Re: [Xen-devel] poor domU VBD performance.

[Jens Axboe <axboe@xxxxxxx>]

On Thu, Mar 31 2005, Keir Fraser wrote:
> 
> On 31 Mar 2005, at 16:39, Jens Axboe wrote:
> 
> >Not necessarily - either your io rate is not fast enough to sustain a
> >substantial queue depth, in that case you get plugging on basically
> >every io anyways. If on the other hand the io rate is high enough to
> >maintain a queue depth of > 1, then the plugging will never take place
> >because the queue never empties.
> >
> >So all in all, I don't think the temporary work-around will be such a
> >bad idea. I would still rather implement the queue tracking though, it
> >should not be more than a few lines of code.
> 
> I've checked in something along the lines of what you described into 
> both the 2.0-testing and the unstable trees. Looks to have identical 
> performance to the original simple patch, at least for a bulk 'dd'.

Can you post the patch here for review? Or just point me somewhere I can
view it.

-- 
Jens Axboe


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