diff --git a/sys/sys/time.h b/sys/sys/time.h
index 1039c2216de..fbef8b77482 100644
--- a/sys/sys/time.h
+++ b/sys/sys/time.h
@@ -90,6 +90,25 @@ bintime_sub(struct bintime *bt, const struct bintime *bt2)
 	bt->sec -= bt2->sec;
 }
 
+static __inline void
+bintime_mul(struct bintime *bt, u_int x)
+{
+	uint64_t p1, p2;
+
+	p1 = (bt->frac & 0xffffffffllu) * x;
+	p2 = (bt->frac >> 32) * x + (p1 >> 32);
+	bt->sec *= x;
+	bt->sec += (p2 >> 32);
+	bt->frac = (p2 << 32) | (p1 & 0xffffffffllu);
+}
+
+#define	bintime_clear(a)	((a)->sec = (a)->frac = 0)
+#define	bintime_isset(a)	((a)->sec || (a)->frac)
+#define	bintime_cmp(a, b, cmp)						\
+	(((a)->sec == (b)->sec) ?					\
+	    ((a)->frac cmp (b)->frac) :					\
+	    ((a)->sec cmp (b)->sec))
+
 /*-
  * Background information:
  *