Messages in this thread | | | From | Con Kolivas <> | Subject | Re: [PATCH] mm: yield during swap prefetching | Date | Wed, 8 Mar 2006 12:28:05 +1100 |
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On Wed, 8 Mar 2006 12:23 pm, Andrew Morton wrote: > Con Kolivas <kernel@kolivas.org> wrote: > > > but, but. If prefetching is prefetching stuff which that game will > > > soon use then it'll be an aggregate improvement. If prefetch is > > > prefetching stuff which that game _won't_ use then prefetch is busted. > > > Using yield() to artificially cripple kprefetchd is a rather sad > > > workaround isn't it? > > > > It's not the stuff that it prefetches that's the problem; it's the disk > > access. > > But the prefetch code tries to avoid prefetching when the disk is otherwise > busy (or it should - we discussed that a bit a while ago).
Anything that does disk access delays prefetch fine. Things that only do heavy cpu do not delay prefetch. Anything reading from disk will be noticeable during 3d gaming.
> Sorry, I'm not trying to be awkward here - I think that nobbling prefetch > when there's a lot of CPU activity is just the wrong thing to do and it'll > harm other workloads.
I can't distinguish between when cpu activity is important (game) and when it is not (compile), and assuming worst case scenario and not doing any swap prefetching is my intent. I could add cpu accounting to prefetch_suitable() instead, but that gets rather messy and yielding achieves the same endpoint.
Cheers, Con - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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