Better support for poor os monotonic sources

9 files changed, 431 insertions, 246 deletions

diff --git a/erts/emulator/Makefile.in b/erts/emulator/Makefile.in
index 560cab396d..658f1b861a 100644
--- a/erts/emulator/Makefile.in
+++ b/erts/emulator/Makefile.in
@@ -898,7 +898,8 @@ OS_OBJS +=	$(OBJDIR)/erl_mseg.o \
 		$(OBJDIR)/erl_mmap.o \
 		$(OBJDIR)/erl_$(ERLANG_OSTYPE)_sys_ddll.o \
 		$(OBJDIR)/erl_mtrace_sys_wrap.o \
-		$(OBJDIR)/erl_sys_common_misc.o
+		$(OBJDIR)/erl_sys_common_misc.o \
+		$(OBJDIR)/erl_os_monotonic_time_extender.o
 
 HIPE_ARCH64_OBJS=$(OBJDIR)/hipe_bif64.o
 
diff --git a/erts/emulator/beam/erl_time.h b/erts/emulator/beam/erl_time.h
index 924b0b6091..35a1442dbd 100644
--- a/erts/emulator/beam/erl_time.h
+++ b/erts/emulator/beam/erl_time.h
@@ -219,6 +219,10 @@ erts_time_unit_conversion(Uint64 value,
  * it is assumed (and need) to be a power of 10.
  */
 
+#if ERTS_COMPILE_TIME_MONOTONIC_TIME_UNIT < 1000*1000
+#  error Compile time time unit needs to be at least 1000000
+#endif
+
 #define ERTS_MONOTONIC_TIME_UNIT \
     ((ErtsMonotonicTime) ERTS_COMPILE_TIME_MONOTONIC_TIME_UNIT)
 
@@ -248,19 +252,6 @@ erts_time_unit_conversion(Uint64 value,
 #define ERTS_USEC_TO_MONOTONIC__(USEC) ((ErtsMonotonicTime) (USEC))
 #define ERTS_NSEC_TO_MONOTONIC__(NSEC) (((ErtsMonotonicTime) (NSEC))/1000)
 
-#elif ERTS_COMPILE_TIME_MONOTONIC_TIME_UNIT == 1000
-/* Milli-second time unit */
-
-#define ERTS_MONOTONIC_TO_SEC__(MSEC) ((USEC)/(1000))
-#define ERTS_MONOTONIC_TO_MSEC__(MSEC) (MSEC)
-#define ERTS_MONOTONIC_TO_USEC__(MSEC) ((MSEC)*1000)
-#define ERTS_MONOTONIC_TO_NSEC__(MSEC) ((MSEC)*(1000*1000))
-
-#define ERTS_SEC_TO_MONOTONIC__(SEC) (((ErtsMonotonicTime) (SEC))*1000)
-#define ERTS_MSEC_TO_MONOTONIC__(MSEC) ((ErtsMonotonicTime) (MSEC))
-#define ERTS_USEC_TO_MONOTONIC__(USEC) (((ErtsMonotonicTime) (USEC))/1000)
-#define ERTS_NSEC_TO_MONOTONIC__(NSEC) (((ErtsMonotonicTime) (NSEC))/(1000*1000))
-
 #else
 #error Missing implementation for monotonic time unit
 #endif
diff --git a/erts/emulator/beam/erl_time_sup.c b/erts/emulator/beam/erl_time_sup.c
index b809fa8316..d961fae81a 100644
--- a/erts/emulator/beam/erl_time_sup.c
+++ b/erts/emulator/beam/erl_time_sup.c
@@ -21,6 +21,8 @@
  * Support routines for the time
  */
 
+/* #define ERTS_TIME_CORRECTION_PRINT */
+
 #ifdef HAVE_CONFIG_H
 #  include "config.h"
 #endif
@@ -75,12 +77,12 @@ schedule_send_time_offset_changed_notifications(ErtsMonotonicTime new_offset);
 
 #else /* ARCH_64 */
 
-#if ERTS_COMPILE_TIME_MONOTONIC_TIME_UNIT <= 1000*1000
+#if ERTS_COMPILE_TIME_MONOTONIC_TIME_UNIT <= 10*1000*1000
 
 /*
  * Using micro second time unit or lower. Start at zero since
  * time will remain an immediate for a very long time anyway
- * (18279 years in the micro second case)...
+ * (1827 years in the 10 micro second case)...
  */
 #define ERTS_MONOTONIC_TIME_START ((ErtsMonotonicTime) 0)
 
@@ -99,11 +101,16 @@ schedule_send_time_offset_changed_notifications(ErtsMonotonicTime new_offset);
 
 #endif /* ARCH_64 */
 
-#define ERTS_MONOTONIC_OFFSET_NATIVE ERTS_MONOTONIC_TIME_START
-#define ERTS_MONOTONIC_OFFSET_NSEC ERTS_MONOTONIC_TO_NSEC__(ERTS_MONOTONIC_TIME_START)
-#define ERTS_MONOTONIC_OFFSET_USEC ERTS_MONOTONIC_TO_USEC__(ERTS_MONOTONIC_TIME_START)
-#define ERTS_MONOTONIC_OFFSET_MSEC ERTS_MONOTONIC_TO_MSEC__(ERTS_MONOTONIC_TIME_START)
-#define ERTS_MONOTONIC_OFFSET_SEC ERTS_MONOTONIC_TO_SEC__(ERTS_MONOTONIC_TIME_START)
+#define ERTS_MONOTONIC_OFFSET_NATIVE \
+    (ERTS_MONOTONIC_TIME_START - ERTS_MONOTONIC_TIME_UNIT)
+#define ERTS_MONOTONIC_OFFSET_NSEC					\
+    ERTS_MONOTONIC_TO_NSEC__(ERTS_MONOTONIC_OFFSET_NATIVE)
+#define ERTS_MONOTONIC_OFFSET_USEC					\
+    ERTS_MONOTONIC_TO_USEC__(ERTS_MONOTONIC_OFFSET_NATIVE)
+#define ERTS_MONOTONIC_OFFSET_MSEC					\
+    ERTS_MONOTONIC_TO_MSEC__(ERTS_MONOTONIC_OFFSET_NATIVE)
+#define ERTS_MONOTONIC_OFFSET_SEC					\
+    ERTS_MONOTONIC_TO_SEC__(ERTS_MONOTONIC_OFFSET_NATIVE)
 
 #else /* ERTS_COMPILE_TIME_MONOTONIC_TIME_UNIT */
 
@@ -120,25 +127,6 @@ schedule_send_time_offset_changed_notifications(ErtsMonotonicTime new_offset);
 
 #endif /* ERTS_COMPILE_TIME_MONOTONIC_TIME_UNIT */
 
-#define ERTS_MONOTONIC_TO_SYS_TIME_VAL(TVP, MT)				\
-    do {								\
-	ErtsMonotonicTime sec__, usec__;				\
-	sec__ = ERTS_MONOTONIC_TO_SEC((MT));				\
-	usec__ = ERTS_MONOTONIC_TO_USEC((MT)) - sec__*1000000;		\
-	ASSERT(usec__ < 1000000);					\
-	(TVP)->tv_sec = sec__;						\
-	(TVP)->tv_usec = usec__;					\
-    } while (0)
-
-#define ERTS_MAX_SYSTEM_TIME_DIFF ERTS_MSEC_TO_MONOTONIC(10)
-#define ERTS_SYSTEM_TIME_DIFF_EXCEED_LIMIT(ESYSTIME, OSSYSTIME)		\
-    (((Uint64) (ESYSTIME)) - (((Uint64) (OSSYSTIME))			\
-			      - ERTS_MAX_SYSTEM_TIME_DIFF)		\
-     > 2*ERTS_MAX_SYSTEM_TIME_DIFF)
-
-#define ERTS_TIME_CORRECTION_LARGE_ADJ_DIFF (ERTS_MAX_SYSTEM_TIME_DIFF/2)
-#define ERTS_TIME_CORRECTION_SMALL_ADJ_DIFF ERTS_USEC_TO_MONOTONIC(500)
-
 struct time_sup_read_only__ {
     ErtsMonotonicTime (*get_time)(void);
     int correction;
@@ -150,6 +138,7 @@ struct time_sup_read_only__ {
     char *os_monotonic_clock_id;
     int os_monotonic_locked;
     Uint64 os_monotonic_resolution;
+    Uint64 os_monotonic_extended;
 #endif
 #if !ERTS_COMPILE_TIME_MONOTONIC_TIME_UNIT
     ErtsMonotonicTime start;
@@ -161,6 +150,10 @@ struct time_sup_read_only__ {
 	ErtsMonotonicTime sec;
     } start_offset;
 #endif
+    struct {
+	ErtsMonotonicTime large_diff;
+	ErtsMonotonicTime small_diff;
+    } adj;
 };
 
 typedef struct {
@@ -338,13 +331,77 @@ static ErtsMonotonicTime get_corrected_time(void)
     return calc_corrected_erl_mtime(os_mtime, cip, NULL);
 }
 
+#ifdef ERTS_TIME_CORRECTION_PRINT
+
+static ERTS_INLINE void
+print_correction(int change,
+		 ErtsMonotonicTime sdiff,
+		 ErtsMonotonicTime old_ecorr,
+		 ErtsMonotonicTime old_dcorr,
+		 ErtsMonotonicTime new_ecorr,
+		 ErtsMonotonicTime new_dcorr,
+		 Uint tmo)
+{
+    ErtsMonotonicTime usec_sdiff;
+    if (sdiff < 0)
+	usec_sdiff = -1*ERTS_MONOTONIC_TO_USEC(-1*sdiff);
+    else
+	usec_sdiff = ERTS_MONOTONIC_TO_USEC(sdiff);
+
+    if (!change)
+	fprintf(stderr,
+		"sdiff = %lld usec : [ec=%lld ppm, dc=%lld ppm] : "
+		"tmo = %lld msec\r\n",
+		(long long) usec_sdiff,
+		(long long) (1000000*old_ecorr) / ERTS_TCORR_ERR_UNIT,
+		(long long) (1000000*old_dcorr) / ERTS_MONOTONIC_TIME_UNIT,
+		(long long) tmo);
+    else
+	fprintf(stderr,
+		"sdiff = %lld usec : [ec=%lld ppm, dc=%lld ppm] "
+		"-> [ec=%lld ppm, dc=%lld ppm] : tmo = %lld msec\r\n",
+		(long long) usec_sdiff,
+		(long long) (1000000*old_ecorr) / ERTS_TCORR_ERR_UNIT,
+		(long long) (1000000*old_dcorr) / ERTS_MONOTONIC_TIME_UNIT,
+		(long long) (1000000*new_ecorr) / ERTS_TCORR_ERR_UNIT,
+		(long long) (1000000*new_dcorr) / ERTS_MONOTONIC_TIME_UNIT,
+		(long long) tmo);
+
+}
+
+#endif
+
 static void
 check_time_correction(void *unused)
 {
+#ifndef ERTS_TIME_CORRECTION_PRINT
+#  define ERTS_PRINT_CORRECTION
+#else
+#  ifdef ERTS_HAVE_CORRECTED_OS_MONOTONIC
+#    define ERTS_PRINT_CORRECTION		\
+    print_correction(set_new_correction,	\
+		     sdiff,			\
+		     cip->correction.error,	\
+		     0,				\
+		     new_correction.error,	\
+		     0,				\
+		     timeout)
+#  else
+#    define ERTS_PRINT_CORRECTION		\
+    print_correction(set_new_correction,	\
+		     sdiff,			\
+		     cip->correction.error,	\
+		     cip->correction.drift,	\
+		     new_correction.error,	\
+		     new_correction.drift,	\
+		     timeout)
+#  endif
+#endif
     ErtsMonotonicCorrectionData cdata;
     ErtsMonotonicCorrection new_correction;
     ErtsMonotonicCorrectionInstance *cip;
-    ErtsMonotonicTime mdiff, sdiff, os_mtime, erl_mtime, os_stime, erl_stime, time_offset;
+    ErtsMonotonicTime mdiff, sdiff, os_mtime, erl_mtime, os_stime,
+	erl_stime, time_offset;
     Uint timeout;
     SysTimeval tod;
     int set_new_correction, begin_short_intervals = 0;
@@ -377,8 +434,8 @@ check_time_correction(void *unused)
     new_correction = cip->correction;
     
     if (time_sup.r.o.warp_mode == ERTS_MULTI_TIME_WARP_MODE
-	&& (sdiff < -2*ERTS_TIME_CORRECTION_SMALL_ADJ_DIFF
-	    || 2*ERTS_TIME_CORRECTION_SMALL_ADJ_DIFF < sdiff)) {
+	&& (sdiff < -2*time_sup.r.o.adj.small_diff
+	    || 2*time_sup.r.o.adj.small_diff < sdiff)) {
 	/* System time diff exeeded limits; change time offset... */
 	time_offset -= sdiff;
 	sdiff = 0;
@@ -393,16 +450,16 @@ check_time_correction(void *unused)
 	}
     }
     else if (cdata.curr.correction.error == 0) {
-	if (sdiff < -ERTS_TIME_CORRECTION_SMALL_ADJ_DIFF) {
+	if (sdiff < -time_sup.r.o.adj.small_diff) {
 	    set_new_correction = 1;
-	    if (sdiff < -ERTS_TIME_CORRECTION_LARGE_ADJ_DIFF)
+	    if (sdiff < -time_sup.r.o.adj.large_diff)
 		new_correction.error = ERTS_TCORR_ERR_LARGE_ADJ;
 	    else
 		new_correction.error = ERTS_TCORR_ERR_SMALL_ADJ;
 	}
-	else if (sdiff > ERTS_TIME_CORRECTION_SMALL_ADJ_DIFF) {
+	else if (sdiff > time_sup.r.o.adj.small_diff) {
 	    set_new_correction = 1;
-	    if (sdiff > ERTS_TIME_CORRECTION_LARGE_ADJ_DIFF)
+	    if (sdiff > time_sup.r.o.adj.large_diff)
 		new_correction.error = -ERTS_TCORR_ERR_LARGE_ADJ;
 	    else
 		new_correction.error = -ERTS_TCORR_ERR_SMALL_ADJ;
@@ -414,16 +471,16 @@ check_time_correction(void *unused)
     else if (cdata.curr.correction.error > 0) {
 	if (sdiff < 0) {
 	    if (cdata.curr.correction.error == ERTS_TCORR_ERR_LARGE_ADJ
-		|| -ERTS_TIME_CORRECTION_LARGE_ADJ_DIFF <= sdiff)
+		|| -time_sup.r.o.adj.large_diff <= sdiff)
 		set_new_correction = 0;
 	    else {
 		new_correction.error = ERTS_TCORR_ERR_LARGE_ADJ;
 		set_new_correction = 1;
 	    }
 	}
-	else if (sdiff > ERTS_TIME_CORRECTION_SMALL_ADJ_DIFF) {
+	else if (sdiff > time_sup.r.o.adj.small_diff) {
 	    set_new_correction = 1;
-	    if (sdiff > ERTS_TIME_CORRECTION_LARGE_ADJ_DIFF)
+	    if (sdiff > time_sup.r.o.adj.large_diff)
 		new_correction.error = -ERTS_TCORR_ERR_LARGE_ADJ;
 	    else
 		new_correction.error = -ERTS_TCORR_ERR_SMALL_ADJ;
@@ -436,7 +493,7 @@ check_time_correction(void *unused)
     else /* if (cdata.curr.correction.error < 0) */ { 
 	if (0 < sdiff) {
 	    if (cdata.curr.correction.error == -ERTS_TCORR_ERR_LARGE_ADJ
-		|| sdiff <= ERTS_TIME_CORRECTION_LARGE_ADJ_DIFF)
+		|| sdiff <= time_sup.r.o.adj.large_diff)
 		set_new_correction = 0;
 	    else {
 		new_correction.error = -ERTS_TCORR_ERR_LARGE_ADJ;
@@ -444,9 +501,9 @@ check_time_correction(void *unused)
 	    }
 	    set_new_correction = 0;
 	}
-	else if (sdiff < -ERTS_TIME_CORRECTION_SMALL_ADJ_DIFF) {
+	else if (sdiff < -time_sup.r.o.adj.small_diff) {
 	    set_new_correction = 1;
-	    if (sdiff < -ERTS_TIME_CORRECTION_LARGE_ADJ_DIFF)
+	    if (sdiff < -time_sup.r.o.adj.large_diff)
 		new_correction.error = ERTS_TCORR_ERR_LARGE_ADJ;
 	    else
 		new_correction.error = ERTS_TCORR_ERR_SMALL_ADJ;
@@ -475,11 +532,13 @@ check_time_correction(void *unused)
 	    mtime_acc = ddp->acc.mon;
 	    stime_acc = ddp->acc.sys;
 
-	    avg_drift_adj = ((stime_acc - mtime_acc)*ERTS_MONOTONIC_TIME_UNIT) / mtime_acc;
+	    avg_drift_adj = (((stime_acc - mtime_acc)*ERTS_MONOTONIC_TIME_UNIT)
+			     / mtime_acc);
 
 	    mtime_diff = os_mtime - old_os_mtime;
 	    stime_diff = os_stime - old_os_stime;
-	    drift_adj = ((stime_diff - mtime_diff)*ERTS_MONOTONIC_TIME_UNIT) / mtime_diff;
+	    drift_adj = (((stime_diff - mtime_diff)*ERTS_MONOTONIC_TIME_UNIT)
+			 / mtime_diff);
 	    
 	    ix++;
 	    if (ix >= ERTS_DRIFT_INTERVALS)
@@ -499,10 +558,11 @@ check_time_correction(void *unused)
 	    ddp->acc.sys = stime_acc;
 
 	    /*
-	     * If calculated drift adjustment is if off by more than 20% from the
-	     * average drift we interpret this as a discontinous leap in system
-	     * time and ignore it. If it actually is a change in drift we will
-	     * later detect this when the average drift change.
+	     * If calculated drift adjustment is if off by more than 20%
+	     * from the average drift we interpret this as a discontinous
+	     * leap in system time and ignore it. If it actually is a
+	     * change in drift we will later detect this when the average
+	     * drift change.
 	     */
 	    drift_adj_diff = avg_drift_adj - drift_adj;
 	    if (drift_adj_diff < -ERTS_TIME_DRIFT_MAX_ADJ_DIFF
@@ -512,7 +572,8 @@ check_time_correction(void *unused)
 	    }
 	    else {
 		if (ddp->dirty_counter <= 0) {
-		    drift_adj = ((stime_acc - mtime_acc)*ERTS_MONOTONIC_TIME_UNIT) / mtime_acc;
+		    drift_adj = ((stime_acc - mtime_acc)
+				 *ERTS_MONOTONIC_TIME_UNIT) / mtime_acc;
 		}
 		if (ddp->dirty_counter >= 0) {
 		    if (ddp->dirty_counter == 0) {
@@ -573,7 +634,9 @@ check_time_correction(void *unused)
 	&& time_sup.inf.c.parmon.cdata.short_check_interval) {
 	timeout = ERTS_MONOTONIC_TO_MSEC(ERTS_SHORT_TIME_CORRECTION_CHECK);
     }
-    
+
+    ERTS_PRINT_CORRECTION;
+
     if (set_new_correction) {
 	erts_smp_rwmtx_rwlock(&time_sup.inf.c.parmon.rwmtx);
 
@@ -610,6 +673,8 @@ check_time_correction(void *unused)
 		   NULL,
 		   NULL,
 		   timeout);
+
+#undef ERTS_PRINT_CORRECTION
 }
 
 #ifndef ERTS_HAVE_CORRECTED_OS_MONOTONIC
@@ -618,7 +683,8 @@ static void
 init_check_time_correction(void *unused)
 {
     ErtsMonotonicDriftData *ddp;
-    ErtsMonotonicTime old_mtime, old_stime, mtime, stime, mtime_diff, stime_diff;
+    ErtsMonotonicTime old_mtime, old_stime, mtime, stime, mtime_diff,
+	stime_diff;
     int ix;
     SysTimeval tod;
 
@@ -690,6 +756,7 @@ static void
 late_init_time_correction(void)
 {
     if (time_sup.inf.c.finalized_offset) {
+
 	erts_init_timer(&time_sup.inf.c.parmon.timer);
 	erts_set_timer(&time_sup.inf.c.parmon.timer,
 #ifndef ERTS_HAVE_CORRECTED_OS_MONOTONIC
@@ -792,6 +859,8 @@ void erts_init_sys_time_sup(void)
 	= sys_init_time_res.os_monotonic_info.locked_use;
     time_sup.r.o.os_monotonic_resolution
 	= sys_init_time_res.os_monotonic_info.resolution;
+    time_sup.r.o.os_monotonic_extended
+	= sys_init_time_res.os_monotonic_info.extended;
 #endif
 }
 
@@ -799,7 +868,7 @@ int
 erts_init_time_sup(int time_correction, ErtsTimeWarpMode time_warp_mode)
 {
 #if !ERTS_COMPILE_TIME_MONOTONIC_TIME_UNIT
-    ErtsMonotonicTime abs_start;
+    ErtsMonotonicTime abs_native_offset, native_offset;
 #endif
 
     ASSERT(ERTS_MONOTONIC_TIME_MIN < ERTS_MONOTONIC_TIME_MAX);
@@ -822,36 +891,42 @@ erts_init_time_sup(int time_correction, ErtsTimeWarpMode time_warp_mode)
     time_sup.r.o.start /= ERTS_MONOTONIC_TIME_UNIT;
     time_sup.r.o.start *= ERTS_MONOTONIC_TIME_UNIT;
     time_sup.r.o.start += ERTS_MONOTONIC_TIME_UNIT;
-    abs_start = time_sup.r.o.start;
+    native_offset = time_sup.r.o.start - ERTS_MONOTONIC_TIME_UNIT;
+    native_offset = native_offset;
 #else /* ARCH_64 */
-    if (ERTS_MONOTONIC_TIME_UNIT <= 1000*1000)
-	abs_start = time_sup.r.o.start = 0;
+    if (ERTS_MONOTONIC_TIME_UNIT <= 10*1000*1000) {
+	time_sup.r.o.start = 0;
+	native_offset = -ERTS_MONOTONIC_TIME_UNIT;
+	abs_native_offset = ERTS_MONOTONIC_TIME_UNIT;
+    }
     else {
 	time_sup.r.o.start = ((ErtsMonotonicTime) MIN_SMALL);
 	time_sup.r.o.start /= ERTS_MONOTONIC_TIME_UNIT;
 	time_sup.r.o.start *= ERTS_MONOTONIC_TIME_UNIT;
-	abs_start = -1*time_sup.r.o.start;
+	native_offset = time_sup.r.o.start - ERTS_MONOTONIC_TIME_UNIT;
+	abs_native_offset = -1*native_offset;
     }
 #endif
 
-    time_sup.r.o.start_offset.native = time_sup.r.o.start;
+    time_sup.r.o.start_offset.native = (time_sup.r.o.start
+					- ERTS_MONOTONIC_TIME_UNIT);
     time_sup.r.o.start_offset.nsec = (ErtsMonotonicTime)
-	erts_time_unit_conversion((Uint64) abs_start,
+	erts_time_unit_conversion((Uint64) abs_native_offset,
 				  (Uint32) ERTS_MONOTONIC_TIME_UNIT,
 				  (Uint32) 1000*1000*1000);
     time_sup.r.o.start_offset.usec = (ErtsMonotonicTime)
-	erts_time_unit_conversion((Uint64) abs_start,
+	erts_time_unit_conversion((Uint64) abs_native_offset,
 				  (Uint32) ERTS_MONOTONIC_TIME_UNIT,
 				  (Uint32) 1000*1000);
     time_sup.r.o.start_offset.msec = (ErtsMonotonicTime)
-	erts_time_unit_conversion((Uint64) abs_start,
+	erts_time_unit_conversion((Uint64) abs_native_offset,
 				  (Uint32) ERTS_MONOTONIC_TIME_UNIT,
 				  (Uint32) 1000);
     time_sup.r.o.start_offset.sec = (ErtsMonotonicTime)
-	erts_time_unit_conversion((Uint64) abs_start,
+	erts_time_unit_conversion((Uint64) abs_native_offset,
 				  (Uint32) ERTS_MONOTONIC_TIME_UNIT,
 				  (Uint32) 1);
-    if (time_sup.r.o.start < 0) {
+    if (native_offset < 0) {
 	time_sup.r.o.start_offset.nsec *= -1;
 	time_sup.r.o.start_offset.usec *= -1;
 	time_sup.r.o.start_offset.msec *= -1;
@@ -860,6 +935,26 @@ erts_init_time_sup(int time_correction, ErtsTimeWarpMode time_warp_mode)
 
 #endif
 
+    time_sup.r.o.adj.large_diff = erts_time_sup__.r.o.monotonic_time_unit;
+    time_sup.r.o.adj.large_diff *= 50;
+    time_sup.r.o.adj.large_diff /= time_sup.r.o.os_monotonic_resolution;
+    if (time_sup.r.o.adj.large_diff < ERTS_MSEC_TO_MONOTONIC(5))
+	time_sup.r.o.adj.large_diff = ERTS_MSEC_TO_MONOTONIC(5);
+    time_sup.r.o.adj.small_diff = time_sup.r.o.adj.large_diff/10;
+
+#ifdef ERTS_TIME_CORRECTION_PRINT
+    fprintf(stderr, "start         = %lld\n\r", (long long) ERTS_MONOTONIC_TIME_START);
+    fprintf(stderr, "native offset = %lld\n\r", (long long) ERTS_MONOTONIC_OFFSET_NATIVE);
+    fprintf(stderr, "nsec offset   = %lld\n\r", (long long) ERTS_MONOTONIC_OFFSET_NSEC);
+    fprintf(stderr, "usec offset   = %lld\n\r", (long long) ERTS_MONOTONIC_OFFSET_USEC);
+    fprintf(stderr, "msec offset   = %lld\n\r", (long long) ERTS_MONOTONIC_OFFSET_MSEC);
+    fprintf(stderr, "sec offset    = %lld\n\r", (long long) ERTS_MONOTONIC_OFFSET_SEC);
+    fprintf(stderr, "large diff    = %lld usec\r\n",
+	    (long long) ERTS_MONOTONIC_TO_USEC(time_sup.r.o.adj.large_diff));
+    fprintf(stderr, "small diff    = %lld usec\r\n",
+	    (long long) ERTS_MONOTONIC_TO_USEC(time_sup.r.o.adj.small_diff));
+#endif
+
     if (ERTS_MONOTONIC_TIME_UNIT < ERTS_CLKTCK_RESOLUTION)
 	ERTS_INTERNAL_ERROR("Too small monotonic time time unit");
 
@@ -878,6 +973,7 @@ erts_init_time_sup(int time_correction, ErtsTimeWarpMode time_warp_mode)
 	time_sup.r.o.moffset = -1*time_sup.inf.c.minit;
 	offset = ERTS_SEC_TO_MONOTONIC(time_sup.inf.c.inittv.tv_sec);
 	offset += ERTS_USEC_TO_MONOTONIC(time_sup.inf.c.inittv.tv_usec);
+	offset -= ERTS_MONOTONIC_TIME_UNIT;
 	init_time_offset(offset);
 
 	rwmtx_opts.type = ERTS_SMP_RWMTX_TYPE_EXTREMELY_FREQUENT_READ;
@@ -897,7 +993,7 @@ erts_init_time_sup(int time_correction, ErtsTimeWarpMode time_warp_mode)
 	cdatap->curr.correction.drift = 0;
 #endif
 	cdatap->curr.correction.error = 0;
-	cdatap->curr.erl_mtime = 0;
+	cdatap->curr.erl_mtime = ERTS_MONOTONIC_TIME_UNIT;
 	cdatap->curr.os_mtime = time_sup.inf.c.minit;
 	cdatap->last_check = time_sup.inf.c.minit;
 	cdatap->short_check_interval = ERTS_INIT_SHORT_INTERVAL_COUNTER;
@@ -910,9 +1006,10 @@ erts_init_time_sup(int time_correction, ErtsTimeWarpMode time_warp_mode)
     {
 	ErtsMonotonicTime stime, offset;
 	time_sup.r.o.get_time = get_not_corrected_time;
+	sys_gettimeofday(&time_sup.inf.c.inittv);
 	stime = ERTS_SEC_TO_MONOTONIC(time_sup.inf.c.inittv.tv_sec);
-	stime += ERTS_USEC_TO_MONOTONIC(time_sup.inf.c.inittv.tv_usec);
-	offset = stime;
+ 	stime += ERTS_USEC_TO_MONOTONIC(time_sup.inf.c.inittv.tv_usec);
+	offset = stime - ERTS_MONOTONIC_TIME_UNIT;
 	time_sup.inf.c.not_corrected_moffset = offset;
 	init_time_offset(offset);
 	time_sup.f.c.last_not_corrected_time = 0;
@@ -937,6 +1034,7 @@ erts_late_init_time_sup(void)
     if (time_sup.r.o.get_time == get_corrected_time)
 	late_init_time_correction();
 #endif
+    erts_late_sys_init_time();
 }
 
 ErtsTimeWarpMode erts_time_warp_mode(void)
@@ -1737,7 +1835,7 @@ make_time_val(Process *c_p, ErtsMonotonicTime time_val)
 Eterm
 erts_get_monotonic_start_time(struct process *c_p)
 {
-    return make_time_val(c_p, ERTS_MONOTONIC_OFFSET_NATIVE);
+    return make_time_val(c_p, ERTS_MONOTONIC_TIME_START);
 }
 
 static Eterm
@@ -1747,8 +1845,8 @@ bld_monotonic_time_source(Uint **hpp, Uint *szp, Sint64 os_mtime)
     return NIL;
 #else
     int i = 0;
-    Eterm k[5];
-    Eterm v[5];
+    Eterm k[6];
+    Eterm v[6];
 
     if (time_sup.r.o.os_monotonic_disable)
 	return NIL;
@@ -1761,10 +1859,11 @@ bld_monotonic_time_source(Uint **hpp, Uint *szp, Sint64 os_mtime)
 	v[i++] = erts_bld_atom(hpp, szp, time_sup.r.o.os_monotonic_clock_id);
     }
 
-    if (time_sup.r.o.os_monotonic_resolution) {
-	k[i] = erts_bld_atom(hpp, szp, "resolution");
-	v[i++] = erts_bld_uint64(hpp, szp, time_sup.r.o.os_monotonic_resolution);
-    }
+    k[i] = erts_bld_atom(hpp, szp, "resolution");
+    v[i++] = erts_bld_uint64(hpp, szp, time_sup.r.o.os_monotonic_resolution);
+
+    k[i] = erts_bld_atom(hpp, szp, "extended");
+    v[i++] = time_sup.r.o.os_monotonic_extended ? am_yes : am_no;
 
     k[i] = erts_bld_atom(hpp, szp, "parallel");
     v[i++] = time_sup.r.o.os_monotonic_locked ? am_no : am_yes;
diff --git a/erts/emulator/beam/sys.h b/erts/emulator/beam/sys.h
index a108e819c6..d83bdf8d31 100644
--- a/erts/emulator/beam/sys.h
+++ b/erts/emulator/beam/sys.h
@@ -692,6 +692,7 @@ typedef struct {
 	char *func;
 	char *clock_id;
 	int locked_use;
+	int extended;
     } os_monotonic_info;
 } ErtsSysInitTimeResult;
 
@@ -700,6 +701,7 @@ typedef struct {
 
 extern void erts_init_sys_time_sup(void);
 extern void sys_init_time(ErtsSysInitTimeResult *);
+extern void erts_late_sys_init_time(void);
 extern void erts_deliver_time(void);
 extern void erts_time_remaining(SysTimeval *);
 extern int erts_init_time_sup(int, ErtsTimeWarpMode);
diff --git a/erts/emulator/sys/common/erl_os_monotonic_time_extender.c b/erts/emulator/sys/common/erl_os_monotonic_time_extender.c
new file mode 100644
index 0000000000..f3633b7267
--- /dev/null
+++ b/erts/emulator/sys/common/erl_os_monotonic_time_extender.c
@@ -0,0 +1,88 @@
+/*
+ * %CopyrightBegin%
+ * 
+ * Copyright Ericsson AB 2015. All Rights Reserved.
+ * 
+ * The contents of this file are subject to the Erlang Public License,
+ * Version 1.1, (the "License"); you may not use this file except in
+ * compliance with the License. You should have received a copy of the
+ * Erlang Public License along with this software. If not, it can be
+ * retrieved online at http://www.erlang.org/.
+ * 
+ * Software distributed under the License is distributed on an "AS IS"
+ * basis, WITHOUT WARRANTY OF ANY KIND, either express or implied. See
+ * the License for the specific language governing rights and limitations
+ * under the License.
+ * 
+ * %CopyrightEnd%
+ */
+
+#ifdef HAVE_CONFIG_H
+#  include "config.h"
+#endif
+#include "erl_os_monotonic_time_extender.h"
+
+#ifdef USE_THREADS
+
+static void *os_monotonic_time_extender(void *vstatep)
+{
+    ErtsOsMonotonicTimeExtendState *state = (ErtsOsMonotonicTimeExtendState *) vstatep;
+    long sleep_time = state->check_interval*1000;
+    Uint32 (*raw_os_mtime)(void) = state->raw_os_monotonic_time;
+    Uint32 last_msb = 0;
+
+    while (1) {
+	Uint32 msb = (*raw_os_mtime)() & (((Uint32) 1) << 31);
+
+	if (msb != last_msb) {
+	    int ix = ((int) (last_msb >> 31)) & 1;
+	    Uint32 xtnd = (Uint32) erts_atomic32_read_nob(&state->extend[ix]);
+	    erts_atomic32_set_nob(&state->extend[ix], (erts_aint32_t) (xtnd + 1));
+	    last_msb = msb;
+	}
+	erts_milli_sleep(sleep_time);
+    }
+
+    erl_exit(ERTS_ABORT_EXIT, "os_monotonic_time_extender thread terminating");
+    return NULL;
+}
+
+static erts_tid_t os_monotonic_extender_tid;
+#endif
+
+void
+erts_init_os_monotonic_time_extender(ErtsOsMonotonicTimeExtendState *statep,
+				     Uint32 (*raw_os_monotonic_time)(void),
+				     int check_seconds)
+{
+#ifdef USE_THREADS
+    statep->raw_os_monotonic_time = raw_os_monotonic_time;
+    erts_atomic32_init_nob(&statep->extend[0], (erts_aint32_t) 0);
+    erts_atomic32_init_nob(&statep->extend[1], (erts_aint32_t) 0);
+    statep->check_interval = check_seconds;
+
+#else
+    statep->extend[0] = (Uint32) 0;
+    statep->extend[1] = (Uint32) 0;
+    statep->last_msb = (ErtsMonotonicTime) 0;
+#endif
+}
+
+void
+erts_late_init_os_monotonic_time_extender(ErtsOsMonotonicTimeExtendState *statep)
+{
+#ifdef USE_THREADS
+    erts_thr_opts_t thr_opts = ERTS_THR_OPTS_DEFAULT_INITER;
+    thr_opts.detached = 1;
+    thr_opts.suggested_stack_size = 4;
+
+#if 0
+    thr_opts.name = "os_monotonic_time_extender";
+#endif
+
+    erts_thr_create(&os_monotonic_extender_tid,
+		    os_monotonic_time_extender,
+		    (void*) statep,
+		    &thr_opts);
+#endif
+}
diff --git a/erts/emulator/sys/common/erl_os_monotonic_time_extender.h b/erts/emulator/sys/common/erl_os_monotonic_time_extender.h
new file mode 100644
index 0000000000..0f9e7c86ae
--- /dev/null
+++ b/erts/emulator/sys/common/erl_os_monotonic_time_extender.h
@@ -0,0 +1,65 @@
+/*
+ * %CopyrightBegin%
+ * 
+ * Copyright Ericsson AB 2015. All Rights Reserved.
+ * 
+ * The contents of this file are subject to the Erlang Public License,
+ * Version 1.1, (the "License"); you may not use this file except in
+ * compliance with the License. You should have received a copy of the
+ * Erlang Public License along with this software. If not, it can be
+ * retrieved online at http://www.erlang.org/.
+ * 
+ * Software distributed under the License is distributed on an "AS IS"
+ * basis, WITHOUT WARRANTY OF ANY KIND, either express or implied. See
+ * the License for the specific language governing rights and limitations
+ * under the License.
+ * 
+ * %CopyrightEnd%
+ */
+
+#ifndef ERL_OS_MONOTONIC_TIME_EXTENDER_H__
+#define ERL_OS_MONOTONIC_TIME_EXTENDER_H__
+
+#include "sys.h"
+#include "erl_threads.h"
+
+typedef struct {
+#ifdef USE_THREADS
+    Uint32 (*raw_os_monotonic_time)(void);
+    erts_atomic32_t extend[2];
+    int check_interval;
+#else
+    Uint32 extend[2];
+    ErtsMonotonicTime last_msb;
+#endif
+} ErtsOsMonotonicTimeExtendState;
+
+#ifdef USE_THREADS
+#  define ERTS_CHK_EXTEND_OS_MONOTONIC_TIME(S, RT) ((void) 1)
+#  define ERTS_EXTEND_OS_MONOTONIC_TIME(S, RT)				\
+    ((((ErtsMonotonicTime)						\
+       erts_atomic32_read_nob(&((S)->extend[((int) ((RT) >> 31)) & 1]))) \
+      << 32)								\
+     + (RT))
+#else
+#  define ERTS_CHK_EXTEND_OS_MONOTONIC_TIME(S, RT)			\
+    do {								\
+	Uint32 msb__ = (RT) & (((Uint32) 1) << 31);			\
+	if (msb__ != (S)->last_msb) {					\
+	    int ix__ = ((int) ((S)->last_msb >> 31)) & 1;		\
+	    (S)->extend[ix__]++;					\
+	    (S)->last_msb = msb;					\
+	}								\
+    } while (0)
+#  define ERTS_EXTEND_OS_MONOTONIC_TIME(S, RT)				\
+    ((((ErtsMonotonicTime) (S)->extend[((int) ((RT) >> 31)) & 1]) << 32) + (RT))
+#endif
+
+void
+erts_init_os_monotonic_time_extender(ErtsOsMonotonicTimeExtendState *statep,
+				     Uint32 (*raw_os_monotonic_time)(void),
+				     int check_seconds);
+void
+erts_late_init_os_monotonic_time_extender(ErtsOsMonotonicTimeExtendState *statep);
+
+#endif
diff --git a/erts/emulator/sys/unix/erl_unix_sys.h b/erts/emulator/sys/unix/erl_unix_sys.h
index 5417bb2687..303ebeee7c 100644
--- a/erts/emulator/sys/unix/erl_unix_sys.h
+++ b/erts/emulator/sys/unix/erl_unix_sys.h
@@ -206,12 +206,9 @@ ErtsMonotonicTime erts_os_monotonic_time(void);
     || defined(OS_MONOTONIC_TIME_USING_TIMES)
 
 #if defined(OS_MONOTONIC_TIME_USING_TIMES)
+/* Time unit determined at runtime... */
 #  undef ERTS_COMPILE_TIME_MONOTONIC_TIME_UNIT
-#  define ERTS_COMPILE_TIME_MONOTONIC_TIME_UNIT (1000*1000)
-#  define ERTS_HAVE_ERTS_OS_TIME_OFFSET_FINALIZE 1
-void erts_os_time_offset_finalize(void);
-#  define ERTS_HAVE_ERTS_OS_MONOTONIC_TIME_INIT
-void erts_os_monotonic_time_init(void);
+#  define ERTS_COMPILE_TIME_MONOTONIC_TIME_UNIT 0
 #endif
 
 ErtsMonotonicTime erts_os_monotonic_time(void);
diff --git a/erts/emulator/sys/unix/sys_time.c b/erts/emulator/sys/unix/sys_time.c
index 9fdb1930b7..9db727b111 100644
--- a/erts/emulator/sys/unix/sys_time.c
+++ b/erts/emulator/sys/unix/sys_time.c
@@ -33,6 +33,7 @@
 
 #include "sys.h"
 #include "global.h"
+#include "erl_os_monotonic_time_extender.h"
 
 #ifdef NO_SYSCONF
 #  define TICKS_PER_SEC()	HZ
@@ -55,36 +56,19 @@
 
 #undef ERTS_SYS_TIME_INTERNAL_STATE_WRITE_FREQ__
 #undef ERTS_SYS_TIME_INTERNAL_STATE_READ_ONLY__
+#undef ERTS_SYS_TIME_INTERNAL_STATE_READ_MOSTLY__
 
 #if defined(OS_MONOTONIC_TIME_USING_TIMES)
 
-#define ERTS_WRAP_SYS_TIMES 1
-#define ERTS_SYS_TIME_INTERNAL_STATE_WRITE_FREQ__
-#define ERTS_SYS_TIME_INTERNAL_STATE_READ_ONLY__
-
-/*
- * Not sure there is a need to use times() anymore, perhaps drop
- * support for this soon...
- *
- * sys_times() might need to be wrapped and the values shifted (right)
- * a bit to cope with faster ticks, this has to be taken care 
- * of dynamically to start with, a special version that uses
- * the times() return value as a high resolution timer can be made
- * to fully utilize the faster ticks, like on windows, but for now, we'll
- * settle with this silly workaround
- */
-#ifdef ERTS_WRAP_SYS_TIMES
-static clock_t sys_times_wrap(void);
-#define KERNEL_TICKS() (sys_times_wrap() &  \
-			((1UL << ((sizeof(clock_t) * 8) - 1)) - 1)) 
-#define ERTS_KERNEL_TICK_TO_USEC(TCKS) (((TCKS)*(1000*1000)) \
-					/ internal_state.r.o.ticks_per_sec_wrap)
-#else
+static Uint32
+get_tick_count(void)
+{
+    struct tms unused;
+    return (Uint32) times(&unused);
+}
 
-#define KERNEL_TICKS() (sys_times(&internal_state.w.f.dummy_tms) &  \
-			((1UL << ((sizeof(clock_t) * 8) - 1)) - 1)) 
-#define ERTS_KERNEL_TICK_TO_USEC(TCKS) (((TCKS)*(1000*1000))/SYS_CLK_TCK)
-#endif
+#define ERTS_SYS_TIME_INTERNAL_STATE_READ_ONLY__
+#define ERTS_SYS_TIME_INTERNAL_STATE_READ_MOSTLY__
 
 #endif
 
@@ -109,8 +93,15 @@ ErtsMonotonicTime clock_gettime_monotonic_verified(void);
 #ifdef ERTS_SYS_TIME_INTERNAL_STATE_READ_ONLY__
 struct sys_time_internal_state_read_only__ {
 #if defined(OS_MONOTONIC_TIME_USING_TIMES)
-    int ticks_bsr;
-    int ticks_per_sec_wrap;
+    int times_shift;
+#endif
+};
+#endif
+
+#ifdef ERTS_SYS_TIME_INTERNAL_STATE_READ_MOSTLY__
+struct sys_time_internal_state_read_mostly__ {
+#if defined(OS_MONOTONIC_TIME_USING_TIMES)
+    ErtsOsMonotonicTimeExtendState os_mtime_xtnd;
 #endif
 };
 #endif
@@ -121,15 +112,6 @@ struct sys_time_internal_state_write_freq__ {
 #if defined(__linux__) && defined(OS_MONOTONIC_TIME_USING_CLOCK_GETTIME)
     ErtsMonotonicTime last_delivered;
 #endif
-#if defined(OS_MONOTONIC_TIME_USING_TIMES)
-    ErtsMonotonicTime last_tick_count;
-    ErtsMonotonicTime last_tick_wrap_count;
-    ErtsMonotonicTime last_tick_monotonic_time;
-    ErtsMonotonicTime last_timeofday_usec;
-#ifndef ERTS_WRAP_SYS_TIMES 
-    SysTimes dummy_tms;
-#endif
-#endif
 };
 #endif
 
@@ -144,6 +126,14 @@ static struct {
 		     * ASSUMED_CACHE_LINE_SIZE];
     } r;
 #endif
+#ifdef ERTS_SYS_TIME_INTERNAL_STATE_READ_MOSTLY__
+    union {
+	struct sys_time_internal_state_read_mostly__ m;
+	char align__[(((sizeof(struct sys_time_internal_state_read_mostly__) - 1)
+		       / ASSUMED_CACHE_LINE_SIZE) + 1)
+		     * ASSUMED_CACHE_LINE_SIZE];
+    } wr;
+#endif
 #ifdef ERTS_SYS_TIME_INTERNAL_STATE_WRITE_FREQ__
     union {
 	struct sys_time_internal_state_write_freq__ f;
@@ -193,8 +183,6 @@ sys_init_time(ErtsSysInitTimeResult *init_resp)
     init_resp->os_monotonic_info.func = "gethrtime";
 #elif defined(OS_MONOTONIC_TIME_USING_TIMES)
     init_resp->os_monotonic_info.func = "times";
-    init_resp->os_monotonic_info.locked_use = 1;
-    init_resp->os_monotonic_info.resolution = TICKS_PER_SEC();
 #else
 # error Unknown erts_os_monotonic_time() implementation
 #endif
@@ -247,7 +235,9 @@ sys_init_time(ErtsSysInitTimeResult *init_resp)
 
 #endif /* defined(ERTS_HAVE_OS_MONOTONIC_TIME_SUPPORT) */
 
+#ifdef ERTS_COMPILE_TIME_MONOTONIC_TIME_UNIT
     init_resp->os_monotonic_time_unit = ERTS_COMPILE_TIME_MONOTONIC_TIME_UNIT;
+#endif
     init_resp->sys_clock_resolution = SYS_CLOCK_RESOLUTION;
 
     /* 
@@ -258,38 +248,40 @@ sys_init_time(ErtsSysInitTimeResult *init_resp)
 	erl_exit(ERTS_ABORT_EXIT, "Can't get clock ticks/sec\n");
     
 #if defined(OS_MONOTONIC_TIME_USING_TIMES)
+#if ERTS_COMPILE_TIME_MONOTONIC_TIME_UNIT
+#  error Time unit is supposed to be determined at runtime...
+#endif
+    {
+	ErtsMonotonicTime resolution = erts_sys_time_data__.r.o.ticks_per_sec;
+	ErtsMonotonicTime time_unit = resolution;
+	int shift = 0;
 
-    if (erts_sys_time_data__.r.o.ticks_per_sec >= 1000) {
-	/* Workaround for beta linux kernels, need to be done in runtime
-	   to make erlang run on both 2.4 and 2.5 kernels. In the future, 
-	   the kernel ticks might as 
-	   well be used as a high res timer instead, but that's for when the 
-	   majority uses kernels with HZ == 1024 */
-	internal_state.r.o.ticks_bsr = 3;
-    } else {
-	internal_state.r.o.ticks_bsr = 0;
-    }
+	while (time_unit < 1000*1000) {
+	    time_unit <<= 1;
+	    shift++;
+	}
 
-    internal_state.r.o.ticks_per_sec_wrap
-	= (erts_sys_time_data__.r.o.ticks_per_sec
-	   >> internal_state.r.o.ticks_bsr);
+	init_resp->os_monotonic_info.resolution = resolution;
+	init_resp->os_monotonic_time_unit = time_unit;
+	init_resp->os_monotonic_info.extended = 1;
+	internal_state.r.o.times_shift = shift;
 
-    erts_smp_mtx_init(&internal_state.w.f.mtx, "os_monotonic_time");
-    internal_state.w.f.last_tick_count = KERNEL_TICKS();
-    internal_state.w.f.last_tick_wrap_count = 0;    
-    internal_state.w.f.last_tick_monotonic_time
-	= ERTS_KERNEL_TICK_TO_USEC(internal_state.w.f.last_tick_count);
-    {
-	SysTimeval tv;
-	sys_gettimeofday(&tv);
-	internal_state.w.f.last_timeofday_usec = tv.tv_sec*(1000*1000);
-	internal_state.w.f.last_timeofday_usec += tv.tv_usec;
+	erts_init_os_monotonic_time_extender(&internal_state.wr.m.os_mtime_xtnd,
+					     get_tick_count,
+					     (1 << 29) / resolution);
     }
-
 #endif /* defined(OS_MONOTONIC_TIME_USING_TIMES) */
 
 }
 
+void
+erts_late_sys_init_time(void)
+{
+#if defined(OS_MONOTONIC_TIME_USING_TIMES)
+    erts_late_init_os_monotonic_time_extender(&internal_state.wr.m.os_mtime_xtnd);
+#endif
+}
+
 #if defined(OS_MONOTONIC_TIME_USING_CLOCK_GETTIME)
 
 static ERTS_INLINE ErtsMonotonicTime
@@ -379,86 +371,14 @@ ErtsMonotonicTime erts_os_monotonic_time(void)
 
 #elif defined(OS_MONOTONIC_TIME_USING_TIMES)
 
-static clock_t sys_times_wrap(void)
-{
-    SysTimes dummy;
-    clock_t result = (sys_times(&dummy) >> internal_state.r.o.ticks_bsr);
-    return result;
-}
-
-void
-erts_os_time_offset_finalize(void)
-{
-    erts_smp_mtx_lock(&internal_state.w.f.mtx);
-    internal_state.w.f.last_tick_wrap_count = 0;
-    erts_smp_mtx_unlock(&internal_state.w.f.mtx);
-}
-
-#define ERTS_TIME_EXCEED_TICK_LIMIT(SYS_TIME, TCK_TIME)			\
-    (((Uint64) (SYS_TIME)) - (((Uint64) (TCK_TIME))			\
-			      - ERTS_KERNEL_TICK_TO_USEC(1))		\
-     > ERTS_KERNEL_TICK_TO_USEC(2))
-
-/* Returns monotonic time in micro seconds */
 ErtsMonotonicTime
 erts_os_monotonic_time(void)
 {
-    SysTimeval tv;
-    ErtsMonotonicTime res;
-    ErtsMonotonicTime tick_count;
-    ErtsMonotonicTime tick_count_usec;
-    ErtsMonotonicTime tick_monotonic_time;
-    ErtsMonotonicTime timeofday_usec;
-    ErtsMonotonicTime timeofday_diff_usec;
-
-    erts_smp_mtx_lock(&internal_state.w.f.mtx);
-
-    tick_count = (ErtsMonotonicTime) KERNEL_TICKS();
-    sys_gettimeofday(&tv);
-
-    if (internal_state.w.f.last_tick_count > tick_count) {
-	internal_state.w.f.last_tick_wrap_count
-	    += (((ErtsMonotonicTime) 1) << ((sizeof(clock_t) * 8) - 1));
-    }
-    internal_state.w.f.last_tick_count = tick_count;
-    tick_count += internal_state.w.f.last_tick_wrap_count;
-
-    tick_count_usec = ERTS_KERNEL_TICK_TO_USEC(tick_count);
-
-    timeofday_usec = (ErtsMonotonicTime) tv.tv_sec*(1000*1000);
-    timeofday_usec += (ErtsMonotonicTime) tv.tv_usec;
-    timeofday_diff_usec = timeofday_usec;
-    timeofday_diff_usec -= internal_state.w.f.last_timeofday_usec;
-    internal_state.w.f.last_timeofday_usec = timeofday_usec;
-
-    if (timeofday_diff_usec < 0) {
-	/* timeofday jumped backwards use tick count only... */
-	tick_monotonic_time = tick_count_usec;
-    }
-    else {
-	/* Use time diff from of timeofday if not off by too much... */
-	tick_monotonic_time = internal_state.w.f.last_tick_monotonic_time;
-	tick_monotonic_time += timeofday_diff_usec;
-
-	if (ERTS_TIME_EXCEED_TICK_LIMIT(tick_monotonic_time, tick_count_usec)) {
-	    /*
-	     * Value off by more than one tick from tick_count, i.e.
-	     * timofday leaped one way or the other. We use
-	     * tick_count_usec as is instead and unfortunately
-	     * get lousy precision.
-	     */
-	    tick_monotonic_time = tick_count_usec;
-	}
-    }
-
-    if (internal_state.w.f.last_tick_monotonic_time < tick_monotonic_time)
-	internal_state.w.f.last_tick_monotonic_time = tick_monotonic_time;
-
-    res = internal_state.w.f.last_tick_monotonic_time;
-
-    erts_smp_mtx_unlock(&internal_state.w.f.mtx);
-
-    return res;
+    Uint32 ticks = get_tick_count();
+    ERTS_CHK_EXTEND_OS_MONOTONIC_TIME(&internal_state.wr.m.os_mtime_xtnd,
+				      ticks);
+    return ERTS_EXTEND_OS_MONOTONIC_TIME(&internal_state.wr.m.os_mtime_xtnd,
+					 ticks) << internal_state.r.o.times_shift;
 }
 
 #endif  /* !defined(OS_MONOTONIC_TIME_USING_TIMES) */
diff --git a/erts/emulator/sys/win32/sys_time.c b/erts/emulator/sys/win32/sys_time.c
index 3a10125c81..5fa575fa3b 100644
--- a/erts/emulator/sys/win32/sys_time.c
+++ b/erts/emulator/sys/win32/sys_time.c
@@ -25,6 +25,7 @@
 #endif
 #include "sys.h"
 #include "assert.h"
+#include "erl_os_monotonic_time_extender.h"
 
 #define LL_LITERAL(X) ERTS_I64_LITERAL(X)
 
@@ -80,6 +81,10 @@ struct sys_time_internal_state_read_only__ {
     BOOL (WINAPI *pQueryPerformanceCounter)(LARGE_INTEGER *);
 };
 
+struct sys_time_internal_state_read_mostly__ {
+    ErtsOsMonotonicTimeExtendState os_mtime_xtnd;
+};
+
 struct sys_time_internal_state_write_freq__ {
     erts_smp_mtx_t mtime_mtx;
     ULONGLONG wrap;
@@ -94,6 +99,12 @@ __declspec(align(ASSUMED_CACHE_LINE_SIZE)) struct {
 		     * ASSUMED_CACHE_LINE_SIZE];
     } r;
     union {
+	struct sys_time_internal_state_read_mostly__ m;
+	char align__[(((sizeof(struct sys_time_internal_state_read_mostly__) - 1)
+		       / ASSUMED_CACHE_LINE_SIZE) + 1)
+		     * ASSUMED_CACHE_LINE_SIZE];
+    } wr;
+    union {
 	struct sys_time_internal_state_write_freq__ f;
 	char align__[(((sizeof(struct sys_time_internal_state_write_freq__) - 1)
 		       / ASSUMED_CACHE_LINE_SIZE) + 1)
@@ -114,29 +125,27 @@ os_monotonic_time_qpc(void)
     return (ErtsMonotonicTime) pc.QuadPart;
 }
 
+static Uint32
+get_tick_count(void)
+{
+    return (Uint32) GetTickCount();
+}
+
 static ErtsMonotonicTime
 os_monotonic_time_gtc32(void) 
 {
-    ULONGLONG res, ticks;
-
-    erts_smp_mtx_lock(&internal_state.w.f.mtime_mtx);
-
-    ticks = (ULONGLONG) (GetTickCount() & 0x7FFFFFFF);
-    if (ticks < internal_state.w.f.last_tick_count)
-	internal_state.w.f.wrap += (ULONGLONG) LL_LITERAL(1) << 31;
-    internal_state.w.f.last_tick_count = ticks;
-    res = ticks + internal_state.w.f.wrap;
-
-    erts_smp_mtx_unlock(&internal_state.w.f.mtime_mtx);
-
-    return (ErtsMonotonicTime) res*1000;
+    Uint32 ticks = (Uint32) GetTickCount();
+    ERTS_CHK_EXTEND_OS_MONOTONIC_TIME(&internal_state.wr.m.os_mtime_xtnd,
+				      tick_count);
+    return ERTS_EXTEND_OS_MONOTONIC_TIME(&internal_state.wr.m.os_mtime_xtnd,
+					 ticks) << 10;
 }
 
 static ErtsMonotonicTime
 os_monotonic_time_gtc64(void) 
 {
     ULONGLONG ticks = (*internal_state.r.o.pGetTickCount64)();
-    return (ErtsMonotonicTime) ticks*1000;
+    return (ErtsMonotonicTime) ticks << 10;
 }
 
 /*
@@ -163,9 +172,14 @@ sys_init_time(ErtsSysInitTimeResult *init_resp)
 
 	init_resp->os_monotonic_info.func = "GetTickCount";
 	init_resp->os_monotonic_info.locked_use = 1;
-	init_resp->os_monotonic_info.resolution = 1000;
-	time_unit = (ErtsMonotonicTime) 1000*1000;
+	/* 10-16 ms resolution according to MicroSoft documentation */
+	init_resp->os_monotonic_info.resolution = 100; /* 10 ms */
+	time_unit = (ErtsMonotonicTime) (1000 << 10);
 	os_mtime_func = os_monotonic_time_gtc32;
+	init_resp->os_monotonic_info.extended = 1;
+	erts_init_os_monotonic_time_extender(&internal_state.wr.m.os_mtime_xtnd,
+					     get_tick_count,
+					     60*60*24*7); /* Check once a week */
     }
     else {
 	int major, minor, build;
@@ -184,8 +198,9 @@ sys_init_time(ErtsSysInitTimeResult *init_resp)
 
 	    init_resp->os_monotonic_info.func = "GetTickCount64";
 	    init_resp->os_monotonic_info.locked_use = 0;
-	    init_resp->os_monotonic_info.resolution = 1000;
-	    time_unit = (ErtsMonotonicTime) 1000*1000;
+	    /* 10-16 ms resolution according to MicroSoft documentation */
+	    init_resp->os_monotonic_info.resolution = 100; /* 10 ms */
+	    time_unit = (ErtsMonotonicTime) (1000 << 10);
 	    os_mtime_func = os_monotonic_time_gtc64;
 	}
 	else { /* Vista or newer... */
@@ -235,6 +250,13 @@ sys_init_time(ErtsSysInitTimeResult *init_resp)
 
 }
 
+void
+erts_late_sys_init_time(void)
+{
+    if (erts_sys_time_data__.r.o.os_monotonic_time == os_monotonic_time_gtc32)
+	erts_late_init_os_monotonic_time_extender(&internal_state.wr.m.os_mtime_xtnd);
+}
+
 /* Returns a switchtimes for DST as UTC filetimes given data from a 
    TIME_ZONE_INFORMATION, see sys_localtime_r for usage. */ 
 static void