diff --git a/src/pmie/src/dstruct.c b/src/pmie/src/dstruct.c
index d440ea3..84d7a7b 100644
--- a/src/pmie/src/dstruct.c
+++ b/src/pmie/src/dstruct.c
@@ -191,11 +191,11 @@ unrealizenano(RealTime rt, struct timespec *ts)
 
 
 /* sleep until given RealTime */
-void
+int
 sleepTight(RealTime sched)
 {
     RealTime	delay;	/* interval to sleep */
-    int		sts;
+    int		sts = 0;
 #ifdef HAVE_WAITPID
     pid_t	pid;
 
@@ -219,14 +219,17 @@ sleepTight(RealTime sched)
 	struct timespec ts, tleft;
 
 	delay = sched - getReal();
+	if (delay < 0)
+	    return EINVAL;
+	
 	unrealizenano(delay, &ts);
-	for (;;) {	/* loop to catch early wakeup from nanosleep */
+	/* loop to catch early wakeup from nanosleep */
+	do {
 	    sts = nanosleep(&ts, &tleft);
-	    if (sts == 0 || (sts < 0 && errno != EINTR))
-		break;
 	    ts = tleft;
-	}
+	} while (sts < 0 && errno == EINTR);
     }
+    return sts == 0 ? sts : errno;
 }
 
 
diff --git a/src/pmie/src/dstruct.h b/src/pmie/src/dstruct.h
index 550afb7..5735dbd 100644
--- a/src/pmie/src/dstruct.h
+++ b/src/pmie/src/dstruct.h
@@ -76,7 +76,7 @@ void unrealize(RealTime, struct timeval *);
 
 RealTime getReal(void);			/* return current time */
 void reflectTime(RealTime);		/* update time vars to reflect now */
-void sleepTight(RealTime);		/* sleep until given RealTime */
+int sleepTight(RealTime);		/* sleep until given RealTime */
 
 
 /***********************************************************************
diff --git a/src/pmie/src/eval.c b/src/pmie/src/eval.c
index 7a0dbb8..5885805 100644
--- a/src/pmie/src/eval.c
+++ b/src/pmie/src/eval.c
@@ -729,7 +729,9 @@ findEval(Expr *x)
 void
 run(void)
 {
+    int		sts;
     Task	*t;
+    int		warp = 0;
 
     /* empty task queue */
     if (taskq == NULL)
@@ -751,8 +753,9 @@ run(void)
 	    now = t->retry;
 	    if (now > stop)
 		break;
-	    sleepTight(t->retry);
-	    enable(t);
+	    sts = sleepTight(t->retry);
+	    if (sts == 0)
+		enable(t);
 	    t->retry = waiting(t) ? now + RETRY : 0;
 	}
 	else {
@@ -760,8 +763,20 @@ run(void)
 	    if (now > stop)
 		break;
 	    reflectTime(t->delta);
-	    sleepTight(t->eval);
-	    eval(t);
+	    sts = sleepTight(t->eval);
+	    if (sts == 0) {
+		if (warp) {
+		    __pmNotifyErr(LOG_INFO,
+			"System clock warped forward by %ld seconds\n",
+			now - warp);
+		    warp = 0;
+		}
+		eval(t);
+	    } else if (sts == EINVAL) {
+		/* system clock jumped forward */
+		if (warp == 0)
+		    warp = now;
+	    }
 	    t->tick++;
 	    t->eval = t->epoch + t->tick * t->delta;
 	    if ((! t->retry) && waiting(t))