Introduce a new time API

The old time API is based on erlang:now/0. The major issue with
erlang:now/0 is that it was intended to be used for so many
unrelated things. This tied these unrelated operations together
and unnecessarily caused performance, scalability as well as
accuracy, and precision issues for operations that do not need
to have such issues. The new API spreads different functionality
over multiple functions in order to improve on this.

The new API consists of a number of new BIFs:
- erlang:convert_time_unit/3
- erlang:monotonic_time/0
- erlang:monotonic_time/1
- erlang:system_time/0
- erlang:system_time/1
- erlang:time_offset/0
- erlang:time_offset/1
- erlang:timestamp/0
- erlang:unique_integer/0
- erlang:unique_integer/1
- os:system_time/0
- os:system_time/1

and a number of extensions of existing BIFs:
- erlang:monitor(time_offset, clock_service)
- erlang:system_flag(time_offset, finalize)
- erlang:system_info(os_monotonic_time_source)
- erlang:system_info(time_offset)
- erlang:system_info(time_warp_mode)
- erlang:system_info(time_correction)
- erlang:system_info(start_time)

See the "Time and Time Correction in Erlang" chapter of the
ERTS User's Guide for more information.

1 files changed, 45 insertions, 15 deletions

diff --git a/erts/emulator/sys/win32/erl_poll.c b/erts/emulator/sys/win32/erl_poll.c
index 972170d465..5a62b00a68 100644
--- a/erts/emulator/sys/win32/erl_poll.c
+++ b/erts/emulator/sys/win32/erl_poll.c
@@ -285,7 +285,7 @@ struct ErtsPollSet_ {
 #ifdef ERTS_SMP
     erts_smp_mtx_t mtx;
 #endif
-    erts_smp_atomic32_t timeout;
+    erts_atomic64_t timeout_time;
 };
 
 #ifdef ERTS_SMP
@@ -363,6 +363,26 @@ do { \
     wait_standby(PS); \
  } while(0)
 
+static ERTS_INLINE void
+init_timeout_time(ErtsPollSet ps)
+{
+    erts_atomic64_init_nob(&ps->timeout_time,
+			   (erts_aint64_t) ERTS_MONOTONIC_TIME_MAX);
+}
+
+static ERTS_INLINE void
+set_timeout_time(ErtsPollSet ps, ErtsMonotonicTime time)
+{
+    erts_atomic64_set_relb(&ps->timeout_time,
+			   (erts_aint64_t) time);
+}
+
+static ERTS_INLINE ErtsMonotonicTime
+get_timeout_time(ErtsPollSet ps)
+{
+    return (ErtsMonotonicTime) erts_atomic64_read_acqb(&ps->timeout_time);
+}
+
 #define ERTS_POLL_NOT_WOKEN		((erts_aint32_t) 0)
 #define ERTS_POLL_WOKEN_IO_READY	((erts_aint32_t) 1)
 #define ERTS_POLL_WOKEN_INTR		((erts_aint32_t) 2)
@@ -422,15 +442,29 @@ wakeup_cause(ErtsPollSet ps)
 }
 
 static ERTS_INLINE DWORD
-poll_wait_timeout(ErtsPollSet ps, SysTimeval *tvp)
+poll_wait_timeout(ErtsPollSet ps, ErtsMonotonicTime timeout_time)
 {
-    time_t timeout = tvp->tv_sec * 1000 + tvp->tv_usec / 1000;
+    ErtsMonotonicTime current_time, diff_time, timeout;
 
-    if (timeout <= 0) {
+    if (timeout_time == ERTS_POLL_NO_TIMEOUT) {
+    no_timeout:
+	set_timeout_time(ps, ERTS_MONOTONIC_TIME_MIN);
 	woke_up(ps);
 	return (DWORD) 0;
     }
 
+    current_time = erts_get_monotonic_time();
+    diff_time = timeout_time - current_time;
+    if (diff_time <= 0)
+	goto no_timeout;
+
+    /* Round up to nearest milli second */
+    timeout = (ERTS_MONOTONIC_TO_MSEC(diff_time - 1) + 1);
+    if (timeout > INT_MAX)
+	timeout = INT_MAX; /* Also prevents DWORD overflow */
+
+    set_timeout_time(ps, current_time + ERTS_MSEC_TO_MONOTONIC(timeout));
+
     ResetEvent(ps->event_io_ready);
     /*
      * Since we don't know the internals of ResetEvent() we issue
@@ -442,10 +476,6 @@ poll_wait_timeout(ErtsPollSet ps, SysTimeval *tvp)
     if (erts_atomic32_read_nob(&ps->wakeup_state) != ERTS_POLL_NOT_WOKEN)
 	return (DWORD) 0;
 
-    if (timeout > ((time_t) ERTS_AINT32_T_MAX))
-	timeout = ERTS_AINT32_T_MAX; /* Also prevents DWORD overflow */
-
-    erts_smp_atomic32_set_relb(&ps->timeout, (erts_aint32_t) timeout);
     return (DWORD) timeout;
 }
 
@@ -1012,12 +1042,12 @@ void  erts_poll_interrupt(ErtsPollSet ps, int set /* bool */)
 
 void erts_poll_interrupt_timed(ErtsPollSet ps,
 			       int set /* bool */,
-			       erts_short_time_t msec)
+			       ErtsMonotonicTime timeout_time)
 {
-    HARDTRACEF(("In erts_poll_interrupt_timed(%d,%ld)",set,msec));
+    HARDTRACEF(("In erts_poll_interrupt_timed(%d,%ld)",set,timeout_time));
     if (!set)
 	reset_interrupt(ps);
-    else if (erts_smp_atomic32_read_acqb(&ps->timeout) > (erts_aint32_t) msec)
+    else if (get_timeout_time(ps) > timeout_time)
 	set_interrupt(ps);
     HARDTRACEF(("Out erts_poll_interrupt_timed"));
 }
@@ -1092,7 +1122,7 @@ void erts_poll_controlv(ErtsPollSet ps,
 int erts_poll_wait(ErtsPollSet ps,
 		   ErtsPollResFd pr[],
 		   int *len,
-		   SysTimeval *tvp)
+		   ErtsMonotonicTime timeout_time)
 {
     int no_fds;
     DWORD timeout;
@@ -1149,7 +1179,7 @@ int erts_poll_wait(ErtsPollSet ps,
 	no_fds = ERTS_POLL_MAX_RES;
 #endif
 
-    timeout = poll_wait_timeout(ps, tvp);
+    timeout = poll_wait_timeout(ps, timeout_time);
 
     /*HARDDEBUGF(("timeout = %ld",(long) timeout));*/
 
@@ -1242,7 +1272,7 @@ int erts_poll_wait(ErtsPollSet ps,
 	erts_mtx_unlock(&w->mtx);
     }
  done:
-    erts_smp_atomic32_set_nob(&ps->timeout, ERTS_AINT32_T_MAX);
+    set_timeout_time(ps, ERTS_MONOTONIC_TIME_MAX);
     *len = num;
     ERTS_POLLSET_UNLOCK(ps);
     HARDTRACEF(("Out erts_poll_wait"));
@@ -1326,7 +1356,7 @@ ErtsPollSet erts_poll_create_pollset(void)
 #ifdef ERTS_SMP
     erts_smp_mtx_init(&ps->mtx, "pollset");
 #endif
-    erts_smp_atomic32_init_nob(&ps->timeout, ERTS_AINT32_T_MAX);
+    init_timeout_time(ps);
 
     HARDTRACEF(("Out erts_poll_create_pollset"));
     return ps;