Index: sys/kern/kern_synch.c
===================================================================
--- sys/kern/kern_synch.c
+++ sys/kern/kern_synch.c
@@ -437,6 +437,11 @@
 	CTR4(KTR_PROC, "mi_switch: new thread %ld (td_sched %p, pid %ld, %s)",
 	    td->td_tid, td_get_sched(td), td->td_proc->p_pid, td->td_name);
 
+	if (flags & SW_VOL)
+		td->td_swvoltick = ticks;
+	else
+		td->td_swinvoltick = ticks;
+
 	/* 
 	 * If the last thread was exiting, finish cleaning it up.
 	 */