diff -ruNp --exclude compile sys.prev2/powerpc/aim/machdep.c sys/powerpc/aim/machdep.c
--- sys.prev2/powerpc/aim/machdep.c	2010-09-03 02:15:35.000000000 +0300
+++ sys/powerpc/aim/machdep.c	2010-09-05 10:34:45.000000000 +0300
@@ -639,7 +638,13 @@ cpu_idle(int busy)
 		panic("ints disabled in idleproc!");
 	}
 #endif
+	CTR2(KTR_SPARE2, "cpu_idle(%d) at %d",
+	    busy, curcpu);
 	if (powerpc_pow_enabled) {
+		if (!busy) {
+			critical_enter();
+			cpu_idleclock();
+		}
 		switch (vers) {
 		case IBM970:
 		case IBM970FX:
@@ -659,7 +664,13 @@ cpu_idle(int busy)
 			isync();
 			break;
 		}
+		if (!busy) {
+			cpu_activeclock();
+			critical_exit();
+		}
 	}
+	CTR2(KTR_SPARE2, "cpu_idle(%d) at %d done",
+	    busy, curcpu);
 }
 
 int
diff -ruNp --exclude compile sys.prev2/powerpc/booke/machdep.c sys/powerpc/booke/machdep.c
--- sys.prev2/powerpc/booke/machdep.c	2010-09-03 02:15:34.000000000 +0300
+++ sys/powerpc/booke/machdep.c	2010-09-05 18:04:07.000000000 +0300
@@ -488,9 +488,21 @@ cpu_idle (int busy)
 	}
 #endif
 
+	CTR2(KTR_SPARE2, "cpu_idle(%d) at %d",
+	    busy, curcpu);
+	if (!busy) {
+		critical_enter();
+		cpu_idleclock();
+	}
 	/* Freescale E500 core RM section 6.4.1. */
 	msr = msr | PSL_WE;
 	__asm __volatile("msync; mtmsr %0; isync" :: "r" (msr));
+	if (!busy) {
+		cpu_activeclock();
+		critical_exit();
+	}
+	CTR2(KTR_SPARE2, "cpu_idle(%d) at %d done",
+	    busy, curcpu);
 }
 
 int