diff --git a/src/usr.sbin/ntpd/constraint.c b/src/usr.sbin/ntpd/constraint.c
index 166e037f..13c05f92 100644
--- a/src/usr.sbin/ntpd/constraint.c
+++ b/src/usr.sbin/ntpd/constraint.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: constraint.c,v 1.43 2019/05/28 06:49:46 otto Exp $	*/
+/*	$OpenBSD: constraint.c,v 1.44 2019/05/30 13:42:19 otto Exp $	*/
 
 /*
  * Copyright (c) 2015 Reyk Floeter <reyk@openbsd.org>
@@ -41,6 +41,7 @@
 #include <ctype.h>
 #include <tls.h>
 #include <pwd.h>
+#include <math.h>
 
 #include "ntpd.h"
 
@@ -773,7 +774,7 @@ constraint_update(void)
 {
 	struct constraint *cstr;
 	int	 cnt, i;
-	time_t	*sum;
+	time_t	*values;
 	time_t	 now;
 
 	now = getmonotime();
@@ -784,29 +785,31 @@ constraint_update(void)
 			continue;
 		cnt++;
 	}
+	if (cnt == 0)
+		return;
 
-	if ((sum = calloc(cnt, sizeof(time_t))) == NULL)
+	if ((values = calloc(cnt, sizeof(time_t))) == NULL)
 		fatal("calloc");
 
 	i = 0;
 	TAILQ_FOREACH(cstr, &conf->constraints, entry) {
 		if (cstr->state != STATE_REPLY_RECEIVED)
 			continue;
-		sum[i++] = cstr->constraint + (now - cstr->last);
+		values[i++] = cstr->constraint + (now - cstr->last);
 	}
 
-	qsort(sum, cnt, sizeof(time_t), constraint_cmp);
+	qsort(values, cnt, sizeof(time_t), constraint_cmp);
 
 	/* calculate median */
 	i = cnt / 2;
 	if (cnt % 2 == 0)
-		if (sum[i - 1] < sum[i])
-			i -= 1;
+		conf->constraint_median = (values[i - 1] + values[i]) / 2;
+	else
+		conf->constraint_median = values[i];
 
 	conf->constraint_last = now;
-	conf->constraint_median = sum[i];
 
-	free(sum);
+	free(values);
 }
 
 void
@@ -826,7 +829,7 @@ int
 constraint_check(double val)
 {
 	struct timeval	tv;
-	double		constraint;
+	double		diff;
 	time_t		now;
 
 	if (conf->constraint_median == 0)
@@ -836,10 +839,9 @@ constraint_check(double val)
 	now = getmonotime();
 	tv.tv_sec = conf->constraint_median + (now - conf->constraint_last);
 	tv.tv_usec = 0;
-	constraint = gettime_from_timeval(&tv);
+	diff = fabs(val - gettime_from_timeval(&tv));
 
-	if (((val - constraint) > CONSTRAINT_MARGIN) ||
-	    ((constraint - val) > CONSTRAINT_MARGIN)) {
+	if (diff > CONSTRAINT_MARGIN) {
 		/* XXX get new constraint if too many errors happened */
 		if (conf->constraint_errors++ >
 		    (CONSTRAINT_ERROR_MARGIN * peer_cnt)) {
diff --git a/src/usr.sbin/ntpd/ntp.c b/src/usr.sbin/ntpd/ntp.c
index 7f7a42b7..25670f84 100644
--- a/src/usr.sbin/ntpd/ntp.c
+++ b/src/usr.sbin/ntpd/ntp.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: ntp.c,v 1.151 2019/05/29 18:48:33 otto Exp $ */
+/*	$OpenBSD: ntp.c,v 1.152 2019/05/30 13:42:19 otto Exp $ */
 
 /*
  * Copyright (c) 2003, 2004 Henning Brauer <henning@openbsd.org>
@@ -316,6 +316,11 @@ ntp_main(struct ntpd_conf *nconf, struct passwd *pw, int argc, char **argv)
 		    (peer_cnt == 0 && sensors_cnt == 0)))
 			priv_settime(0);	/* no good peers, don't wait */
 
+		TAILQ_FOREACH(cstr, &conf->constraints, entry) {
+			if (constraint_query(cstr) == -1)
+				continue;
+		}
+
 		if (ibuf_main->w.queued > 0)
 			pfd[PFD_PIPE_MAIN].events |= POLLOUT;
 		if (ibuf_dns->w.queued > 0)
@@ -330,15 +335,7 @@ ntp_main(struct ntpd_conf *nconf, struct passwd *pw, int argc, char **argv)
 		}
 		ctls = i;
 
-		TAILQ_FOREACH(cstr, &conf->constraints, entry) {
-			if (constraint_query(cstr) == -1)
-				continue;
-		}
-
 		now = getmonotime();
-		if (constraint_cnt)
-			nextaction = now + 1;
-
 		timeout = nextaction - now;
 		if (timeout < 0)
 			timeout = 0;