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From: Dieter =?iso-8859-15?q?N=FCtzel?= <Dieter.Nuetzel@hamburg.de>
Organization: DN
To: Bill Davidsen <davidsen@tmr.com>
Subject: Re: [2.4.17/18pre] VM and swap - it's really unusable
Date: Mon, 14 Jan 2002 03:12:57 +0100
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        Andrew Morton <akpm@zip.com.au>
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> Or just doing a large write while doing lots of reads... my personal
> nemesis is "mkisofs" for backups, which reads lots of small files and
> builds a CD image, which suddenly gets discovered by the kernel and
> written, seemingly in a monolythic chunk. I MAY be able to improve this
> with tuning the bdflush parameters, and I tried some tentative patches
> which didn't make a huge gain.
>
> I don't know if the solution lies in forcing write to start when a certain
> size of buffers are queued regardless of percentages, or in better
> scheduling of reads ahead of writes, or whatever.

Have you observed it with -rmap or -aa, too?
I bet, you have.

Try Andrew's read-latency.patch then.
I use it on top of O(1) and preempt all the time.
It should be one of the next 2.4.18-preX/2.4.19-preX patches.

Regards,
	Dieter

-- 
Dieter N?tzel
Graduate Student, Computer Science

University of Hamburg
Department of Computer Science
@home: Dieter.Nuetzel@hamburg.de
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