When checking whether we should scan the sensors again use <= rather

than < for the comparison.  Otherwise, if we don't do enough work
in the loop to advance the clock (for instance if the network is
down) we may end up calling poll() multiple times with no timeout,
racking up CPU time for no real reason.  OK bcook@

src/usr.sbin/ntpd/ntp.c

@@ -1,4 +1,4 @@
-/*	$OpenBSD: ntp.c,v 1.134 2015/07/18 00:59:00 bcook Exp $ */
+/*	$OpenBSD: ntp.c,v 1.135 2015/08/14 02:00:18 millert Exp $ */
 
 /*
  * Copyright (c) 2003, 2004 Henning Brauer <henning@openbsd.org>
@@ -315,7 +315,7 @@ ntp_main(int pipe_prnt[2], int fd_ctl, struct ntpd_conf *nconf,
 
 		if (!TAILQ_EMPTY(&conf->ntp_conf_sensors)) {
 			if (last_sensor_scan == 0 ||
-			    last_sensor_scan + SENSOR_SCAN_INTERVAL < getmonotime()) {
+			    last_sensor_scan + SENSOR_SCAN_INTERVAL <= getmonotime()) {
 				sensors_cnt = sensor_scan();
 				last_sensor_scan = getmonotime();
 			}