Index: sched_ule.c
===================================================================
RCS file: /home/ncvs/src/sys/kern/sched_ule.c,v
retrieving revision 1.214.2.2
diff -u -r1.214.2.2 sched_ule.c
--- sched_ule.c	20 Dec 2007 07:15:40 -0000	1.214.2.2
+++ sched_ule.c	2 Jan 2008 13:31:10 -0000
@@ -2183,17 +2183,16 @@
 			tdq->tdq_ridx = tdq->tdq_idx;
 	}
 	ts = td->td_sched;
-	/*
-	 * We only do slicing code for TIMESHARE threads.
-	 */
-	if (td->td_pri_class != PRI_TIMESHARE)
+	if (td->td_pri_class & PRI_FIFO_BIT)
 		return;
-	/*
-	 * We used a tick; charge it to the thread so that we can compute our
-	 * interactivity.
-	 */
-	td->td_sched->ts_runtime += tickincr;
-	sched_interact_update(td);
+	if (td->td_pri_class == PRI_TIMESHARE) {
+		/*
+		 * We used a tick; charge it to the thread so
+		 * that we can compute our interactivity.
+		 */
+		td->td_sched->ts_runtime += tickincr;
+		sched_interact_update(td);
+	}
 	/*
 	 * We used up one time slice.
 	 */