Index: source/lib/timer.cpp
===================================================================
--- source/lib/timer.cpp
+++ source/lib/timer.cpp
@@ -79,7 +79,7 @@
 #if OS_WIN
 	ENSURE(QueryPerformanceCounter(&start));
 #elif HAVE_CLOCK_GETTIME
-	(void)clock_gettime(CLOCK_REALTIME, &start);
+	(void)clock_gettime(CLOCK_MONOTONIC, &start);
 #elif HAVE_GETTIMEOFDAY
 	gettimeofday(&start, 0);
 #endif
@@ -110,7 +110,7 @@
 #elif HAVE_CLOCK_GETTIME
 	ENSURE(start.tv_sec || start.tv_nsec);	// must have called timer_LatchStartTime first
 	struct timespec cur;
-	(void)clock_gettime(CLOCK_REALTIME, &cur);
+	(void)clock_gettime(CLOCK_MONOTONIC, &cur);
 	t = (cur.tv_sec - start.tv_sec) + (cur.tv_nsec - start.tv_nsec)*1e-9;
 #elif HAVE_GETTIMEOFDAY
 	ENSURE(start.tv_sec || start.tv_usec);	// must have called timer_LatchStartTime first
@@ -134,7 +134,7 @@
 	resolution = 1.0 / static_cast<double>(frequency.QuadPart);
 #elif HAVE_CLOCK_GETTIME
 	struct timespec ts;
-	if(clock_getres(CLOCK_REALTIME, &ts) == 0)
+	if(clock_getres(CLOCK_MONOTONIC, &ts) == 0)
 		resolution = ts.tv_nsec * 1e-9;
 #else
 	const double t0 = timer_Time();