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Date: Tue, 1 Oct 2002 14:29:26 -0300 (BRT)
From: Rik van Riel <riel@conectiva.com.br>
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To: Daniel Phillips <phillips@arcor.de>
Cc: Andrew Morton <akpm@digeo.com>,
       Lorenzo Allegrucci <l.allegrucci@tiscalinet.it>,
       Linux Kernel <linux-kernel@vger.kernel.org>
Subject: Re: qsbench, interesting results
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On Tue, 1 Oct 2002, Daniel Phillips wrote:
> On Tuesday 01 October 2002 19:13, Rik van Riel wrote:
> > With one process that needs 150% of RAM as its working set,
> > there simply is no way to win.
>
> True, the object is merely to suck as little as possible.  Note that
> 2.4.xx trounces 2.5.xx rather soundly on the test in question.

Every page replacement system has a worst case, 2.5 is closer to
LRU than 2.4 and it's well possible that the randomisation 2.4
does means we don't trigger the worst case here.

I don't know for sure, but I have a feeling that EVERY algorithm
for page replacement can be tricked into performing worse than
random page replacement for some particular workload.  It might
even be provable ;)

> > > Try loading a high res photo in gimp and running any kind of interesting
> > > script-fu on it.  If it doesn't thrash, boot with half the memory and
> > > repeat.
> >
> > But, should just the gimp thrash, or should every process on the
> > machine thrash ?
>
> Gimp should thrash exactly as much as it needs to, to get its job
> done.  No competition, remember?

No competition ?  I know _I_ don't have a machine dedicated to
gimp and I like to be able to continue listening to mp3s while
the gimp is chewing on a large image...

cheers,

Rik
-- 
A: No.
Q: Should I include quotations after my reply?

http://www.surriel.com/		http://distro.conectiva.com/

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