On Thu, Apr 22, 2010 at 04:57:56PM +0800, Xin, Xiaohui wrote: > Michael, > > >Yes, I think this packet split mode probably maps well to mergeable buffer > >support. Note that > >1. Not all devices support large packets in this way, others might map > > to indirect buffers better > > Do the indirect buffers accord to deal with the skb->frag_list? We currently use skb->frags. > > So we have to figure out how migration is going to work > Yes, different guest virtio-net driver may contain different features. > Does the qemu migration work with different features supported by virtio-net > driver now? For now, you must have identical feature-sets for migration to work. And long as we manage the buffers in software, we can always make features match. > >2. It's up to guest driver whether to enable features such as > > mergeable buffers and indirect buffers > > So we have to figure out how to notify guest which mode > > is optimal for a given device > Yes. When a device is binded, the mp device may query the capabilities from driver. > Actually, there is a structure now in mp device can do this, we can add some field > to support more. > > >3. We don't want to depend on jumbo frames for decent performance > > So we probably should support GSO/GRO > GSO is for the tx side, right? I think driver can handle it itself. > For GRO, I'm not sure it's easy or not. Basically, the mp device now > we have support is doing what raw socket is doing. The packets are not going to host stack. See commit bfd5f4a3d605e0f6054df0b59fe0907ff7e696d3 (it doesn't currently work with vhost net, but that's a separate story). > -- > MST -- 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
