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

To: Ian Pratt <m+Ian.Pratt@xxxxxxxxxxxx>
Subject: Re: [Xen-devel] poor domU VBD performance.
From: Jens Axboe <axboe@xxxxxxx>
Date: Thu, 31 Mar 2005 20:04:02 +0200
Cc: Xen development list <xen-devel@xxxxxxxxxxxxxxxxxxx>, Kurt Garloff <garloff@xxxxxxx>, Philip R Auld <pauld@xxxxxxxxxxx>, Vincent Hanquez <tab@xxxxxxxxx>, Christian Limpach <Christian.Limpach@xxxxxxxxxxxx>
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On Thu, Mar 31 2005, Ian Pratt wrote:
> > > 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,
> Thanks for your help on this.
> Here's Keirs updated patch:
> http://xen.bkbits.net:8080/xen-2.0-testing.bk/gnupatch@424c1abd7LgWMiask
> Which is based on this earlier patch from you:
> http://xen.bkbits.net:8080/xen-2.0-testing.bk/gnupatch@424bba4091aV1FuNk
> sY_4w_z4Tvr3g

I cannot immediately see if you call bdev_put() right after queueing the
io? If so, I think the patch looks fine. If not, you are missing the
last unplug :-)

Jens Axboe

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