Subject: Re: TCP stalls with 802.3ad + bridge + kvm guest

From: Stephen Hemminger <[email-masked]>
Date: Sat, 11 Aug 2012 11:28:40 -0700

On Sat, 4 Aug 2012 17:45:11 -0500
Peter Samuelson <[email-masked]> wrote:

> 
> > [Jesse Brandeburg]
> > > try
> > > # ethtool -K ethx tso off gso off lro off
> 
> Specifically, 'lro off' is the trick.  The others don't have a
> noticeable effect.  Now I can get 70 MB/s or better most of the time,
> in either direction.
> 
> Thanks again,
> Peter

When device is added to bridge, the bridge code does ask the device
to turn LRO off (automatically). Unfortunately some device drivers are
broken.