--- README	Fri Apr 27 23:32:56 2001
+++ README	Fri Apr 27 22:57:38 2001
@@ -18,7 +18,8 @@ 
 	-i	invert sense of count mask comparison
 	-U n	use unit mask `n'
 
-There is one mandatory argument, which must be the number of the counter.
+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).
 
 $FreeBSD: src/share/examples/perfmon/README,v 1.4 1999/08/28 00:19:26 peter Exp $