Re: [PATCH 09/21] Introduce event-tap.

Stefan Hajnoczi
2011-01-04T11:14:55Z

On Tue, Jan 4, 2011 at 11:02 AM, Yoshiaki Tamura
<tamura.yoshiaki@lab.ntt.co.jp> wrote:
> After doing some heavy load tests, I realized that we have to
> take a hybrid approach to replay for now.  This is because when a
> device moves to the next state (e.g. virtio decreases inuse) is
> different between net and block.  For example, virtio-net
> decreases inuse upon returning from the net layer, but virtio-blk
> does that inside of the callback.  If we only use pio/mmio
> replay, even though event-tap tries to replay net requests, some
> get lost because the state has proceeded already.  This doesn't
> happen with block, because the state is still old enough to
> replay.  Note that using hybrid approach won't cause duplicated
> requests on the secondary.

Thanks Yoshi. I think I understand what you're saying.

Stefan