From: Roland Dreier <redacted>
Date: Tue, 12 Jun 2007 14:52:11 -0700

I think you're misunderstanding.  These NICs still have only one
physical port, so sending or receiving real packets onto a physical
wire is fundamentally serialized.  The steering of packets to receive
queues is done right after the packets are received from the wire --
in fact it can be done as soon as the NIC has parsed enough of the
headers to make a decision, which might be before the full packet has
even been received.  The steering is no more of a bottleneck than the
physical link is.

Yep, that's right.