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, 41 insertions, 17 deletions

diff --git a/erts/emulator/beam/erl_process.c b/erts/emulator/beam/erl_process.c
index ea63d20dfa..81bc3d2429 100644
--- a/erts/emulator/beam/erl_process.c
+++ b/erts/emulator/beam/erl_process.c
@@ -43,6 +43,7 @@
 #include "erl_async.h"
 #include "dtrace-wrapper.h"
 #include "erl_ptab.h"
+#include "erl_bif_unique.h"
 
 
 #define ERTS_DELAYED_WAKEUP_INFINITY (~(Uint64) 0)
@@ -702,8 +703,8 @@ init_sched_wall_time(ErtsSchedWallTime *swtp)
 static ERTS_INLINE Uint64
 sched_wall_time_ts(void)
 {
-#ifdef HAVE_GETHRTIME
-    return (Uint64) sys_gethrtime();
+#ifdef ERTS_HAVE_OS_MONOTONIC_TIME_SUPPORT
+    return (Uint64) erts_os_monotonic_time();
 #else
     Uint64 res;
     SysTimeval tv;
@@ -2843,7 +2844,6 @@ scheduler_wait(int *fcalls, ErtsSchedulerData *esdp, ErtsRunQueue *rq)
     else
 #endif
     {
-	erts_aint_t dt;
 
 	erts_smp_atomic32_set_relb(&function_calls, 0);
 	*fcalls = 0;
@@ -2868,6 +2868,7 @@ scheduler_wait(int *fcalls, ErtsSchedulerData *esdp, ErtsRunQueue *rq)
 	    goto sys_aux_work;
 
 	while (spincount-- > 0) {
+	    ErtsMonotonicTime current_time;
 
 	sys_poll_aux_work:
 
@@ -2877,8 +2878,9 @@ scheduler_wait(int *fcalls, ErtsSchedulerData *esdp, ErtsRunQueue *rq)
 	    ASSERT(!erts_port_task_have_outstanding_io_tasks());
 	    erl_sys_schedule(1); /* Might give us something to do */
 
-	    dt = erts_do_time_read_and_reset();
-	    if (dt) erts_bump_timer(dt);
+	    current_time = erts_get_monotonic_time();
+	    if (current_time >= erts_next_timeout_time())
+		erts_bump_timers(current_time);
 
 	sys_aux_work:
 #ifndef ERTS_SMP
@@ -2993,8 +2995,11 @@ scheduler_wait(int *fcalls, ErtsSchedulerData *esdp, ErtsRunQueue *rq)
 
 	erl_sys_schedule(0);
 
-	dt = erts_do_time_read_and_reset();
-	if (dt) erts_bump_timer(dt);
+	{
+	    ErtsMonotonicTime current_time = erts_get_monotonic_time();
+	    if (current_time >= erts_next_timeout_time())
+		erts_bump_timers(current_time);
+	}
 
 #ifndef ERTS_SMP
 	if (rq->len == 0 && !rq->misc.start)
@@ -5276,6 +5281,9 @@ init_scheduler_data(ErtsSchedulerData* esdp, int num,
     esdp->run_queue = runq;
     esdp->run_queue->scheduler = esdp;
 
+    esdp->thr_id = (Uint32) num;
+    erts_sched_bif_unique_init(esdp);
+
     if (daww_ptr) {
 	init_aux_work_data(&esdp->aux_work_data, esdp, *daww_ptr);
 #ifdef ERTS_SMP
@@ -7717,6 +7725,8 @@ sched_dirty_cpu_thread_func(void *vesdp)
     callbacks.wait = NULL;
     callbacks.finalize_wait = NULL;
 
+    esdp->thr_id += erts_no_schedulers;
+
     erts_thr_progress_register_unmanaged_thread(&callbacks);
 #ifdef ERTS_ENABLE_LOCK_CHECK
     {
@@ -7778,6 +7788,8 @@ sched_dirty_io_thread_func(void *vesdp)
     callbacks.wait = NULL;
     callbacks.finalize_wait = NULL;
 
+    esdp->thr_id += erts_no_schedulers + erts_no_dirty_cpu_schedulers;
+
     erts_thr_progress_register_unmanaged_thread(&callbacks);
 #ifdef ERTS_ENABLE_LOCK_CHECK
     {
@@ -8897,7 +8909,6 @@ Process *schedule(Process *p, int calls)
 {
     Process *proxy_p = NULL;
     ErtsRunQueue *rq;
-    erts_aint_t dt;
     ErtsSchedulerData *esdp;
     int context_reds;
     int fcalls;
@@ -9027,11 +9038,13 @@ Process *schedule(Process *p, int calls)
 
 	ERTS_SMP_CHK_NO_PROC_LOCKS;
 
-	dt = erts_do_time_read_and_reset();
-	if (dt) {
-	    erts_smp_runq_unlock(rq);
-	    erts_bump_timer(dt);
-	    erts_smp_runq_lock(rq);
+	{
+	    ErtsMonotonicTime current_time = erts_get_monotonic_time();
+	    if (current_time >= erts_next_timeout_time()) {
+		erts_smp_runq_unlock(rq);
+		erts_bump_timers(current_time);
+		erts_smp_runq_lock(rq);
+	    }
 	}
 	BM_STOP_TIMER(system);
 
@@ -9177,6 +9190,7 @@ Process *schedule(Process *p, int calls)
 	else if (!ERTS_SCHEDULER_IS_DIRTY(esdp) &&
 		 (fcalls > input_reductions &&
 		  prepare_for_sys_schedule(esdp, !0))) {
+	    ErtsMonotonicTime current_time;
 	    /*
 	     * Schedule system-level activities.
 	     */
@@ -9189,8 +9203,10 @@ Process *schedule(Process *p, int calls)
 #endif
 	    erts_smp_runq_unlock(rq);
 	    erl_sys_schedule(1);
-	    dt = erts_do_time_read_and_reset();
-	    if (dt) erts_bump_timer(dt);
+
+	    current_time = erts_get_monotonic_time();
+	    if (current_time >= erts_next_timeout_time())
+		erts_bump_timers(current_time);
 
 #ifdef ERTS_SMP
 	    erts_smp_runq_lock(rq);
@@ -11501,7 +11517,8 @@ static void doit_exit_monitor(ErtsMonitor *mon, void *vpcontext)
     ErtsMonitor *rmon;
     Process *rp;
 
-    if (mon->type == MON_ORIGIN) {
+    switch (mon->type) {
+    case MON_ORIGIN:
 	/* We are monitoring someone else, we need to demonitor that one.. */
 	if (is_atom(mon->pid)) { /* remote by name */
 	    ASSERT(is_node_name_atom(mon->pid));
@@ -11564,7 +11581,8 @@ static void doit_exit_monitor(ErtsMonitor *mon, void *vpcontext)
 		}
 	    }
 	}
-    } else { /* type == MON_TARGET */
+	break;
+    case MON_TARGET:
 	ASSERT(mon->type == MON_TARGET);
 	ASSERT(is_pid(mon->pid) || is_internal_port(mon->pid));
 	if (is_internal_port(mon->pid)) {
@@ -11623,6 +11641,12 @@ static void doit_exit_monitor(ErtsMonitor *mon, void *vpcontext)
 		}
 	    }
 	}
+	break;
+    case MON_TIME_OFFSET:
+	erts_demonitor_time_offset(mon->ref);
+	break;
+    default:
+	ERTS_INTERNAL_ERROR("Invalid monitor type");
     }
  done:
     /* As the monitors are previously removed from the process,