diff --git a/sys/kern/kern_clocksource.c b/sys/kern/kern_clocksource.c
--- a/sys/kern/kern_clocksource.c
+++ b/sys/kern/kern_clocksource.c
@@ -60,7 +60,7 @@
 int			cpu_disable_c3_sleep = 0; /* Timer dies in C3. */
 
 static void		setuptimer(void);
-static void		loadtimer(sbintime_t now, int first);
+static sbintime_t	loadtimer(int first);
 static int		doconfigtimer(void);
 static void		configtimer(int start);
 static int		round_freq(struct eventtimer *et, int freq);
@@ -219,7 +219,7 @@
 	if (!busy) {
 		state->idle = 0;
 		state->nextevent = t;
-		loadtimer(now, (fake == 2) &&
+		loadtimer((fake == 2) &&
 		    (timer->et_flags & ET_FLAGS_PERCPU));
 	}
 	ET_HW_UNLOCK(state);
@@ -371,22 +371,27 @@
 }
 
 /*
- * Load new value into hardware timer.
+ * Load new value into hardware timer and return
+ * the loaded time.
  */
-static void
-loadtimer(sbintime_t now, int start)
+static sbintime_t
+loadtimer(int start)
 {
+	sbintime_t now;
 	struct pcpu_state *state;
 	sbintime_t new;
 	sbintime_t *next;
 	uint64_t tmp;
-	int eq;
+	bool eq;
+
+	now = sbinuptime();
 
 	state = DPCPU_PTR(timerstate);
 	if (timer->et_flags & ET_FLAGS_PERCPU)
 		next = &state->nexttick;
 	else
 		next = &nexttick;
+
 	if (periodic) {
 		if (start) {
 			/*
@@ -406,13 +411,15 @@
 	} else {
 		new = getnextevent(state);
 		eq = (new == *next);
-		CTR3(KTR_SPARE2, "load:    next %d.%08x eq %d",
+		CTR5(KTR_SPARE2, "load:    now %d.%08x first in %d.%08x eq %d",
+		    (int)(now >> 32), (u_int)(now & 0xffffffff),
 		    (int)(new >> 32), (u_int)(new & 0xffffffff), eq);
 		if (!eq) {
 			*next = new;
 			et_start(timer, new - now, 0);
 		}
 	}
+	return (*next - now);
 }
 
 /*
@@ -447,9 +454,8 @@
 	state = DPCPU_PTR(timerstate);
 	switch (atomic_load_acq_int(&state->action)) {
 	case 1:
-		now = sbinuptime();
 		ET_HW_LOCK(state);
-		loadtimer(now, 1);
+		loadtimer(1);
 		ET_HW_UNLOCK(state);
 		state->handle = 0;
 		atomic_store_rel_int(&state->action, 0);
@@ -481,14 +487,13 @@
 	struct pcpu_state *state;
 	int cpu;
 
-	if (start) {
+	if (start)
 		setuptimer();
-		now = sbinuptime();
-	} else
-		now = 0;
 	critical_enter();
 	ET_HW_LOCK(DPCPU_PTR(timerstate));
 	if (start) {
+		now = sbinuptime();
+
 		/* Initialize time machine parameters. */
 		next = now + timerperiod;
 		if (periodic)
@@ -520,7 +525,7 @@
 		}
 		busy = 0;
 		/* Start global timer or per-CPU timer of this CPU. */
-		loadtimer(now, 1);
+		loadtimer(1);
 	} else {
 		busy = 1;
 		/* Stop global timer or per-CPU timer of this CPU. */
@@ -756,7 +761,7 @@
 sbintime_t
 cpu_idleclock(void)
 {
-	sbintime_t now, t;
+	sbintime_t t;
 	struct pcpu_state *state;
 
 	if (idletick || busy ||
@@ -768,19 +773,17 @@
 		return (-1);
 	state = DPCPU_PTR(timerstate);
 	ET_HW_LOCK(state);
-	if (periodic)
-		now = state->now;
-	else
-		now = sbinuptime();
-	CTR2(KTR_SPARE2, "idle:    now  %d.%08x",
-	    (int)(now >> 32), (u_int)(now & 0xffffffff));
 	t = getnextcpuevent(state, 1);
+	CTR2(KTR_SPARE2, "idle:    next  %d.%08x",
+	    (int)(t >> 32), (u_int)(t & 0xffffffff));
 	state->idle = 1;
 	state->nextevent = t;
-	if (!periodic)
-		loadtimer(now, 0);
+	if (periodic)
+		t -= state->now;
+	else
+		t = loadtimer(0);
 	ET_HW_UNLOCK(state);
-	return (MAX(t - now, 0));
+	return (MAX(t, 0));
 }
 
 /*
@@ -866,7 +869,7 @@
 		goto done;
 	/* If timer is global or of the current CPU -- reprogram it. */
 	if ((timer->et_flags & ET_FLAGS_PERCPU) == 0 || cpu == curcpu) {
-		loadtimer(sbinuptime(), 0);
+		loadtimer(0);
 done:
 		ET_HW_UNLOCK(state);
 		return;