Re: 2.6.15-rc5-mm3

From: Con Kolivas
Date: Wed Dec 21 2005 - 23:20:20 EST


Jesper Juhl writes:

On 12/15/05, Andrew Morton <akpm@xxxxxxxx> wrote:

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-mm-implement-swap-prefetching.patch
-mm-implement-swap-prefetching-default-y.patch
-mm-implement-swap-prefetching-tweaks.patch
-mm-implement-swap-prefetching-tweaks-2.patch
-mm-swap-prefetch-magnify.patch

Dropped swap prefetching, sorry. I wasn't able to notice much benefit from
it in my testing, and the number of mm/ patches in getting crazy, so we don't
have capacity for speculative things at present.

<!-- snip -->

This is a bit sad.
On my system (1.4GHz Athlon w/512MB RAM, 768MB swap) this did have an effect.
One situation in particular where it helped (and which is a common
case for me) was when I had OpenOffice2 + Eclipse (with CDT) + xchat +
nedit + Firefox + a few konsole windows open (running KDE 3.5 btw and
all apps usually have a lot of content loaded), minimized all the apps
and then started an allyesconfig build in one window - the
allyesconfig build would drag the machine to its knees and eat up more
or less all RAM + swap, so I usually left it alone for a while to
finish and when I then came back later and reactivated the apps I had
minimized they came back pretty fast. Without the swap prefetch
patches things come back somewhat slower - it's not an earth
shattering difference, but it's definately noticable.

Apart from the feedback I've gotten directly from users of the -ck patchset incorporating this, Andrew and lkml has had very few reports about it until he decided to drop it. I'm still maintaining the code in -ck indefinitely for the moment. Here's hoping he picks it up again in the future.

Cheers,
Con

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