Better support for poor os monotonic sources

5 files changed, 255 insertions, 163 deletions

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