On Fri, 2017-12-15 at 21:23 +0100, Mike Galbraith wrote: > > Point: if you think it's OK to serialize these firefox threads, would > you still think so if those were kernel threads instead? Serializing > your kernel is a clear fail, but unpinned kthreads can be stacked up > just as effectively as those browser threads are, eat needless wakeup > latency and pass it on.
FWIW, somewhat cheezy example of that below. (later, /me returns to [apparently endless] squabble w. PELT/SIS;) bonnie in nfs mount of own box competing with 7 hogs: ------------------------------------------------------------------------------------------------------------------------------------ Task | Runtime ms | Switches | Average delay ms | Maximum delay ms | Sum delay ms | Maximum delay at | ------------------------------------------------------------------------------------------------------------------------------------ kworker/3:0:29 | 630.078 ms | 89669 | avg: 0.011 ms | max: 102.340 ms | sum: 962.919 ms | max at: 310.501277 | kworker/3:1H:464 | 1179.868 ms | 101944 | avg: 0.005 ms | max: 102.232 ms | sum: 480.915 ms | max at: 310.501273 | kswapd0:78 | 2662.230 ms | 1661 | avg: 0.128 ms | max: 93.935 ms | sum: 213.258 ms | max at: 310.503419 | nfsd:2039 | 3257.143 ms | 78448 | avg: 0.112 ms | max: 86.039 ms | sum: 8795.767 ms | max at: 258.847140 | nfsd:2038 | 3185.730 ms | 76253 | avg: 0.113 ms | max: 78.348 ms | sum: 8580.676 ms | max at: 258.831370 | nfsd:2042 | 3256.554 ms | 81423 | avg: 0.110 ms | max: 74.941 ms | sum: 8929.015 ms | max at: 288.397203 | nfsd:2040 | 3314.826 ms | 80396 | avg: 0.105 ms | max: 51.039 ms | sum: 8471.816 ms | max at: 363.870078 | nfsd:2036 | 3058.867 ms | 70460 | avg: 0.115 ms | max: 44.629 ms | sum: 8092.319 ms | max at: 250.074253 | nfsd:2037 | 3113.592 ms | 74276 | avg: 0.115 ms | max: 43.294 ms | sum: 8556.110 ms | max at: 310.443722 | konsole:4013 | 402.509 ms | 894 | avg: 0.148 ms | max: 38.129 ms | sum: 132.050 ms | max at: 332.156495 | haveged:497 | 11.831 ms | 1224 | avg: 0.104 ms | max: 37.575 ms | sum: 127.706 ms | max at: 350.669645 | nfsd:2043 | 3316.033 ms | 78303 | avg: 0.115 ms | max: 36.511 ms | sum: 8995.138 ms | max at: 248.576108 | nfsd:2035 | 3064.108 ms | 67413 | avg: 0.115 ms | max: 28.221 ms | sum: 7746.306 ms | max at: 313.785682 | bash:7022 | 0.342 ms | 1 | avg: 22.959 ms | max: 22.959 ms | sum: 22.959 ms | max at: 262.258960 | kworker/u16:4:354 | 2073.383 ms | 1550 | avg: 0.050 ms | max: 21.203 ms | sum: 77.185 ms | max at: 332.220678 | kworker/4:3:6975 | 1189.868 ms | 115776 | avg: 0.018 ms | max: 20.856 ms | sum: 2071.894 ms | max at: 348.142757 | kworker/2:4:6981 | 335.895 ms | 26617 | avg: 0.023 ms | max: 20.726 ms | sum: 625.102 ms | max at: 248.522083 | bash:7021 | 0.517 ms | 2 | avg: 10.363 ms | max: 20.726 ms | sum: 20.727 ms | max at: 262.235708 | ksoftirqd/2:22 | 65.718 ms | 998 | avg: 0.138 ms | max: 19.072 ms | sum: 137.827 ms | max at: 332.221676 | kworker/7:3:6969 | 625.724 ms | 84153 | avg: 0.010 ms | max: 18.838 ms | sum: 876.603 ms | max at: 264.188983 | bonnie:6965 | 79637.998 ms | 35434 | avg: 0.007 ms | max: 18.719 ms | sum: 256.748 ms | max at: 331.299867 |
