From: Simon Kirby [off-list ref]
   Date: Thu, 22 May 2003 04:44:38 -0700
   
   There's no APIC on this test box, so it's using the XT-PIC.
   Production has an APIC, so I assume the overhead would be less
   there.

It is absolutely critical for routing throughput.  XT-PIC overhead
severely limits your maximum packets/second switching rate.

Another thing to watch out for are drivers still using PIO to
access device registers (3c59x comes to mind).