diff --git a/sys/kern/kern_synch.c b/sys/kern/kern_synch.c
--- a/sys/kern/kern_synch.c
+++ b/sys/kern/kern_synch.c
@@ -658,7 +658,7 @@
 	loadav(NULL);
 }
 
-int
+bool
 should_yield(void)
 {
 
diff --git a/sys/sys/proc.h b/sys/sys/proc.h
--- a/sys/sys/proc.h
+++ b/sys/sys/proc.h
@@ -1217,7 +1217,7 @@
 void	sess_release(struct session *);
 int	setrunnable(struct thread *, int);
 void	setsugid(struct proc *p);
-int	should_yield(void);
+bool	should_yield(void);
 int	sigonstack(size_t sp);
 void	stopevent(struct proc *, u_int, u_int);
 struct	thread *tdfind(lwpid_t, pid_t);