Re: [PATCH] virtio: Use ioeventfd for virtqueue notify

Avi Kivity
2010-10-03T14:22:06Z

On 10/03/2010 03:51 PM, Michael S. Tsirkin wrote:
> On Sun, Oct 03, 2010 at 01:01:59PM +0200, Avi Kivity wrote:
> > >
> > >Guest to Host TCP_STREAM throughput(Mb/sec)
> > >-------------------------------------------
> > >Msg Size vhost-net virtio-net virtio-net/ioeventfd
> > >65536 12755 6430 7590
> > >16384 8499 3084 5764
> > > 4096 4723 1578 3659
> > > 1024 1827 981 2060
> >
> > Even more impressive (expected since the copying, which isn't
> > present for block, is now shunted off into an iothread).
> >
> > On the last test you even exceeded vhost-net. Any theories how/why?
> >
> > Again, efficiency numbers would be interesting.
> >
> > >Host to Guest TCP_STREAM throughput(Mb/sec)
> > >-------------------------------------------
> > >Msg Size vhost-net virtio-net virtio-net/ioeventfd
> > >65536 11156 5790 5853
> > >16384 10787 5575 5691
> > > 4096 10452 5556 4277
> > > 1024 4437 3671 5277
> >
> > Here you exceed vhost-net, too.
>
> This is with small packets- I suspect this is the extra
> per interrupt overhead that eventfd has.

This is using eventfd as well.

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