10gbps pf nat firewall ix to mcx

[Chris Cappuccio]

huh, after i migrated nat fw from 82599 (ix) with LRO on (default) to 
a CX4121A (mcx) flashed to latest nvidia firmware and now i'm getting
900mbps on single tcp throughput (endpoints still using lro on
em and ix) and very consistently getting close to the full 1gbps
thruoghput on single tcp connections now instead of slower and slightly
varying results. guess i should go back and test ix with LRO off on
the pf box.