Date: Fri, 11 Mar 2005 17:00:48 +0100
From: Jens Axboe <axboe@suse.de>
To: Simone Piunno <simone.piunno@wseurope.com>
Cc: Fabio Coatti <fabio.coatti@wseurope.com>, Baruch Even <baruch@ev-en.org>,
       Denis Vlasenko <vda@port.imtp.ilyichevsk.odessa.ua>,
       linux-kernel@vger.kernel.org
Subject: Re: bonnie++ uninterruptible under heavy I/O load
Message-ID: <20050311160048.GM28188@suse.de>
References: <200503111208.20283.simone.piunno@wseurope.com> <200503111650.07336.fabio.coatti@wseurope.com> <20050311155400.GL28188@suse.de> <200503111658.04499.simone.piunno@wseurope.com>
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On Fri, Mar 11 2005, Simone Piunno wrote:
> Alle 16:54, venerd? 11 marzo 2005, Jens Axboe ha scritto:
> 
> > I'd guess that your problem is queueing, if you have a ton of pending
> > requests in the hardware it will take forever to get a new request
> > through. There's nothing the io scheduler can do to help you there,
> > really. The /proc/driver/cciss/cciss0 you originall posted, was that
> > from before or after running bonnie++? I have no latency experience with
> > cciss, at least IDE/SATA/SCSI should work alright.
> 
> It was after running bonnie++.

Are you sure? It lists only 190 commands run since it initialized,
that's basically nothing. 6 was the highest depth, should not be enough
to cause serious latency issues unless it was constantly at 6.

-- 
Jens Axboe

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