Messages in this thread | | | Date | Wed, 14 Apr 1999 13:22:06 +0200 (CEST) | From | Rik van Riel <> | Subject | Re: CPU affinity |
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On Wed, 14 Apr 1999, Alan Cox wrote:
> > I am also doing video processing. And I have Xeons with 2Mb of cache. The entire > > accumulated image result can/will live in the L2 cache. If I change cpu's, > > don't I loose the benefit of having the large (and expensive) L2 cache? > > Thats why the kernel will try and keep tasks glued to a CPU. The hard case > is do you idle a CPU for a while or move a task onto it.
Maybe it's an idea to add this change to kernel/sched.c::goodness()
if (p == prev) weight += 1; } --> else if (p->processor != this_cpu) weight = -1; <-- return weight; }
This makes sure that a proces that has run out of time slice doesn't switch CPU just yet (because it's at the head of the run queue or something silly like that).
I think it won't affect the code path or the scheduling behaviour very much, except for the fact that it'll cause processes to stick to their CPU much better.
I'll add it to my patch tonight and see what happens...
Rik -- Open Source: you deserve to be in control of your data. +-------------------------------------------------------------------+ | Le Reseau netwerksystemen BV: http://www.reseau.nl/ | | Linux Memory Management site: http://humbolt.geo.uu.nl/Linux-MM/ | | Nederlandse Linux documentatie: http://www.nl.linux.org/ | +-------------------------------------------------------------------+
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