On Fri, 2012-07-06 at 11:20 +0800, Jason Wang wrote: > On 07/05/2012 08:51 PM, Sasha Levin wrote: > > On Thu, 2012-07-05 at 18:29 +0800, Jason Wang wrote: > >> @@ -1387,6 +1404,10 @@ static int virtnet_probe(struct virtio_device *vdev) > >> if (virtio_has_feature(vdev, VIRTIO_NET_F_CTRL_VQ)) > >> vi->has_cvq = true; > >> > >> + /* Use single tx/rx queue pair as default */ > >> + vi->num_queue_pairs = 1; > >> + vi->total_queue_pairs = num_queue_pairs; > > The code is using this "default" even if the amount of queue pairs it > > wants was specified during initialization. This basically limits any > > device to use 1 pair when starting up. > > > > Yes, currently the virtio-net driver would use 1 txq/txq by default > since multiqueue may not outperform in all kinds of workload. So it's > better to keep it as default and let user enable multiqueue by ethtool -L. I think it makes sense to set it to 1 if the amount of initial queue pairs wasn't specified. On the other hand, if a virtio-net driver was probed to provide VIRTIO_NET_F_MULTIQUEUE and has set something reasonable in virtio_net_config.num_queues, then that setting shouldn't be quietly ignored and reset back to 1. What I'm basically saying is that I agree that the *default* should be 1 - but if the user has explicitly asked for something else during initialization, then the default should be overridden. -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
