On 06/11/2012 06:34 PM, Whit Blauvelt wrote:
Looking into background info on these, it looks like SR-IOV capability is specific to certain NICs and not documented for KVM/libvirt in any obvious place. Maybe I just didn't find it.
I think SR-IOV is more for high-end 10 GigE networks; with 1 GigE NICs and fairly modern hardware you should get decent performance (almost wire-speed) with just simple virtio + bridge setup. Also, make sure you have the vhost_net module loaded (or kernel compiled with CONFIG_VHOST_NET=y), recent (0.9.0 and newer I believe?) libvirt versions should detect it and enable vhost=on with QEMU/KVM automatically. That should give you some further performance boost. I agree that there is some room for improvement in libvirt documentation regarding the network configuration.