diff --git a/sys/kern/kern_time.c b/sys/kern/kern_time.c
--- a/sys/kern/kern_time.c
+++ b/sys/kern/kern_time.c
@@ -504,24 +504,27 @@
 	sbintime_t sbt, sbtt, prec, tmp;
 	time_t over;
 	int error;
-	bool is_abs_real;
+	bool is_abs_real, precise;
 
 	if (rqt->tv_nsec < 0 || rqt->tv_nsec >= NS_PER_SEC)
 		return (EINVAL);
 	if ((flags & ~TIMER_ABSTIME) != 0)
 		return (EINVAL);
+	precise = false;
 	switch (clock_id) {
 	case CLOCK_REALTIME:
 	case CLOCK_REALTIME_PRECISE:
+		precise = true;
 	case CLOCK_REALTIME_FAST:
 	case CLOCK_SECOND:
 		is_abs_real = (flags & TIMER_ABSTIME) != 0;
 		break;
 	case CLOCK_MONOTONIC:
-	case CLOCK_MONOTONIC_PRECISE:
-	case CLOCK_MONOTONIC_FAST:
 	case CLOCK_UPTIME:
+	case CLOCK_MONOTONIC_PRECISE:
 	case CLOCK_UPTIME_PRECISE:
+		precise = true;
+	case CLOCK_MONOTONIC_FAST:
 	case CLOCK_UPTIME_FAST:
 		is_abs_real = false;
 		break;
@@ -553,10 +556,13 @@
 		} else
 			over = 0;
 		tmp = tstosbt(ts);
-		prec = tmp;
-		prec >>= tc_precexp;
-		if (TIMESEL(&sbt, tmp))
-			sbt += tc_tick_sbt;
+		if (precise) {
+			prec = 0;
+		} else {
+			prec = tmp >> tc_precexp;
+			if (TIMESEL(&sbt, tmp))
+				sbt += tc_tick_sbt;
+		}
 		sbt += tmp;
 		error = tsleep_sbt(&nanowait[curcpu], PWAIT | PCATCH, "nanslp",
 		    sbt, prec, C_ABSOLUTE);