Use system_time instead of monotonic_time as timestamp in logger

7 files changed, 18 insertions, 21 deletions

diff --git a/lib/kernel/doc/src/logger.xml b/lib/kernel/doc/src/logger.xml
index 183102f240..cac9c39f2a 100644
--- a/lib/kernel/doc/src/logger.xml
+++ b/lib/kernel/doc/src/logger.xml
@@ -111,7 +111,7 @@ logger:error("error happened because: ~p",[Reason]). %% Without macro
 	<list>
 	  <item><c>pid  => self()</c></item>
 	  <item><c>gl   => group_leader()</c></item>
-	  <item><c>time => erlang:monotonic_time(microsecond)</c></item>
+	  <item><c>time => erlang:system_time(microsecond)</c></item>
 	</list>
 	<p>When a log macro is used, Logger also inserts location
 	  information:</p>
@@ -184,8 +184,8 @@ logger:error("error happened because: ~p",[Reason]). %% Without macro
       <name name="timestamp"/>
       <desc>
 	<p>A timestamp produced
-	  with <seealso marker="erts:erlang#monotonic_time-1">
-	    <c>erlang:monotonic_time(microsecond)</c></seealso>.</p>
+	  with <seealso marker="erts:erlang#system_time-1">
+	    <c>erlang:system_time(microsecond)</c></seealso>.</p>
       </desc>
     </datatype>
   </datatypes>
diff --git a/lib/kernel/src/code_server.erl b/lib/kernel/src/code_server.erl
index bbfa2a995d..1a7677295b 100644
--- a/lib/kernel/src/code_server.erl
+++ b/lib/kernel/src/code_server.erl
@@ -1437,7 +1437,7 @@ error_msg(Format, Args) ->
     logger ! {log,error,Format,Args,
               #{pid=>self(),
                 gl=>group_leader(),
-                time=>erlang:monotonic_time(microsecond),
+                time=>erlang:system_time(microsecond),
                 error_logger=>#{tag=>error}}},
     ok.
 
@@ -1446,7 +1446,7 @@ info_msg(Format, Args) ->
     logger ! {log,info,Format,Args,
               #{pid=>self(),
                 gl=>group_leader(),
-                time=>erlang:monotonic_time(microsecond),
+                time=>erlang:system_time(microsecond),
                 error_logger=>#{tag=>info_msg}}},
     ok.
 
diff --git a/lib/kernel/src/logger.erl b/lib/kernel/src/logger.erl
index a839f97e62..281521ae6e 100644
--- a/lib/kernel/src/logger.erl
+++ b/lib/kernel/src/logger.erl
@@ -833,7 +833,7 @@ proc_meta() ->
 
 default(pid) -> self();
 default(gl) -> group_leader();
-default(time) -> erlang:monotonic_time(microsecond).
+default(time) -> erlang:system_time(microsecond).
 
 %% Remove everything upto and including this module from the stacktrace
 filter_stacktrace(Module,[{Module,_,_,_}|_]) ->
diff --git a/lib/kernel/src/logger_formatter.erl b/lib/kernel/src/logger_formatter.erl
index 602c666cc7..a19e7bbc73 100644
--- a/lib/kernel/src/logger_formatter.erl
+++ b/lib/kernel/src/logger_formatter.erl
@@ -197,16 +197,15 @@ truncate(String,Size) ->
             String
     end.
 
-format_time(Timestamp,#{time_offset:=Offset,time_designator:=Des})
-  when is_integer(Timestamp) ->
-    SysTime = Timestamp + erlang:time_offset(microsecond),
+%% SysTime is the system time in microseconds
+format_time(SysTime,#{time_offset:=Offset,time_designator:=Des})
+  when is_integer(SysTime) ->
     calendar:system_time_to_rfc3339(SysTime,[{unit,microsecond},
                                              {offset,Offset},
                                              {time_designator,Des}]).
 
-%% Assuming this is monotonic time in microseconds
-timestamp_to_datetimemicro(Timestamp,Config) when is_integer(Timestamp) ->
-    SysTime = Timestamp + erlang:time_offset(microsecond),
+%% SysTime is the system time in microseconds
+timestamp_to_datetimemicro(SysTime,Config) when is_integer(SysTime) ->
     Micro = SysTime rem 1000000,
     Sec = SysTime div 1000000,
     UniversalTime =  erlang:posixtime_to_universaltime(Sec),
diff --git a/lib/kernel/src/logger_simple.erl b/lib/kernel/src/logger_simple.erl
index 5272455a2d..c8cdf25887 100644
--- a/lib/kernel/src/logger_simple.erl
+++ b/lib/kernel/src/logger_simple.erl
@@ -70,7 +70,7 @@ log(#{msg:=_,meta:=#{time:=_}}=Log,_Config) ->
                 do_log(
                   #{level=>error,
                     msg=>{report,{error,simple_handler_process_dead}},
-                    meta=>#{time=>erlang:monotonic_time(microsecond)}}),
+                    meta=>#{time=>erlang:system_time(microsecond)}}),
                 do_log(Log);
             _ ->
                 ?MODULE ! {log,Log}
@@ -126,7 +126,7 @@ drop_msg(0) ->
 drop_msg(N) ->
     [#{level=>info,
        msg=>{"Simple handler buffer full, dropped ~w messages",[N]},
-       meta=>#{time=>erlang:monotonic_time(microsecond)}}].
+       meta=>#{time=>erlang:system_time(microsecond)}}].
 
 %%%-----------------------------------------------------------------
 %%% Internal
@@ -141,8 +141,7 @@ do_log(#{msg:=Msg,meta:=#{time:=T}}) ->
     display_date(T),
     display(Msg).
 
-display_date(Timestamp0) when is_integer(Timestamp0) ->
-    Timestamp = Timestamp0 + erlang:time_offset(microsecond),
+display_date(Timestamp) when is_integer(Timestamp) ->
     Micro = Timestamp rem 1000000,
     Sec = Timestamp div 1000000,
     {{Y,Mo,D},{H,Mi,S}} = erlang:universaltime_to_localtime(
diff --git a/lib/kernel/test/logger_SUITE.erl b/lib/kernel/test/logger_SUITE.erl
index e602fa2576..1d3410e356 100644
--- a/lib/kernel/test/logger_SUITE.erl
+++ b/lib/kernel/test/logger_SUITE.erl
@@ -769,14 +769,14 @@ process_metadata(_Config) ->
     undefined = logger:get_process_metadata(),
     {error,badarg} = ?TRY(logger:set_process_metadata(bad)),
     ok = logger:add_handler(h1,?MODULE,#{level=>info,filter_default=>log}),
-    Time = erlang:monotonic_time(microsecond),
+    Time = erlang:system_time(microsecond),
     ProcMeta = #{time=>Time,line=>0,custom=>proc},
     ok = logger:set_process_metadata(ProcMeta),
     S1 = ?str,
     ?LOG_INFO(S1,#{custom=>macro}),
     check_logged(info,S1,#{time=>Time,line=>0,custom=>macro}),
 
-    Time2 = erlang:monotonic_time(microsecond),
+    Time2 = erlang:system_time(microsecond),
     S2 = ?str,
     ?LOG_INFO(S2,#{time=>Time2,line=>1,custom=>macro}),
     check_logged(info,S2,#{time=>Time2,line=>1,custom=>macro}),
diff --git a/lib/kernel/test/logger_formatter_SUITE.erl b/lib/kernel/test/logger_formatter_SUITE.erl
index 9baadfd65a..c171165944 100644
--- a/lib/kernel/test/logger_formatter_SUITE.erl
+++ b/lib/kernel/test/logger_formatter_SUITE.erl
@@ -546,8 +546,7 @@ default_time_format(Timestamp) ->
 default_time_format(Timestamp,Utc) ->
     default_time_format(Timestamp,Utc,$T).
 
-default_time_format(Timestamp0,Utc,Sep) ->
-    Timestamp=Timestamp0+erlang:time_offset(microsecond),
+default_time_format(Timestamp,Utc,Sep) ->
     Offset = if Utc -> "Z";
                 true -> ""
              end,
@@ -569,7 +568,7 @@ my_try(Fun) ->
     try Fun() catch C:R:S -> {C,R,hd(S)} end.
 
 timestamp() ->
-    erlang:monotonic_time(microsecond).
+    erlang:system_time(microsecond).
 
 %% necessary?
 add_time(#{time:=_}=Meta) ->