Re: [PATCH 1/1] cciss per disk queue for 2.6

Jens Axboe
2005-07-01T18:19:57Z

On Fri, Jul 01 2005, Miller, Mike (OS Dev) wrote:
> Jens Axboe wrote:
> > Different thing, I'm talking about single volume starvation,
> > not volume-to-volume.
> >
> > > elevator algoritm(s) may be causing writes to starve reads
> > on the same
> > > logical volume. We continue to investigate our other
> > performance issues.
> >
> > I completely disagree. Even with an intelligent io scheduler,
> > starvation is seen on ciss that does not happen on other
> > queueing hardware such as 'normal' scsi controllers/drives.
> > So something else is going on, and the only 'fix' so far is
> > to limit the ciss queue depth heavily.
>
> We will investigate this further and come up with a solution. Could be
> the firmware, I suppose.

Unfortunately I don't have any hardware at hand for testing, so I cannot
do it myself. Would be appreciated!

--
Jens Axboe