commit 16997d15645830a1bd3c5d333826797eba5602eb
Author: evangyzen <eric_van_gyzen@dell.com>
Date:   Fri Aug 22 13:44:00 2014 -0400

    fix sched_ule to honor sched_yield()

diff --git a/sys/kern/sched_ule.c b/sys/kern/sched_ule.c
index cba9d80..97af889 100644
--- a/sys/kern/sched_ule.c
+++ b/sys/kern/sched_ule.c
@@ -1888,7 +1888,8 @@ sched_switch(struct thread *td, struct thread *newtd, int flags)
 	ts->ts_rltick = ticks;
 	td->td_lastcpu = td->td_oncpu;
 	td->td_oncpu = NOCPU;
-	preempted = !(td->td_flags & TDF_SLICEEND);
+	preempted = !((td->td_flags & TDF_SLICEEND) ||
+		(flags & SWT_RELINQUISH));
 	td->td_flags &= ~(TDF_NEEDRESCHED | TDF_SLICEEND);
 	td->td_owepreempt = 0;
 	if (!TD_IS_IDLETHREAD(td))