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Date: Fri, 2 Nov 2012 16:48:12 +0200
From: "Michael S. Tsirkin" <mst@redhat.com>
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Subject: Re: [Qemu-devel] [PATCH] virtio: limit avail bytes lookahead
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To: Stefan Hajnoczi <stefanha@gmail.com>
Cc: Amit Shah <amit.shah@redhat.com>, Edivaldo de Araujo Pereira <edivaldoapereira@yahoo.com.br>, qemu-devel <qemu-devel@nongnu.org>, Anthony Liguori <anthony@codemonkey.ws>, Bug 1066055 <1066055@bugs.launchpad.net>

On Fri, Nov 02, 2012 at 11:18:18AM +0100, Stefan Hajnoczi wrote:
> On Thu, Nov 1, 2012 at 5:07 PM, Michael S. Tsirkin <mst@redhat.com> wrote:
> > Commit 0d8d7690850eb0cf2b2b60933cf47669a6b6f18f introduced
> > a regression in virtio-net performance because it looks
> > into the ring aggressively while we really only care
> > about a single packet worth of buffers.
> > To fix, add parameters limiting lookahead, and
> > use in virtqueue_avail_bytes.
> >
> > Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
> > Reported-by: Edivaldo de Araujo Pereira <edivaldoapereira@yahoo.com.br>
> 
> Nice, much simpler than the ideas I had.
> 
> Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>

Anthony could you apply this out of band please so this stops
biting people?

Thanks,
MST