diff --git a/lib/libpmc/libpmc.c b/lib/libpmc/libpmc.c
index 75a33a9f6aa7..658e6b7b717e 100644
--- a/lib/libpmc/libpmc.c
+++ b/lib/libpmc/libpmc.c
@@ -1,5 +1,5 @@
 /*-
- * Copyright (c) 2003-2005 Joseph Koshy
+ * Copyright (c) 2003-2006 Joseph Koshy
  * All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
@@ -319,6 +319,7 @@ static struct pmc_event_alias k8_aliases[] = {
 	EV_ALIAS("ic-misses",		"k8-ic-miss"),
 	EV_ALIAS("instructions", 	"k8-fr-retired-x86-instructions"),
 	EV_ALIAS("interrupts",		"k8-fr-taken-hardware-interrupts"),
+	EV_ALIAS("unhalted-cycles",	"k8-bu-cpu-clk-unhalted"),
 	EV_ALIAS(NULL, NULL)
 };
 
@@ -682,6 +683,7 @@ static struct pmc_event_alias p4_aliases[] = {
 	EV_ALIAS("cycles",		"tsc"),
 	EV_ALIAS("instructions",
 	    "p4-instr-retired,mask=nbogusntag+nbogustag"),
+	EV_ALIAS("unhalted-cycles",	"p4-global-power-events"),
 	EV_ALIAS(NULL, NULL)
 };
 
@@ -1316,6 +1318,7 @@ static struct pmc_event_alias p6_aliases[] = {
 	EV_ALIAS("ic-misses",		"p6-ifu-ifetch-miss"),
 	EV_ALIAS("instructions",	"p6-inst-retired"),
 	EV_ALIAS("interrupts",		"p6-hw-int-rx"),
+	EV_ALIAS("unhalted-cycles",	"p6-cpu-clk-unhalted"),
 	EV_ALIAS(NULL, NULL)
 };
 
diff --git a/lib/libpmc/pmc.3 b/lib/libpmc/pmc.3
index a3925d89c54f..f9da5af04967 100644
--- a/lib/libpmc/pmc.3
+++ b/lib/libpmc/pmc.3
@@ -1,4 +1,4 @@
-.\" Copyright (c) 2003-2005 Joseph Koshy.  All rights reserved.
+.\" Copyright (c) 2003-2006 Joseph Koshy.  All rights reserved.
 .\"
 .\" Redistribution and use in source and binary forms, with or without
 .\" modification, are permitted provided that the following conditions
@@ -23,7 +23,7 @@
 .\"
 .\" $FreeBSD$
 .\"
-.Dd June 24, 2005
+.Dd March 19, 2006
 .Os
 .Dt PMC 3
 .Sh NAME
@@ -454,6 +454,9 @@ Measure the number of instruction cache misses.
 Measure the number of instructions retired.
 .It Li interrupts
 Measure the number of interrupts seen.
+.It Li unhalted-cycles
+Measure the number of cycles the processor is not in a halted
+or sleep state.
 .El
 .Ss Time Stamp Counter (TSC)
 The timestamp counter is a monotonically non-decreasing counter that