76728 | avg: 0.142 ms | max: 10.183 ms | sum:10895.692 ms |
Chrome_ChildIOT:(7) | 4917.764 ms | 165906 | avg: 0.190 ms | max: 10.212 ms | sum:31461.521 ms |
Media:4428 | 3787.952 ms | 65288 | avg: 0.194 ms | max: 12.048 ms | sum:12662.386 ms |
kworker/6:1-eve:135 | 3359.276 ms | 616547 | avg: 0.009 ms | max: 7.999 ms | sum: 5762.212 ms |
kworker/4:1-eve:365 | 3144.292 ms | 578287 | avg: 0.009 ms | max: 7.619 ms | sum: 5322.637 ms |
kworker/3:2-eve:297 | 3104.034 ms | 557150 | avg: 0.013 ms | max: 8.006 ms | sum: 7050.461 ms |
perf:(2) | 3098.480 ms | 1585 | avg: 0.102 ms | max: 5.470 ms | sum: 160.995 ms |
----------------------------------------------------------------------------------------------------------
TOTAL: |2271694.585 ms | 16259483 | | 32.144 ms | 669428.151 ms |
----------------------------------------------------------------------------------------------------------

+tweak
----------------------------------------------------------------------------------------------------------
Task | Runtime ms | Switches | Avg delay ms | Max delay ms | Sum delay ms |
----------------------------------------------------------------------------------------------------------
massive_intr:(9) |1965603.161 ms | 6284089 | avg: 0.034 ms | max: 16.005 ms | sum:214120.602 ms |
dav1d-worker:(8) | 89853.413 ms | 599733 | avg: 0.240 ms | max: 48.387 ms | sum:144117.080 ms |
Compositor:4342 | 36473.771 ms | 171986 | avg: 0.129 ms | max: 11.366 ms | sum:22135.405 ms |
X:2365 | 32167.915 ms | 218157 | avg: 0.088 ms | max: 9.841 ms | sum:19105.816 ms |
VizCompositorTh:4425 | 24338.749 ms | 151884 | avg: 0.181 ms | max: 11.755 ms | sum:27553.783 ms |
chrome:(8) | 20154.023 ms | 158554 | avg: 0.207 ms | max: 15.979 ms | sum:32742.291 ms |
ThreadPoolForeg:(45) | 15672.931 ms | 94051 | avg: 0.215 ms | max: 17.452 ms | sum:20185.561 ms |
kwin_x11:2773 | 11424.789 ms | 121491 | avg: 0.140 ms | max: 11.116 ms | sum:16958.020 ms |
VideoFrameCompo:4431 | 8869.431 ms | 82385 | avg: 0.139 ms | max: 10.906 ms | sum:11471.193 ms |
Chrome_ChildIOT:(7) | 5148.973 ms | 167824 | avg: 0.189 ms | max: 13.755 ms | sum:31640.759 ms |
kworker/7:1-eve:86 | 4258.124 ms | 784269 | avg: 0.009 ms | max: 8.228 ms | sum: 6780.999 ms |
Media:4430 | 3897.705 ms | 62985 | avg: 0.205 ms | max: 10.797 ms | sum:12904.412 ms |
kworker/6:1-eve:189 | 3608.493 ms | 663349 | avg: 0.009 ms | max: 7.902 ms | sum: 6034.231 ms |
kworker/5:2-eve:827 | 3309.865 ms | 611424 | avg: 0.009 ms | max: 7.112 ms | sum: 5552.591 ms |
perf:(2) | 3241.897 ms | 1847 | avg: 0.087 ms | max: 5.464 ms | sum: 160.383 ms |
----------------------------------------------------------------------------------------------------------
TOTAL: |2272683.607 ms | 16721925 | | 57.181 ms | 692810.431 ms |
----------------------------------------------------------------------------------------------------------
hohum
+peterz queue w. RUN_TO_PARITY
----------------------------------------------------------------------------------------------------------
Task | Runtime ms | Switches | Avg delay ms | Max delay ms | Sum delay ms |
----------------------------------------------------------------------------------------------------------
massive_intr:(9) |1972481.970 ms | 4989513 | avg: 0.042 ms | max: 20.019 ms | sum:208651.087 ms |
dav1d-worker:(8) | 85235.372 ms | 528422 | avg: 0.254 ms | max: 15.253 ms | sum:134274.493 ms |
Compositor:4343 | 36977.626 ms | 154214 | avg: 0.122 ms | max: 9.868 ms | sum:18854.543 ms |
X:2359 | 31873.877 ms | 187392 | avg: 0.094 ms | max: 10.100 ms | sum:17644.947 ms |
VizCompositorTh:4427 | 24881.223 ms | 120412 | avg: 0.176 ms | max: 14.813 ms | sum:21210.898 ms |
chrome:(8) | 21579.151 ms | 133086 | avg: 0.200 ms | max: 12.952 ms | sum:26600.419 ms |
ThreadPoolForeg:(45) | 15327.978 ms | 94395 | avg: 0.196 ms | max: 35.000 ms | sum:18547.639 ms |
kwin_x11:2776 | 11232.090 ms | 121392 | avg: 0.135 ms | max: 10.313 ms | sum:16426.213 ms |
VideoFrameCompo:4433 | 8858.806 ms | 65658 | avg: 0.144 ms | max: 11.409 ms | sum: 9485.191 ms |
Chrome_ChildIOT:(7) | 4970.611 ms | 172570 | avg: 0.142 ms | max: 11.008 ms | sum:24467.160 ms |
Media:4432 | 3781.277 ms | 63640 | avg: 0.162 ms | max: 10.096 ms | sum:10283.264 ms |
kworker/7:1-eve:91 | 2930.823 ms | 534857 | avg: 0.009 ms | max: 8.234 ms | sum: 4723.577 ms |
kworker/6:2-eve:356 | 2579.393 ms | 472864 | avg: 0.009 ms | max: 8.046 ms | sum: 4148.828 ms |
perf:(2) | 2569.531 ms | 1609 | avg: 0.101 ms | max: 5.966 ms | sum: 163.224 ms |
kworker/4:0-eve:40 | 2432.133 ms | 442300 | avg: 0.009 ms | max: 9.475 ms | sum: 3992.979 ms |
----------------------------------------------------------------------------------------------------------
TOTAL: |2263072.188 ms | 12993836 | | 35.000 ms | 601609.374 ms |
----------------------------------------------------------------------------------------------------------
marko?
+NO_DELAY_DEQUEUE
----------------------------------------------------------------------------------------------------------
Task | Runtime ms | Switches | Avg delay ms | Max delay ms | Sum delay ms |
----------------------------------------------------------------------------------------------------------
massive_intr:(9) |1968212.427 ms | 6050894 | avg: 0.035 ms | max: 20.032 ms | sum:213163.997 ms |
dav1d-worker:(8) | 86929.255 ms | 583692 | avg: 0.246 ms | max: 14.986 ms | sum:143561.571 ms |
Compositor:4933 | 36733.711 ms | 219265 | avg: 0.100 ms | max: 14.986 ms | sum:21888.378 ms |
X:2359 | 31624.338 ms | 233581 | avg: 0.074 ms | max: 8.629 ms | sum:17324.762 ms |
VizCompositorTh:5018 | 24597.941 ms | 179049 | avg: 0.147 ms | max: 11.717 ms | sum:26333.576 ms |
chrome:(8) | 20430.046 ms | 179393 | avg: 0.173 ms | max: 20.903 ms | sum:30976.208 ms |
ThreadPoolForeg:(39) | 15423.142 ms | 109837 | avg: 0.183 ms | max: 24.525 ms | sum:20115.906 ms |
kwin_x11:2776 | 11413.866 ms | 129426 | avg: 0.121 ms | max: 10.718 ms | sum:15719.900 ms |
VideoFrameCompo:5023 | 8817.956 ms | 78028 | avg: 0.130 ms | max: 18.471 ms | sum:10162.602 ms |
Chrome_ChildIOT:(7) | 5356.461 ms | 187001 | avg: 0.160 ms | max: 11.565 ms | sum:29969.033 ms |
Media:5022 | 3793.341 ms | 64887 | avg: 0.186 ms | max: 13.229 ms | sum:12096.948 ms |
kworker/6:0-eve:5052 | 3509.228 ms | 643562 | avg: 0.010 ms | max: 8.005 ms | sum: 6305.605 ms |
kworker/3:0-eve:34 | 3363.538 ms | 598417 | avg: 0.012 ms | max: 8.892 ms | sum: 6910.297 ms |
perf:(2) | 3167.463 ms | 1835 | avg: 0.090 ms | max: 5.039 ms | sum: 164.352 ms |
kworker/4:2+eve:4808 | 3002.682 ms | 549210 | avg: 0.010 ms | max: 8.622 ms | sum: 5400.444 ms |
----------------------------------------------------------------------------------------------------------
TOTAL: |2270484.307 ms | 16315986 | | 24.525 ms | 677870.230 ms |
----------------------------------------------------------------------------------------------------------
polo