Re: 2.6.0-test9 - poor swap performance on low end machines

From: Roger Luethi
Date: Fri Oct 31 2003 - 08:05:12 EST


On Fri, 31 Oct 2003 23:37:34 +1100, Con Kolivas wrote:
> Yes it will show improvement, and I would like to hear how much given how

I've been sitting on my data because I was waiting for the missing
pieces from my test box, but here's a data point: For my test case,
your patch improves run time from 500 to 440 seconds.

> simple it is, but I agree with you. There is an intrinsic difference in the
> vm in 2.6 that makes it too hard for multiple running applications to have a

My (probably surprising to many) finding is that there _isn't_
an intrinsic difference which makes 2.6 suck. There are a number of
_separate_ issues, and they are only related in their contribution to
making 2.6 thrashing behavior abysmal.

What I'm trying to find out is whether the issues are intrinsic to
a change in some mechanisms (which typically means it's a price we
have to pay for other benefits) or if they are just problems with the
implementation. I had tracked down vm_swappiness as one problem, and
your solution shows that the implementation could indeed be improved
without touching the fundamental VM workings at all.

Roger
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