[libvirt-users] How can a bridge be optimized?

[Henrik Ahlgren]

On Fri, Jun 01, 2012 at 05:15:35PM -0400, Whit Blauvelt wrote:
> Netperf tells me that a KVM VM using a bridged connection to a system across
> the Gigabit LAN sees on average about 1/10th of the bandwidth the host sees.

What NIC are you using? For example with the Intel 10 GigE cards
(ixgbe) it is essential to turn off LRO using ethtool when using
bridges, otherwise the performance sucks.

And, surely you're using the paravirtualized virtio interface in your
guest?

> I recall the kernel recently adding a new alternative for handling VM
> interfaces, but can't recall what it was called. Would that be a marked
> improvement? Is it supported by libvirt?

Look for SR-IOV.