Time spent handling interrupts, context switches

[Dan Ellard]

Has anyone ever done any testing to measure the percentage
of time the UNIX kernel spends handling interrupts (i.e. in the interrupt
context), or in context switching for moderately loaded systems? 

I'm mostly interested in data about BSD-flavored UNIX or MACH, but
info about any other flavor of UNIX or other operating systems like
VAX/VMS, OS/360, MULTICS, etc. would be useful too.

Thanks,
	Dan