`perfmon' is a sample program to access the performance-monitoring
counters on Pentium and Pentium Pro CPUs.  See perfmon(4) for a
description of this facility.

The program takes the following options:

	-u	count events in user mode
	-o	count events in kernel mode
		(these two can be combined)

	-e	count events, not duration
	-l n	run `n' loops (default 50)
	-s n	sleep `n' seconds between loop iterations (default 0)

The following options are not implemented on Pentium CPUs:

	-m n	use count mask `n'
	-i	invert sense of count mask comparison
	-U n	use unit mask `n'

There is one mandatory argument, which is the event number to be
monitored, defined in <machine/perfmon.h>.  All numbers can be
specified in any format acceptable to strtol(3).