Merge branch 'rickard/monotonic-clock-source/OTP-12895' into maint-18

* rickard/monotonic-clock-source/OTP-12895:
  Prefer monotonic time that stop during suspend

2 files changed, 29 insertions, 9 deletions

diff --git a/HOWTO/INSTALL.md b/HOWTO/INSTALL.md
index 4c89370691..837e6cbd76 100644
--- a/HOWTO/INSTALL.md
+++ b/HOWTO/INSTALL.md
@@ -402,6 +402,10 @@ Some of the available `configure` options are:
 	dependant application.
 *   `--enable-gettimeofday-as-os-system-time` - Force usage of `gettimeofday()` for
     OS system time.
+*   `--enable-prefer-elapsed-monotonic-time-during-suspend` - Prefer an OS monotonic
+    time source with elapsed time during suspend.
+*   `--disable-prefer-elapsed-monotonic-time-during-suspend` - Do not prefer an OS
+    monotonic time source with elapsed time during suspend.
 *   `--enable-dirty-schedulers` - Enable the **experimental** dirty schedulers
     functionality. Note that the dirty schedulers functionality is experimental,
     and **not supported**. This functionality **will** be subject to backward
diff --git a/erts/aclocal.m4 b/erts/aclocal.m4
index dd5d3979a7..0714ce6030 100644
--- a/erts/aclocal.m4
+++ b/erts/aclocal.m4
@@ -726,9 +726,15 @@ esac
 
 AC_DEFUN(ERL_MONOTONIC_CLOCK,
 [
-  default_resolution_clock_gettime_monotonic="CLOCK_HIGHRES CLOCK_BOOTTIME CLOCK_MONOTONIC"
-  low_resolution_clock_gettime_monotonic="CLOCK_MONOTONIC_COARSE CLOCK_MONOTONIC_FAST"
-  high_resolution_clock_gettime_monotonic="CLOCK_MONOTONIC_PRECISE"
+  if test "$3" = "yes"; then
+     default_resolution_clock_gettime_monotonic="CLOCK_HIGHRES CLOCK_BOOTTIME CLOCK_MONOTONIC"
+     low_resolution_clock_gettime_monotonic="CLOCK_MONOTONIC_COARSE CLOCK_MONOTONIC_FAST"
+     high_resolution_clock_gettime_monotonic="CLOCK_MONOTONIC_PRECISE"
+  else
+     default_resolution_clock_gettime_monotonic="CLOCK_HIGHRES CLOCK_UPTIME CLOCK_MONOTONIC"
+     low_resolution_clock_gettime_monotonic="CLOCK_MONOTONIC_COARSE CLOCK_UPTIME_FAST"
+     high_resolution_clock_gettime_monotonic="CLOCK_UPTIME_PRECISE"
+  fi
 
   case "$1" in
     high_resolution)
@@ -1466,7 +1472,7 @@ AC_ARG_WITH(with_sparc_memory_order,
 LM_CHECK_THR_LIB
 ERL_INTERNAL_LIBS
 
-ERL_MONOTONIC_CLOCK(high_resolution)
+ERL_MONOTONIC_CLOCK(high_resolution, undefined, no)
 
 case $erl_monotonic_clock_func in
   clock_gettime)
@@ -2212,6 +2218,16 @@ AC_ARG_WITH(clock-gettime-monotonic-id,
 AS_HELP_STRING([--with-clock-gettime-monotonic-id=CLOCKID],
                [specify clock id to use with clock_gettime() for monotonic time)]))
 
+AC_ARG_ENABLE(prefer-elapsed-monotonic-time-during-suspend,
+	      AS_HELP_STRING([--enable-prefer-elapsed-monotonic-time-during-suspend],
+                             [Prefer an OS monotonic time source with elapsed time during suspend])
+	      AS_HELP_STRING([--disable-prefer-elapsed-monotonic-time-during-suspend],
+                             [Do not prefer an OS monotonic time source with elapsed time during suspend]),
+[ case "$enableval" in
+    yes) prefer_elapsed_monotonic_time_during_suspend=yes ;;
+    *)  prefer_elapsed_monotonic_time_during_suspend=no ;;
+  esac ], prefer_elapsed_monotonic_time_during_suspend=no)
+
 AC_ARG_ENABLE(gettimeofday-as-os-system-time,
 	      AS_HELP_STRING([--enable-gettimeofday-as-os-system-time],
                              [Force usage of gettimeofday() for OS system time]),
@@ -2319,13 +2335,13 @@ esac
 
 case "$with_clock_resolution-$with_clock_gettime_monotonic_id" in
   high-no)
-	ERL_MONOTONIC_CLOCK(high_resolution);;
+	ERL_MONOTONIC_CLOCK(high_resolution, undefined, $prefer_elapsed_monotonic_time_during_suspend);;
   low-no)
-	ERL_MONOTONIC_CLOCK(low_resolution);;
+	ERL_MONOTONIC_CLOCK(low_resolution, undefined, $prefer_elapsed_monotonic_time_during_suspend);;
   default-no)
-	ERL_MONOTONIC_CLOCK(default_resolution);;
+	ERL_MONOTONIC_CLOCK(default_resolution, undefined, $prefer_elapsed_monotonic_time_during_suspend);;
   *)
-	ERL_MONOTONIC_CLOCK(custom_resolution, $with_clock_gettime_monotonic_id);;
+	ERL_MONOTONIC_CLOCK(custom_resolution, $with_clock_gettime_monotonic_id, $prefer_elapsed_monotonic_time_during_suspend);;
 esac
 
 case "$erl_monotonic_clock_func-$erl_monotonic_clock_id-$with_clock_gettime_monotonic_id" in
@@ -2373,7 +2389,7 @@ if test $erl_cv_clock_gettime_monotonic_raw = yes; then
   AC_DEFINE(HAVE_CLOCK_GETTIME_MONOTONIC_RAW, [1], [Define if you have clock_gettime(CLOCK_MONOTONIC_RAW, _)])
 fi
 
-ERL_MONOTONIC_CLOCK(high_resolution)
+ERL_MONOTONIC_CLOCK(high_resolution, undefined, no)
 
 case $$erl_monotonic_clock_low_resolution-$erl_monotonic_clock_func in
   no-mach_clock_get_time)