Re: HT (Hyper Threading) aware process scheduling doesn't work as it should

From: Con Kolivas
Date: Mon Oct 31 2011 - 06:17:34 EST


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

Regards,
Con Kolivas

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