Messages in this thread | | | Subject | Re: HT (Hyper Threading) aware process scheduling doesn't work as it should | From | Mike Galbraith <> | Date | Mon, 31 Oct 2011 12:42:28 +0100 |
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On Mon, 2011-10-31 at 21:06 +1100, Con Kolivas wrote: > On Sun, 30 Oct 2011 07:57:12 PM Artem S. Tashkinov wrote: > > I've found out that even on Linux 3.0.8 the process scheduler doesn't > > correctly distributes the load amongst virtual CPUs. E.g. on a 4-core > > system (8 total virtual CPUs) the process scheduler often run some > > instances of four different tasks on the same physical CPU. > > > Any thoughts? comments? I think this is quite a serious problem. > > Intense cache locality logic, power saving concepts, cpu frequency governor > behaviour and separate runqueues per CPU within the current CPU process > scheduler in the current mainline linux kernel will ocasionally do this. Some > workloads will be better, while others will be worse. Feel free to try my BFS > cpu scheduler if you wish a CPU process scheduler that spreads work more > evenly across CPUs. > > Alas the last version I synced up with will not apply cleanly past about 3.0.6 > I believe: > > http://ck.kolivas.org/patches/bfs/3.0.0/3.0-sched-bfs-413.patch
Yeah, it handles independent tasks well, but cache misses can be excruciatingly painful for the others.
Q6600 box, configs as identical as possible, tbench 8
3.0.6-bfs413 728.6 MB/sec 3.0.8 1146.7 MB/sec
-Mike
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