Message-ID: <3CACD3BC.1EB55BCC@zip.com.au>
Date: Thu, 04 Apr 2002 14:29:16 -0800
From: Andrew Morton <akpm@zip.com.au>
MIME-Version: 1.0
To: Ricardo Galli <gallir@uib.es>
CC: linux-kernel@vger.kernel.org
Subject: Re: Report: 2.4.18 very high latencies (with lowlat. and pre-empt 
 patches)
In-Reply-To: <E16tEL4-0006fr-00@antoli.gallimedina.net>
Content-Type: text/plain; charset=us-ascii
Content-Transfer-Encoding: 7bit
Sender: linux-kernel-owner@vger.kernel.org

Ricardo Galli wrote:
> 
> Hi all (second try),
>         Linux becomes somehow unusable when I edited sound files and also
> during NFS copy. I've noticed the same effects also during i/o loads, for
> example when closing kmail after I deleted some messages.
> 

It would help if you could come up with a simple test case
which exhibits this problem - some sequence of steps which
is reproducible by others, and which has repeatable effects.

Is your I/O system performing properly?  Try running

	hdparm -t /dev/hdaX

where /dev/hdaX refers to your root filesystem.  You
should get 15-30 megabytes per second.

You also report that your PPC-based laptop has processes
unexpectedly terminating when the machine is under VM
pressure.  You should check your kernel logs (usually
/var/log/messages) to see if the process was killed
due to an out-of-memory condition.  If it's not that,
and if it's not due to application bugs then the ppc
kernel may be dropping modified- or dirty-bits in its
PTEs, which is rather unlikely.

-
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/