rx-fpq-bulk-free-20050529

rx-fpq-bulk-free-20050529

FIXES 19027

After profiling RX for a while, I've found a few more bottlenecks in the
packet handling code.  This patch addresses a couple of these issues.
The major change in this patch is a new API to allow bulk packet
alloc/free ops on rx_queue's of packets.  Benefits include reduced lock
contention on rx_freePktQ_lock, elimination of a lot of unnecessary cache
line invalidates, and reduced register window thrashing on sparc.

In addition, this patch dedicates one rx_packet per thread to rxi_SendAck,
since that function is in the critical path, and represents a large
percentage of execution time.