diff --git a/lib/libthr/thread/thr_private.h b/lib/libthr/thread/thr_private.h
index 3c4f9edd29a3..65e258d57b09 100644
--- a/lib/libthr/thread/thr_private.h
+++ b/lib/libthr/thread/thr_private.h
@@ -94,7 +94,7 @@
 	do { 							\
 		(dst)->tv_sec = (src)->tv_sec + (val)->tv_sec;	\
 		(dst)->tv_nsec = (src)->tv_nsec + (val)->tv_nsec; \
-		if ((dst)->tv_nsec > 1000000000) {		\
+		if ((dst)->tv_nsec >= 1000000000) {		\
 			(dst)->tv_sec++;			\
 			(dst)->tv_nsec -= 1000000000;		\
 		}						\