Thanks.  I will test to see how this affects this lock contention the
next time the broadcom hardware is available.

The other strategy to reduce lock contention here is to use TSO/GSO/USO.
With that the lock has to be taken less often because there are less packets
travelling down the stack. I'm not sure how well that works with netperf style 
workloads though. Using multiple TX queues is probably better though if you have
capable hardware. Or ideally both.

-Andi

-- 
ak@linux.intel.com -- Speaking for myself only.