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, 105 insertions, 3 deletions

diff --git a/erts/emulator/beam/erl_bif_info.c b/erts/emulator/beam/erl_bif_info.c
index b90362d82c..80d49c7ce2 100644
--- a/erts/emulator/beam/erl_bif_info.c
+++ b/erts/emulator/beam/erl_bif_info.c
@@ -42,6 +42,7 @@
 #include "erl_cpu_topology.h"
 #include "erl_async.h"
 #include "erl_thr_progress.h"
+#include "erl_bif_unique.h"
 #define ERTS_PTAB_WANT_DEBUG_FUNCS__
 #include "erl_ptab.h"
 #ifdef HIPE
@@ -2099,6 +2100,46 @@ BIF_RETTYPE system_info_1(BIF_ALIST_1)
 	BIF_RET(am_opt);
 #endif
 	BIF_RET(res);
+    } else if (BIF_ARG_1 == am_time_offset) {
+	switch (erts_time_offset_state()) {
+	case ERTS_TIME_OFFSET_PRELIMINARY: {
+	    ERTS_DECL_AM(preliminary);
+	    BIF_RET(AM_preliminary);
+	}
+	case ERTS_TIME_OFFSET_FINAL: {
+	    ERTS_DECL_AM(final);
+	    BIF_RET(AM_final);
+	}
+	case ERTS_TIME_OFFSET_VOLATILE: {
+	    ERTS_DECL_AM(volatile);
+	    BIF_RET(AM_volatile);
+	}
+	default:
+	    ERTS_INTERNAL_ERROR("Invalid time offset state");
+	}
+    } else if (ERTS_IS_ATOM_STR("os_monotonic_time_source", BIF_ARG_1)) {
+	BIF_RET(erts_monotonic_time_source(BIF_P));
+    } else if (ERTS_IS_ATOM_STR("time_correction", BIF_ARG_1)) {
+	BIF_RET(erts_has_time_correction() ? am_true : am_false);
+    } else if (ERTS_IS_ATOM_STR("start_time", BIF_ARG_1)) {
+	BIF_RET(erts_get_monotonic_start_time(BIF_P));
+    } else if (ERTS_IS_ATOM_STR("time_warp_mode", BIF_ARG_1)) {
+	switch (erts_time_warp_mode()) {
+	case ERTS_NO_TIME_WARP_MODE: {
+	    ERTS_DECL_AM(no_time_warp);
+	    BIF_RET(AM_no_time_warp);
+	}
+	case ERTS_SINGLE_TIME_WARP_MODE: {
+	    ERTS_DECL_AM(single_time_warp);
+	    BIF_RET(AM_single_time_warp);
+	}
+	case ERTS_MULTI_TIME_WARP_MODE: {
+	    ERTS_DECL_AM(multi_time_warp);
+	    BIF_RET(AM_multi_time_warp);
+	}
+	default:
+	    ERTS_INTERNAL_ERROR("Invalid time warp mode");
+	}
     } else if (BIF_ARG_1 == am_allocated_areas) {
 	res = erts_allocated_areas(NULL, NULL, BIF_P);
 	BIF_RET(res);
@@ -2700,9 +2741,11 @@ BIF_RETTYPE system_info_1(BIF_ALIST_1)
         BIF_RET(make_small(erts_db_get_max_tabs()));
     }
     else if (ERTS_IS_ATOM_STR("tolerant_timeofday",BIF_ARG_1)) {
-	BIF_RET(erts_disable_tolerant_timeofday
-		? am_disabled
-		: am_enabled);
+	if (erts_has_time_correction()
+	    && erts_time_offset_state() == ERTS_TIME_OFFSET_FINAL) {
+	    BIF_RET(am_enabled);
+	}
+	BIF_RET(am_disabled);
     }
     else if (ERTS_IS_ATOM_STR("eager_check_io",BIF_ARG_1)) {
 	BIF_RET(erts_eager_check_io ? am_true : am_false);
@@ -3400,6 +3443,29 @@ BIF_RETTYPE erts_debug_get_internal_state_1(BIF_ALIST_1)
         else if (ERTS_IS_ATOM_STR("mmap", BIF_ARG_1)) {
             BIF_RET(erts_mmap_debug_info(BIF_P));
         }
+	else if (ERTS_IS_ATOM_STR("unique_monotonic_integer_state", BIF_ARG_1)) {
+	    BIF_RET(erts_debug_get_unique_monotonic_integer_state(BIF_P));
+	}
+	else if (ERTS_IS_ATOM_STR("min_unique_monotonic_integer", BIF_ARG_1)) {
+	    Sint64 value = erts_get_min_unique_monotonic_integer();
+	    if (IS_SSMALL(value))
+		BIF_RET(make_small(value));
+	    else {
+		Uint hsz = ERTS_SINT64_HEAP_SIZE(value);
+		Eterm *hp = HAlloc(BIF_P, hsz);
+		BIF_RET(erts_sint64_to_big(value, &hp));
+	    }
+	}
+	else if (ERTS_IS_ATOM_STR("min_unique_integer", BIF_ARG_1)) {
+	    Sint64 value = erts_get_min_unique_integer();
+	    if (IS_SSMALL(value))
+		BIF_RET(make_small(value));
+	    else {
+		Uint hsz = ERTS_SINT64_HEAP_SIZE(value);
+		Eterm *hp = HAlloc(BIF_P, hsz);
+		BIF_RET(erts_sint64_to_big(value, &hp));
+	    }
+	}
     }
     else if (is_tuple(BIF_ARG_1)) {
 	Eterm* tp = tuple_val(BIF_ARG_1);
@@ -3596,6 +3662,38 @@ BIF_RETTYPE erts_debug_get_internal_state_1(BIF_ALIST_1)
 	    }
 	    break;
 	}
+	case 3: {
+	    if (ERTS_IS_ATOM_STR("check_time_config", tp[1])) {
+		int res, time_correction;
+		ErtsTimeWarpMode time_warp_mode;
+		if (tp[2] == am_true)
+		    time_correction = !0;
+		else if (tp[2] == am_false)
+		    time_correction = 0;
+		else
+		    break;
+		if (ERTS_IS_ATOM_STR("no_time_warp", tp[3]))
+		    time_warp_mode = ERTS_NO_TIME_WARP_MODE;
+		else if (ERTS_IS_ATOM_STR("single_time_warp", tp[3]))
+		    time_warp_mode = ERTS_SINGLE_TIME_WARP_MODE;
+		else if (ERTS_IS_ATOM_STR("multi_time_warp", tp[3]))
+		    time_warp_mode = ERTS_MULTI_TIME_WARP_MODE;
+		else
+		    break;
+		res = erts_check_time_adj_support(time_correction,
+						  time_warp_mode);
+		BIF_RET(res ? am_true : am_false);
+	    }
+	    else if (ERTS_IS_ATOM_STR("make_unique_integer", tp[1])) {
+	      Eterm res = erts_debug_make_unique_integer(BIF_P,
+							 tp[2],
+							 tp[3]);
+	      if (is_non_value(res))
+		  break;
+	      BIF_RET(res);
+	    }
+	    break;
+	}
 	default:
 	    break;
 	}
@@ -3897,6 +3995,10 @@ BIF_RETTYPE erts_debug_set_internal_state_2(BIF_ALIST_2)
 		}
 	    }
 	}
+	else if (ERTS_IS_ATOM_STR("unique_monotonic_integer_state", BIF_ARG_1)) {
+	    int res = erts_debug_set_unique_monotonic_integer_state(BIF_ARG_2);
+	    BIF_RET(res ? am_true : am_false);
+	}
     }
 
     BIF_ERROR(BIF_P, BADARG);