One of the processor's tasks is to service interrupts and DPCs from all of the computer's subsystems. On a busy server running Internet Information Server, much of the processor's time can be spent servicing interrupts and DPCs, especially from the disk subsystem and the network adapter cards.
This section describes some methods of measuring how much time your server's processors are spending handling interrupts and DPCs from the network adapter cards. It discusses how network card interrupts and DPCs are distributed among processors in multiprocessor computers, and suggests some methods of tuning DPC distribution to improve processor performance.