NAPI changes

NAPI eliminates the incoming packet backlog
Packets are stored on adaptor 
Only read when actually used
Saves system memory and processing
Avoids reordering of packets

Interrupt mitigation
Fast nets can generate thousands of interrupts per second
Interrupts dominate the processor
NAPI runs in polling mode when traffic is heavy
Looks for packets when it can handle them
Busy net = packets always there