On Tue, 2011-02-01 at 22:05 -0800, Shirley Ma wrote:

The way I am changing is only when netif queue has stopped, then we
start to count num_free descriptors to send the signal to wake netif
queue. 

I forgot to mention, the code change I am making is in guest kernel, in
xmit call back only wake up the queue when it's stopped && num_free >=
1/2 *vq->num, I add a new API in virtio_ring.

However vhost signaling reduction is needed as well. The patch I
submitted a while ago showed both CPUs and BW improvement.

Thanks
Shirley