Merge branch 'rickard/monotonic-time-improvements/OTP-13222' into maint

* rickard/monotonic-time-improvements/OTP-13222:
  Introduce time management in native APIs
  Introduce time warp safe replacement for safe_fixed option
  Introduce time warp safe trace timestamp formats

11 files changed, 321 insertions, 60 deletions

diff --git a/lib/kernel/doc/src/seq_trace.xml b/lib/kernel/doc/src/seq_trace.xml
index 3439111035..9f191d488d 100644
--- a/lib/kernel/doc/src/seq_trace.xml
+++ b/lib/kernel/doc/src/seq_trace.xml
@@ -127,6 +127,34 @@ seq_trace:set_token(OldToken), % activate the trace token again
               enables/disables a timestamp to be generated for each
               traced event. Default is <c>false</c>.</p>
           </item>
+          <tag><c>set_token(strict_monotonic_timestamp, <anno>Bool</anno>)</c></tag>
+          <item>
+            <p>A trace token flag (<c>true | false</c>) which
+            enables/disables a strict monotonic timestamp to be generated
+	    for each traced event. Default is <c>false</c>. Timestamps will
+	    consist of
+	    <seealso marker="erts:time_correction#Erlang_Monotonic_Time">Erlang
+	    monotonic time</seealso> and a monotonically increasing
+	    integer. The time-stamp has the same format and value
+	    as produced by <c>{erlang:monotonic_time(),
+	    erlang:unique_integer([monotonic])}</c>.</p>
+          </item>
+          <tag><c>set_token(monotonic_timestamp, <anno>Bool</anno>)</c></tag>
+          <item>
+            <p>A trace token flag (<c>true | false</c>) which
+            enables/disables a strict monotonic timestamp to be generated
+	    for each traced event. Default is <c>false</c>. Timestamps
+	    will use
+	    <seealso marker="erts:time_correction#Erlang_Monotonic_Time">Erlang
+	    monotonic time</seealso>. The time-stamp has the same
+	    format and value as produced by <c>erlang:monotonic_time()</c>.</p>
+          </item>
+	  <p>If multiple timestamp flags are passed, <c>timestamp</c> has
+	  precedence over <c>strict_monotonic_timestamp</c> which
+	  in turn has precedence over <c>monotonic_timestamp</c>. All
+	  timestamp flags are remembered, so if two are passed
+	  and the one with highest precedence later is disabled
+	  the other one will become active.</p>
         </taglist>
       </desc>
     </func>
diff --git a/lib/kernel/src/kernel.app.src b/lib/kernel/src/kernel.app.src
index b5555ca1a5..419dc0a2fc 100644
--- a/lib/kernel/src/kernel.app.src
+++ b/lib/kernel/src/kernel.app.src
@@ -116,6 +116,6 @@
   {applications, []},
   {env, [{error_logger, tty}]},
   {mod, {kernel, []}},
-  {runtime_dependencies, ["erts-7.0", "stdlib-2.6", "sasl-2.6"]}
+  {runtime_dependencies, ["erts-7.3", "stdlib-2.6", "sasl-2.6"]}
  ]
 }.
diff --git a/lib/kernel/src/seq_trace.erl b/lib/kernel/src/seq_trace.erl
index 07ccd3e494..a7a782c29c 100644
--- a/lib/kernel/src/seq_trace.erl
+++ b/lib/kernel/src/seq_trace.erl
@@ -23,7 +23,9 @@
 -define(SEQ_TRACE_SEND, 1).       %(1 << 0)
 -define(SEQ_TRACE_RECEIVE, 2).    %(1 << 1)
 -define(SEQ_TRACE_PRINT, 4).      %(1 << 2)
--define(SEQ_TRACE_TIMESTAMP, 8).  %(1 << 3)
+-define(SEQ_TRACE_NOW_TIMESTAMP, 8). %(1 << 3)
+-define(SEQ_TRACE_STRICT_MON_TIMESTAMP, 16). %(1 << 4)
+-define(SEQ_TRACE_MON_TIMESTAMP, 32). %(1 << 5)
 
 -export([set_token/1,
 	 set_token/2,
@@ -37,7 +39,7 @@
 
 %%---------------------------------------------------------------------------
 
--type flag()       :: 'send' | 'receive' | 'print' | 'timestamp'.
+-type flag()       :: 'send' | 'receive' | 'print' | 'timestamp' | 'monotonic_timestamp' | 'strict_monotonic_timestamp'.
 -type component()  :: 'label' | 'serial' | flag().
 -type value()      :: (Integer :: non_neg_integer())
                     | {Previous :: non_neg_integer(),
@@ -135,5 +137,9 @@ decode_flags(Flags) ->
     Print = (Flags band ?SEQ_TRACE_PRINT) > 0,
     Send = (Flags band ?SEQ_TRACE_SEND) > 0,
     Rec = (Flags band ?SEQ_TRACE_RECEIVE) > 0,
-    Ts = (Flags band ?SEQ_TRACE_TIMESTAMP) > 0,
-    [{print,Print},{send,Send},{'receive',Rec},{timestamp,Ts}].
+    NowTs = (Flags band ?SEQ_TRACE_NOW_TIMESTAMP) > 0,
+    StrictMonTs = (Flags band ?SEQ_TRACE_STRICT_MON_TIMESTAMP) > 0,
+    MonTs = (Flags band ?SEQ_TRACE_MON_TIMESTAMP) > 0,
+    [{print,Print},{send,Send},{'receive',Rec},{timestamp,NowTs},
+     {strict_monotonic_timestamp, StrictMonTs},
+     {monotonic_timestamp, MonTs}].
diff --git a/lib/kernel/test/seq_trace_SUITE.erl b/lib/kernel/test/seq_trace_SUITE.erl
index 7df0bc3d2f..6a63f7bc9c 100644
--- a/lib/kernel/test/seq_trace_SUITE.erl
+++ b/lib/kernel/test/seq_trace_SUITE.erl
@@ -35,6 +35,11 @@
 						%-define(line_trace, 1).
 -include_lib("test_server/include/test_server.hrl").
 
+-define(TIMESTAMP_MODES, [no_timestamp,
+			  timestamp,
+			  monotonic_timestamp,
+			  strict_monotonic_timestamp]).
+
 -define(default_timeout, ?t:minutes(1)).
 
 suite() -> [{ct_hooks,[ts_install_cth]}].
@@ -75,6 +80,17 @@ end_per_testcase(_Case, Config) ->
 token_set_get(doc) -> [];
 token_set_get(suite) -> [];
 token_set_get(Config) when is_list(Config) ->
+    do_token_set_get(timestamp),
+    do_token_set_get(monotonic_timestamp),
+    do_token_set_get(strict_monotonic_timestamp).
+    
+do_token_set_get(TsType) ->
+    io:format("Testing ~p~n", [TsType]),
+    Flags = case TsType of
+		timestamp -> 15;
+		strict_monotonic_timestamp -> 23;
+		monotonic_timestamp -> 39
+	    end,
     ?line Self = self(),
     ?line seq_trace:reset_trace(),
     %% Test that initial seq_trace is disabled
@@ -88,22 +104,22 @@ token_set_get(Config) when is_list(Config) ->
     ?line {send,true} = seq_trace:get_token(send),
     ?line false = seq_trace:set_token('receive',true),
     ?line {'receive',true} = seq_trace:get_token('receive'),
-    ?line false = seq_trace:set_token(timestamp,true),
-    ?line {timestamp,true} = seq_trace:get_token(timestamp),
+    ?line false = seq_trace:set_token(TsType,true),
+    ?line {TsType,true} = seq_trace:get_token(TsType),
     %% Check the whole token
-    ?line {15,17,0,Self,0} = seq_trace:get_token(), % all flags are set
+    ?line {Flags,17,0,Self,0} = seq_trace:get_token(), % all flags are set
     %% Test setting and reading the 'serial' field
     ?line {0,0} = seq_trace:set_token(serial,{3,5}),
     ?line {serial,{3,5}} = seq_trace:get_token(serial),
     %% Check the whole token, test that a whole token can be set and get
-    ?line {15,17,5,Self,3} = seq_trace:get_token(),
-    ?line seq_trace:set_token({15,19,7,Self,5}),
-    ?line {15,19,7,Self,5} = seq_trace:get_token(),
+    ?line {Flags,17,5,Self,3} = seq_trace:get_token(),
+    ?line seq_trace:set_token({Flags,19,7,Self,5}),
+    ?line {Flags,19,7,Self,5} = seq_trace:get_token(),
     %% Check that receive timeout does not reset token
     ?line receive after 0 -> ok end,
-    ?line {15,19,7,Self,5} = seq_trace:get_token(),
+    ?line {Flags,19,7,Self,5} = seq_trace:get_token(),
     %% Check that token can be unset
-    ?line {15,19,7,Self,5} = seq_trace:set_token([]),
+    ?line {Flags,19,7,Self,5} = seq_trace:set_token([]),
     ?line [] = seq_trace:get_token(),
     %% Check that Previous serial counter survived unset token
     ?line 0 = seq_trace:set_token(label, 17),
@@ -139,30 +155,42 @@ tracer_set_get(Config) when is_list(Config) ->
 print(doc) -> [];
 print(suite) -> [];
 print(Config) when is_list(Config) ->
+    lists:foreach(fun do_print/1, ?TIMESTAMP_MODES).
+    
+do_print(TsType) ->
     ?line start_tracer(),
-    ?line seq_trace:set_token(print,true),
+    ?line set_token_flags([print, TsType]),
     ?line seq_trace:print(0,print1),
     ?line seq_trace:print(1,print2),
     ?line seq_trace:print(print3),
     ?line seq_trace:reset_trace(),
-    ?line [{0,{print,_,_,[],print1}},
-	   {0,{print,_,_,[],print3}}] = stop_tracer(2).
+    ?line [{0,{print,_,_,[],print1}, Ts0},
+	   {0,{print,_,_,[],print3}, Ts1}] = stop_tracer(2),
+    check_ts(TsType, Ts0),
+    check_ts(TsType, Ts1).
     
 send(doc) -> [];
 send(suite) -> [];
 send(Config) when is_list(Config) ->
+    lists:foreach(fun do_send/1, ?TIMESTAMP_MODES).
+
+do_send(TsType) ->
     ?line seq_trace:reset_trace(),
     ?line start_tracer(),
     ?line Receiver = spawn(?MODULE,one_time_receiver,[]),
-    ?line seq_trace:set_token(send,true),
+    ?line set_token_flags([send, TsType]),
     ?line Receiver ! send,
     ?line Self = self(),
     ?line seq_trace:reset_trace(),
-    ?line [{0,{send,_,Self,Receiver,send}}] = stop_tracer(1).
+    ?line [{0,{send,_,Self,Receiver,send}, Ts}] = stop_tracer(1),
+    check_ts(TsType, Ts).
 
 distributed_send(doc) -> [];
 distributed_send(suite) -> [];
 distributed_send(Config) when is_list(Config) ->
+    lists:foreach(fun do_distributed_send/1, ?TIMESTAMP_MODES).
+
+do_distributed_send(TsType) ->
     ?line {ok,Node} = start_node(seq_trace_other,[]),
     ?line {_,Dir} = code:is_loaded(?MODULE),
     ?line Mdir = filename:dirname(Dir),
@@ -170,30 +198,39 @@ distributed_send(Config) when is_list(Config) ->
     ?line seq_trace:reset_trace(),
     ?line start_tracer(),
     ?line Receiver = spawn(Node,?MODULE,one_time_receiver,[]),
-    ?line seq_trace:set_token(send,true),
+    ?line set_token_flags([send,TsType]),
     ?line Receiver ! send,
     ?line Self = self(),
     ?line seq_trace:reset_trace(),
     ?line stop_node(Node),
-    ?line [{0,{send,_,Self,Receiver,send}}] = stop_tracer(1).
+    ?line [{0,{send,_,Self,Receiver,send}, Ts}] = stop_tracer(1),
+    check_ts(TsType, Ts).
+    
 
 recv(doc) -> [];
 recv(suite) -> [];
 recv(Config) when is_list(Config) ->
+    lists:foreach(fun do_recv/1, ?TIMESTAMP_MODES).
+
+do_recv(TsType) ->
     ?line seq_trace:reset_trace(),
     ?line start_tracer(),
     ?line Receiver = spawn(?MODULE,one_time_receiver,[]),
-    ?line seq_trace:set_token('receive',true),
+    ?line set_token_flags(['receive',TsType]),
     ?line Receiver ! 'receive',
     %% let the other process receive the message:
     ?line receive after 1 -> ok end,
     ?line Self = self(),
     ?line seq_trace:reset_trace(),
-    ?line [{0,{'receive',_,Self,Receiver,'receive'}}] = stop_tracer(1).
+    ?line [{0,{'receive',_,Self,Receiver,'receive'}, Ts}] = stop_tracer(1),
+    check_ts(TsType, Ts).
 
 distributed_recv(doc) -> [];
 distributed_recv(suite) -> [];
 distributed_recv(Config) when is_list(Config) ->
+    lists:foreach(fun do_distributed_recv/1, ?TIMESTAMP_MODES).
+
+do_distributed_recv(TsType) ->
     ?line {ok,Node} = start_node(seq_trace_other,[]),
     ?line {_,Dir} = code:is_loaded(?MODULE),
     ?line Mdir = filename:dirname(Dir),
@@ -201,7 +238,7 @@ distributed_recv(Config) when is_list(Config) ->
     ?line seq_trace:reset_trace(),
     ?line rpc:call(Node,?MODULE,start_tracer,[]),
     ?line Receiver = spawn(Node,?MODULE,one_time_receiver,[]),
-    ?line seq_trace:set_token('receive',true),
+    ?line set_token_flags(['receive',TsType]),
     ?line Receiver ! 'receive',
     %% let the other process receive the message:
     ?line receive after 1 -> ok end,
@@ -210,16 +247,20 @@ distributed_recv(Config) when is_list(Config) ->
     ?line Result = rpc:call(Node,?MODULE,stop_tracer,[1]),
     ?line stop_node(Node),
     ?line ok = io:format("~p~n",[Result]),
-    ?line [{0,{'receive',_,Self,Receiver,'receive'}}] = Result.
+    ?line [{0,{'receive',_,Self,Receiver,'receive'}, Ts}] = Result,
+    check_ts(TsType, Ts).
 
 trace_exit(doc) -> [];
 trace_exit(suite) -> [];
 trace_exit(Config) when is_list(Config) ->
+    lists:foreach(fun do_trace_exit/1, ?TIMESTAMP_MODES).
+
+do_trace_exit(TsType) ->
     ?line seq_trace:reset_trace(),
     ?line start_tracer(),
     ?line Receiver = spawn_link(?MODULE, one_time_receiver, [exit]),
     ?line process_flag(trap_exit, true),
-    ?line seq_trace:set_token(send,true),
+    ?line set_token_flags([send, TsType]),
     ?line Receiver ! {before, exit},
     %% let the other process receive the message:
     ?line receive
@@ -233,13 +274,18 @@ trace_exit(Config) when is_list(Config) ->
     ?line Result = stop_tracer(2),
     ?line seq_trace:reset_trace(),
     ?line ok = io:format("~p~n", [Result]),
-    ?line [{0, {send, {0,1}, Self, Receiver, {before, exit}}}, 
+    ?line [{0, {send, {0,1}, Self, Receiver, {before, exit}}, Ts0}, 
 	   {0, {send, {1,2}, Receiver, Self,
-	       {'EXIT', Receiver, {exit, {before, exit}}}}}] = Result.
+	       {'EXIT', Receiver, {exit, {before, exit}}}}, Ts1}] = Result,
+    check_ts(TsType, Ts0),
+    check_ts(TsType, Ts1).
 
 distributed_exit(doc) -> [];
 distributed_exit(suite) -> [];
 distributed_exit(Config) when is_list(Config) ->
+    lists:foreach(fun do_distributed_exit/1, ?TIMESTAMP_MODES).
+
+do_distributed_exit(TsType) ->
     ?line {ok, Node} = start_node(seq_trace_other, []),
     ?line {_, Dir} = code:is_loaded(?MODULE),
     ?line Mdir = filename:dirname(Dir),
@@ -248,7 +294,7 @@ distributed_exit(Config) when is_list(Config) ->
     ?line rpc:call(Node, ?MODULE, start_tracer,[]),
     ?line Receiver = spawn_link(Node, ?MODULE, one_time_receiver, [exit]),
     ?line process_flag(trap_exit, true),
-    ?line seq_trace:set_token(send, true),
+    ?line set_token_flags([send, TsType]),
     ?line Receiver ! {before, exit},
     %% let the other process receive the message:
     ?line receive
@@ -264,7 +310,8 @@ distributed_exit(Config) when is_list(Config) ->
     ?line stop_node(Node),
     ?line ok = io:format("~p~n", [Result]),
     ?line [{0, {send, {1, 2}, Receiver, Self, 
-		{'EXIT', Receiver, {exit, {before, exit}}}}}] = Result.
+		{'EXIT', Receiver, {exit, {before, exit}}}}, Ts}] = Result,
+    check_ts(TsType, Ts).
 
 call(doc) -> 
     "Tests special forms {is_seq_trace} and {get_seq_token} "
@@ -361,14 +408,22 @@ port(doc) ->
     "Send trace messages to a port.";
 port(suite) -> [];
 port(Config) when is_list(Config) ->
+    lists:foreach(fun (TsType) -> do_port(TsType, Config) end,
+		  ?TIMESTAMP_MODES).
+
+do_port(TsType, Config) ->
+    io:format("Testing ~p~n",[TsType]),
     ?line Port = load_tracer(Config),
     ?line seq_trace:set_system_tracer(Port),
 
-    ?line seq_trace:set_token(print, true),
+    ?line set_token_flags([print, TsType]),
     ?line Small = [small,term],
     ?line seq_trace:print(0, Small),
     ?line case get_port_message(Port) of
-	      {seq_trace,0,{print,_,_,[],Small}} ->
+	      {seq_trace,0,{print,_,_,[],Small}} when TsType == no_timestamp ->
+		  ok;
+	      {seq_trace,0,{print,_,_,[],Small},Ts0} when TsType /= no_timestamp ->
+		  check_ts(TsType, Ts0),
 		  ok;
 	      Other ->
 		  ?line seq_trace:reset_trace(),
@@ -382,7 +437,10 @@ port(Config) when is_list(Config) ->
     ?line seq_trace:print(0, OtherSmall),
     ?line seq_trace:reset_trace(),
     ?line case get_port_message(Port) of
-	      {seq_trace,0,{print,_,_,[],OtherSmall}} ->
+	      {seq_trace,0,{print,_,_,[],OtherSmall}} when TsType == no_timestamp ->
+		  ok;
+	      {seq_trace,0,{print,_,_,[],OtherSmall}, Ts1} when TsType /= no_timestamp ->
+		  check_ts(TsType, Ts1),
 		  ok;
 	      Other1 ->
 		  ?line ?t:fail({unexpected,Other1})
@@ -399,6 +457,8 @@ port(Config) when is_list(Config) ->
 	      Other2 ->
 		  ?line ?t:fail({unexpected,Other2})
 	  end,
+    unlink(Port),
+    exit(Port,kill),
     ok.
 
 get_port_message(Port) ->
@@ -734,7 +794,7 @@ simple_tracer(Data, DN) ->
 	{seq_trace,Label,Info,Ts} ->
 	    simple_tracer([{Label,Info,Ts}|Data], DN+1);
 	{seq_trace,Label,Info} ->
-	    simple_tracer([{Label,Info}|Data], DN+1);
+	    simple_tracer([{Label,Info, no_timestamp}|Data], DN+1);
 	{stop,N,From} when DN >= N ->
 	    From ! {tracerlog,lists:reverse(Data)}
     end.
@@ -759,7 +819,55 @@ start_tracer() ->
     seq_trace:set_system_tracer(Pid),
     Pid.
 
-    
+
+set_token_flags([]) ->
+    ok;
+set_token_flags([no_timestamp|Flags]) ->
+    seq_trace:set_token(timestamp, false),
+    seq_trace:set_token(monotonic_timestamp, false),
+    seq_trace:set_token(strict_monotonic_timestamp, false),
+    set_token_flags(Flags);
+set_token_flags([Flag|Flags]) ->
+    seq_trace:set_token(Flag, true),
+    set_token_flags(Flags).
+
+check_ts(no_timestamp, Ts) ->
+    try
+	no_timestamp = Ts
+    catch
+	_ : _ ->
+	    ?t:fail({unexpected_timestamp, Ts})
+    end,
+    ok;
+check_ts(timestamp, Ts) ->
+    try
+	{Ms,S,Us} = Ts,
+	true = is_integer(Ms),
+	true = is_integer(S),
+	true = is_integer(Us)
+    catch
+	_ : _ ->
+	    ?t:fail({unexpected_timestamp, Ts})
+    end,
+    ok;
+check_ts(monotonic_timestamp, Ts) ->
+    try
+	true = is_integer(Ts)
+    catch
+	_ : _ ->
+	    ?t:fail({unexpected_timestamp, Ts})
+    end,
+    ok;
+check_ts(strict_monotonic_timestamp, Ts) ->
+    try
+	{MT, UMI} = Ts,
+	true = is_integer(MT),
+	true = is_integer(UMI)
+    catch
+	_ : _ ->
+	    ?t:fail({unexpected_timestamp, Ts})
+    end,
+    ok.
 	
 start_node(Name, Param) ->
     test_server:start_node(Name, slave, [{args, Param}]).
diff --git a/lib/stdlib/doc/src/dets.xml b/lib/stdlib/doc/src/dets.xml
index a0d3f95b6a..48400733d1 100644
--- a/lib/stdlib/doc/src/dets.xml
+++ b/lib/stdlib/doc/src/dets.xml
@@ -399,15 +399,40 @@
               kept in RAM.</p>
           </item>
           <item>
-            <p><c>{safe_fixed,</c> SafeFixed<c>}</c>. If the table
-              is fixed, SafeFixed is a tuple <c>{FixedAtTime, [{Pid,RefCount}]}</c>. <c>FixedAtTime</c> is the time when
+            <p><c>{safe_fixed_monotonic_time, SafeFixed}</c>. If the table
+              is fixed, <c>SafeFixed</c> is a tuple <c>{FixedAtTime, [{Pid,RefCount}]}</c>.
+	      <c>FixedAtTime</c> is the time when
               the table was first fixed, and <c>Pid</c> is the pid of
               the process that fixes the table <c>RefCount</c> times.
               There may be any number of processes in the list. If the
               table is not fixed, SafeFixed is the atom <c>false</c>.</p>
+	      <p><c>FixedAtTime</c> will correspond to the result
+	      returned by
+	      <seealso marker="erts:erlang#monotonic_time/0">erlang:monotonic_time/0</seealso>
+	      at the time of fixation. The usage of <c>safe_fixed_monotonic_time</c> is
+	      <seealso marker="erts:time_correction#Time_Warp_Safe_Code">time warp
+	      safe</seealso>.</p>
           </item>
           <item>
-            <p><c>{version, integer()</c>, the version of the format of
+            <p>
+	      <c>{safe_fixed, SafeFixed}</c>. The same as
+	      <c>{safe_fixed_monotonic_time, SafeFixed}</c> with the exception
+	      of the format and value of <c>FixedAtTime</c>.
+	    </p>
+	    <p>
+	      <c>FixedAtTime</c> will correspond to the result returned by
+	      <seealso marker="erts:erlang#timestamp/0">erlang:timestamp/0</seealso>
+	      at the time of fixation. Note that when the system is using
+	      single or multi
+	      <seealso marker="erts:time_correction#Time_Warp_Modes">time warp
+	      modes</seealso> this might produce strange results. This
+	      since the usage of <c>safe_fixed</c> is not
+	      <seealso marker="erts:time_correction#Time_Warp_Safe_Code">time warp
+	      safe</seealso>. Time warp safe code need to use
+	      <c>safe_fixed_monotonic_time</c> instead.</p>
+          </item>
+          <item>
+            <p><c>{version, integer()}</c>, the version of the format of
               the table.</p>
           </item>
         </list>
diff --git a/lib/stdlib/doc/src/ets.xml b/lib/stdlib/doc/src/ets.xml
index 7b01109ff8..447fe51130 100644
--- a/lib/stdlib/doc/src/ets.xml
+++ b/lib/stdlib/doc/src/ets.xml
@@ -488,14 +488,39 @@ Error: fun containing local Erlang function calls
           <item><c>Item=fixed, Value=boolean()</c>          <br></br>
 
            Indicates if the table is fixed by any process or not.</item>
-          <item>
-            <p><c>Item=safe_fixed, Value={FirstFixed,Info}|false</c>              <br></br>
+          <item><marker id="info_2_safe_fixed_monotonic_time"/>
+            <p><c>Item=safe_fixed|safe_fixed_monotonic_time, Value={FixationTime,Info}|false</c>              <br></br>
 </p>
-            <p>If the table has been fixed using <c>safe_fixtable/2</c>,
-              the call returns a tuple where <c>FirstFixed</c> is the
+            <p>If the table has been fixed using
+	    <seealso marker="#safe_fixtable/2"><c>safe_fixtable/2</c></seealso>,
+              the call returns a tuple where <c>FixationTime</c> is the
               time when the table was first fixed by a process, which
               may or may not be one of the processes it is fixed by
               right now.</p>
+	    <p>The format and value of <c>FixationTime</c> depends on
+	    <c>Item</c>:</p>
+	    <taglist>
+	      <tag><c>safe_fixed</c></tag>
+	      <item><p><c>FixationTime</c> will correspond to the result
+	      returned by
+	      <seealso marker="erts:erlang#timestamp/0">erlang:timestamp/0</seealso>
+	      at the time of fixation. Note that when the system is using
+	      single or multi
+	      <seealso marker="erts:time_correction#Time_Warp_Modes">time warp
+	      modes</seealso> this might produce strange results. This
+	      since the usage of <c>safe_fixed</c> is not
+	      <seealso marker="erts:time_correction#Time_Warp_Safe_Code">time warp
+	      safe</seealso>. Time warp safe code need to use
+	      <c>safe_fixed_monotonic_time</c> instead.</p></item>
+
+	      <tag><c>safe_fixed_monotonic_time</c></tag>
+	      <item><p><c>FixationTime</c> will correspond to the result
+	      returned by
+	      <seealso marker="erts:erlang#monotonic_time/0">erlang:monotonic_time/0</seealso>
+	      at the time of fixation. The usage of <c>safe_fixed_monotonic_time</c> is
+	      <seealso marker="erts:time_correction#Time_Warp_Safe_Code">time warp
+	      safe</seealso>.</p></item>
+	    </taglist>
             <p><c>Info</c> is a possibly empty lists of tuples
               <c>{Pid,RefCount}</c>, one tuple for every process the
               table is fixed by right now. <c>RefCount</c> is the value
@@ -1135,9 +1160,11 @@ clean_all_with_value(Tab,X,Key) ->
           table but never releases it, the memory used by the deleted
           objects will never be freed. The performance of operations on
           the table will also degrade significantly.</p>
-        <p>Use <c>info/2</c> to retrieve information about which
-          processes have fixed which tables. A system with a lot of
-          processes fixing tables may need a monitor which sends alarms
+        <p>Use
+	<seealso marker="#info_2_safe_fixed_monotonic_time"><c>info(Tab,
+	safe_fixed_monotonic_time)</c></seealso> to retrieve information
+	about which processes have fixed which tables. A system with a lot
+	of processes fixing tables may need a monitor which sends alarms
           when tables have been fixed for too long.</p>
         <p>Note that for tables of the <c>ordered_set</c> type,
           <c>safe_fixtable/2</c> is not necessary as calls to
diff --git a/lib/stdlib/src/dets.erl b/lib/stdlib/src/dets.erl
index 6d07f4018a..2d037ff795 100644
--- a/lib/stdlib/src/dets.erl
+++ b/lib/stdlib/src/dets.erl
@@ -372,7 +372,7 @@ info(Tab) ->
       Item :: 'access' | 'auto_save' | 'bchunk_format'
             | 'hash' | 'file_size' | 'filename' | 'keypos' | 'memory'
             | 'no_keys' | 'no_objects' | 'no_slots' | 'owner' | 'ram_file'
-            | 'safe_fixed' | 'size' | 'type' | 'version',
+            | 'safe_fixed' | 'safe_fixed_monotonic_time' | 'size' | 'type' | 'version',
       Value :: term().
 
 info(Tab, owner) ->
@@ -1964,7 +1964,9 @@ do_safe_fixtable(Head, Pid, true) ->
     case Head#head.fixed of 
 	false -> 
 	    link(Pid),
-	    Fixed = {utime_now(), [{Pid, 1}]},
+	    MonTime = erlang:monotonic_time(),
+	    TimeOffset = erlang:time_offset(),
+	    Fixed = {{MonTime, TimeOffset}, [{Pid, 1}]},
 	    Ftab = dets_utils:get_freelists(Head),
 	    Head#head{fixed = Fixed, freelists = {Ftab, Ftab}};
 	{TimeStamp, Counters} ->
@@ -2091,7 +2093,22 @@ finfo(H, no_keys) ->
 finfo(H, no_slots) -> {H, (H#head.mod):no_slots(H)};
 finfo(H, pid) -> {H, self()};
 finfo(H, ram_file) -> {H, H#head.ram_file};
-finfo(H, safe_fixed) -> {H, H#head.fixed};
+finfo(H, safe_fixed) ->
+    {H,
+     case H#head.fixed of
+	 false ->
+	     false;
+	 {{FixMonTime, TimeOffset}, RefList} ->
+	     {make_timestamp(FixMonTime, TimeOffset), RefList}
+     end};
+finfo(H, safe_fixed_monotonic_time) ->
+    {H,
+     case H#head.fixed of
+	 false ->
+	     false;
+	 {{FixMonTime, _TimeOffset}, RefList} ->
+	     {FixMonTime, RefList}
+     end};
 finfo(H, size) -> 
     case catch write_cache(H) of
 	{H2, []} ->
@@ -3275,11 +3292,14 @@ err(Error) ->
 time_now() ->
     erlang:monotonic_time(1000000).
 
--compile({inline, [utime_now/0]}).
-utime_now() ->
-    Time = time_now(),
-    UniqueCounter = erlang:unique_integer([monotonic]),
-    {Time, UniqueCounter}.
+make_timestamp(MonTime, TimeOffset) ->
+    ErlangSystemTime = erlang:convert_time_unit(MonTime+TimeOffset,
+						native,
+						micro_seconds),
+    MegaSecs = ErlangSystemTime div 1000000000000,
+    Secs = ErlangSystemTime div 1000000 - MegaSecs*1000000,
+    MicroSecs = ErlangSystemTime rem 1000000,
+    {MegaSecs, Secs, MicroSecs}.
 
 %%%%%%%%%%%%%%%%%  DEBUG functions %%%%%%%%%%%%%%%%
 
diff --git a/lib/stdlib/src/ets.erl b/lib/stdlib/src/ets.erl
index 847def2fd8..1fca3624dc 100644
--- a/lib/stdlib/src/ets.erl
+++ b/lib/stdlib/src/ets.erl
@@ -146,7 +146,7 @@ info(_) ->
       Tab :: tab(),
       Item :: compressed | fixed | heir | keypos | memory
             | name | named_table | node | owner | protection
-            | safe_fixed | size | stats | type
+            | safe_fixed | safe_fixed_monotonic_time | size | stats | type
 	    | write_concurrency | read_concurrency,
       Value :: term().
 
diff --git a/lib/stdlib/src/stdlib.app.src b/lib/stdlib/src/stdlib.app.src
index 7f9bbbf649..b8a7973cf2 100644
--- a/lib/stdlib/src/stdlib.app.src
+++ b/lib/stdlib/src/stdlib.app.src
@@ -105,7 +105,7 @@
                dets]},
   {applications, [kernel]},
   {env, []},
-  {runtime_dependencies, ["sasl-2.6","kernel-4.1","erts-7.0","crypto-3.3",
+  {runtime_dependencies, ["sasl-2.6","kernel-4.1","erts-7.3","crypto-3.3",
 			  "compiler-5.0"]}
 ]}.
 
diff --git a/lib/stdlib/test/dets_SUITE.erl b/lib/stdlib/test/dets_SUITE.erl
index 7f5e06524a..35e587afcc 100644
--- a/lib/stdlib/test/dets_SUITE.erl
+++ b/lib/stdlib/test/dets_SUITE.erl
@@ -1876,9 +1876,33 @@ fixtable(Config, Version) when is_list(Config) ->
     {ok, _} = dets:open_file(T, [{type, duplicate_bag} | Args]),
     %% In a fixed table, delete and re-insert an object.
     ok = dets:insert(T, {1, a, b}),
+    SysBefore = erlang:timestamp(),
+    MonBefore = erlang:monotonic_time(),
     dets:safe_fixtable(T, true),
+    MonAfter = erlang:monotonic_time(),
+    SysAfter = erlang:timestamp(),
+    Self = self(),
+    {FixMonTime,[{Self,1}]} = dets:info(T,safe_fixed_monotonic_time),
+    {FixSysTime,[{Self,1}]} = dets:info(T,safe_fixed),
+    true = is_integer(FixMonTime),
+    true = MonBefore =< FixMonTime,
+    true = FixMonTime =< MonAfter,
+    {FstMs,FstS,FstUs} = FixSysTime,
+    true = is_integer(FstMs),
+    true = is_integer(FstS),
+    true = is_integer(FstUs),
+    case erlang:system_info(time_warp_mode) of
+	no_time_warp ->
+	    true = timer:now_diff(FixSysTime, SysBefore) >= 0,
+	    true = timer:now_diff(SysAfter, FixSysTime) >= 0;
+	_ ->
+	    %% ets:info(Tab,safe_fixed) not timewarp safe...
+	    ignore
+    end,
     ok = dets:match_delete(T, {1, a, b}),
     ok = dets:insert(T, {1, a, b}),
+    {FixMonTime,[{Self,1}]} = dets:info(T,safe_fixed_monotonic_time),
+    {FixSysTime,[{Self,1}]} = dets:info(T,safe_fixed),
     dets:safe_fixtable(T, false),
     1 = length(dets:match_object(T, '_')),
 
diff --git a/lib/stdlib/test/ets_SUITE.erl b/lib/stdlib/test/ets_SUITE.erl
index ae431d66d9..30a158d9e1 100644
--- a/lib/stdlib/test/ets_SUITE.erl
+++ b/lib/stdlib/test/ets_SUITE.erl
@@ -3989,15 +3989,37 @@ safe_fixtable_do(Opts) ->
     ?line true = ets:safe_fixtable(Tab, true),
     ?line receive after 1 -> ok end,
     ?line true = ets:safe_fixtable(Tab, false),
-    ?line false = ets:info(Tab,safe_fixed),
-    ?line true = ets:safe_fixtable(Tab, true),
+    false = ets:info(Tab,safe_fixed_monotonic_time),
+    false = ets:info(Tab,safe_fixed),
+    SysBefore = erlang:timestamp(),
+    MonBefore = erlang:monotonic_time(),
+    true = ets:safe_fixtable(Tab, true),
+    MonAfter = erlang:monotonic_time(),
+    SysAfter = erlang:timestamp(),
     Self = self(),
-    ?line {{_,_,_},[{Self,1}]} = ets:info(Tab,safe_fixed),
+    {FixMonTime,[{Self,1}]} = ets:info(Tab,safe_fixed_monotonic_time),
+    {FixSysTime,[{Self,1}]} = ets:info(Tab,safe_fixed),
+    true = is_integer(FixMonTime),
+    true = MonBefore =< FixMonTime,
+    true = FixMonTime =< MonAfter,
+    {FstMs,FstS,FstUs} = FixSysTime,
+    true = is_integer(FstMs),
+    true = is_integer(FstS),
+    true = is_integer(FstUs),
+    case erlang:system_info(time_warp_mode) of
+	no_time_warp ->
+	    true = timer:now_diff(FixSysTime, SysBefore) >= 0,
+	    true = timer:now_diff(SysAfter, FixSysTime) >= 0;
+	_ ->
+	    %% ets:info(Tab,safe_fixed) not timewarp safe...
+	    ignore
+    end,
     %% Test that an unjustified 'unfix' is a no-op.
     {Pid,MRef} = my_spawn_monitor(fun() -> true = ets:safe_fixtable(Tab,false) end),
     {'DOWN', MRef, process, Pid, normal} = receive M -> M end,
-    ?line true = ets:info(Tab,fixed),
-    ?line {{_,_,_},[{Self,1}]} = ets:info(Tab,safe_fixed),
+    true = ets:info(Tab,fixed),
+    {FixMonTime,[{Self,1}]} = ets:info(Tab,safe_fixed_monotonic_time),
+    {FixSysTime,[{Self,1}]} = ets:info(Tab,safe_fixed),
     %% badarg's
     ?line {'EXIT', {badarg, _}} = (catch ets:safe_fixtable(Tab, foobar)),
     ?line true = ets:info(Tab,fixed),
@@ -4043,6 +4065,7 @@ info_do(Opts) ->
     ?line undefined = ets:info(non_existing_table_xxyy,type),
     ?line undefined = ets:info(non_existing_table_xxyy,node),
     ?line undefined = ets:info(non_existing_table_xxyy,named_table),
+    ?line undefined = ets:info(non_existing_table_xxyy,safe_fixed_monotonic_time),
     ?line undefined = ets:info(non_existing_table_xxyy,safe_fixed),
     ?line verify_etsmem(EtsMem).
 
@@ -5532,7 +5555,7 @@ otp_8166_zombie_creator(T,Deleted) ->
 						  [{'=<','$1', Deleted}],
 						  [true]}]),
 	    Pid ! zombies_created,
-	    repeat_while(fun() -> case ets:info(T,safe_fixed) of
+	    repeat_while(fun() -> case ets:info(T,safe_fixed_monotonic_time) of
 				      {_,[_P1,_P2]} ->
 					  false;
 				      _ ->