From mboxrd@z Thu Jan  1 00:00:00 1970
From: Stephen Hemminger <shemminger@vyatta.com>
Subject: Re: TCP stalls with 802.3ad + bridge + kvm guest
Date: Sat, 11 Aug 2012 11:28:40 -0700
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Cc: Jesse Brandeburg <jesse.brandeburg@gmail.com>,
	Jay Vosburgh <fubar@us.ibm.com>, netdev@vger.kernel.org,
	jgoerzen@efolder.net
To: Peter Samuelson <psamuelson@efolder.net>
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On Sat, 4 Aug 2012 17:45:11 -0500
Peter Samuelson <psamuelson@efolder.net> 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.