cvs commit: src/sys/net if.h

[Kip Macy]

> I think its a windowism, stands for Receive Side Scaling, and what it means
> is multiple receive queues, each with an MSI/X vector so they can interrupt
> different CPUs, or they can be tied to virtual guests, or MACs, etc etc...

AFAICT FreeBSD can't currently benefit from this as there is no cpu
affinity for connections. I may be wrong, but I see lower
single-connection throughput using a receive queue per core than using
a single receive queue. RSS is done by hashing a TCP tuple (I'm
deliberately vague because at least with cxgb there are multiple
combinations, the default is the standard 4-tuple) to a receive queue.

 -Kip