Re: bonnie++ uninterruptible under heavy I/O load

From: Jens Axboe
Date: Fri Mar 11 2005 - 11:11:48 EST


On Fri, Mar 11 2005, Simone Piunno wrote:
> Alle 16:54, venerdì 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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