Re: Which is better at vm, and why? 2.2 or 2.4

From: Patrick McFarland (unknown@panax.com)
Date: Sat Oct 13 2001 - 13:42:20 EST


Ill reiterate something here, im on a p133 with 16 megs. Yeah, the kind of the crappy ide controller that eats cpu time to swap. (Enough so that my mouse pointer will freeze in X that its swapping so much. Swapping is the only thing ive found that can pull that off) Swapping the least ammount would be the best for a box like that.

On 13-Oct-2001, Rik van Riel wrote:
> On Sat, 13 Oct 2001, Patrick McFarland wrote:
>
> > Hmm, I see that as very bad. There should be a bunch of sysctls to do
> > that easily.
>
> See /proc/sys/vm/* and the documentation ;)
>
> > Also, I heard that 2.4 (and I'm assuming 2.2 as well) swaps pages on a
> > last-used-age basis, instead of either a number-of-times-used or a
> > hybrid of the two. That kinda seems stupid,
>
> Don't worry since it's not true, at least the VM in the -ac
> kernels _does_ use a hybrid of access recency and frequency
> to determine page replacement.
>
> The -linus kernel, however only has LRU-like selection.
>
> At the moment the -linus kernel is faster than the -ac kernel
> for some workloads. This may have something to do with better
> clusterable IO ... when page replacement is less precise the
> chance that IO is clusterable is probably larger due to the
> way we scan.
>
> I plan to do more explicit IO clustering in -ac to try and
> remedy this difference.
>
> regards,
>
> Rik
> --
> DMCA, SSSCA, W3C? Who cares? http://thefreeworld.net/ (volunteers needed)
>
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>

-- 
Patrick "Diablo-D3" McFarland || unknown@panax.com


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