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Date: Sun, 17 Aug 2003 19:21:03 -0700
From: Andrew Morton <akpm@osdl.org>
To: Stefan Foerster <stefan@stefan-foerster.de>
Cc: linux-kernel@vger.kernel.org
Subject: Re: Very bad interactivity with 2.6.0 and SCSI disks (aic7xxx)
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Stefan Foerster <stefan@stefan-foerster.de> wrote:
>
> But as soon as I do a
> 
>  while true; do dd if=/dev/zero of=test bs=1024 count=1048576 ; rm test
>  ; done
> 
>  on my SCSI disk, the system becomes completely unusuable after a few
>  seconds.

I've been running an aic7xx-based desktop on 2.5/2.6 for ages, no
such problems.

A kernel profile would be needed to diagnose this.  You could use
readprofile, but as it may be an interrupt problem, the NMI-based oprofile
output would be better.