diff --git a/xen/common/timer.c b/xen/common/timer.c
index 1895a78..744bc66 100644
--- a/xen/common/timer.c
+++ b/xen/common/timer.c
@@ -25,7 +25,7 @@
 #include <asm/desc.h>
 #include <asm/atomic.h>
 
-/* We program the time hardware this far behind the closest deadline. */
+/* We fire events up to this amount early. */
 static unsigned int timer_slop __read_mostly = 50000; /* 50 us */
 integer_param("timer_slop", timer_slop);
 
@@ -463,14 +463,14 @@ static void timer_softirq_action(void)
 
     /* Execute ready heap timers. */
     while ( (GET_HEAP_SIZE(heap) != 0) &&
-            ((t = heap[1])->expires < now) )
+            ((t = heap[1])->expires < (now + timer_slop) ) )
     {
         remove_from_heap(heap, t);
         execute_timer(ts, t);
     }
 
     /* Execute ready list timers. */
-    while ( ((t = ts->list) != NULL) && (t->expires < now) )
+    while ( ((t = ts->list) != NULL) && (t->expires < (now + timer_slop) ) )
     {
         ts->list = t->list_next;
         execute_timer(ts, t);
@@ -493,7 +493,7 @@ static void timer_softirq_action(void)
     if ( (ts->list != NULL) && (ts->list->expires < deadline) )
         deadline = ts->list->expires;
     this_cpu(timer_deadline) =
-        (deadline == STIME_MAX) ? 0 : deadline + timer_slop;
+        (deadline == STIME_MAX) ? 0 : deadline;
 
     if ( !reprogram_timer(this_cpu(timer_deadline)) )
         raise_softirq(TIMER_SOFTIRQ);