Merge branch 'bg/opt-receive' into dev

* bg/opt-receive:
  Test that gen_server:call/2,3 are fast even with a huge message queue
  erts: Add tests for the receive optimization
  Update primary bootstrap
  erts: Implement recv_mark/1 and recv_set/1 for real
  compiler tests: Cover the error handling code in beam_receive
  compiler test: Test optimization of receive statements
  Optimize selective receives in the presence of a large message queue
  Introduce the new recv_mark/1 and recv_mark/1 instructions
  Compile tests that communicate with R12 nodes with the r12 option
  Move p_run/2 to test_lib
  gen: Inline wait_resp_mon/2 to help the compiler optimize

OTP-8623 bg/opt-receive

reveive statements that can only read out a newly created reference are now
specially optimized so that it will execute in constant time regardless of
the number of messages in the receive queue for the process. That
optimization will benefit calls to gen_server:call(). (See gen:do_call/4
for an example of a receive statement that will be optimized.)

1 files changed, 21 insertions, 24 deletions

diff --git a/lib/stdlib/src/gen.erl b/lib/stdlib/src/gen.erl
index 5aab547644..43df6f621d 100644
--- a/lib/stdlib/src/gen.erl
+++ b/lib/stdlib/src/gen.erl
@@ -1,19 +1,19 @@
 %%
 %% %CopyrightBegin%
-%% 
-%% Copyright Ericsson AB 1996-2009. All Rights Reserved.
-%% 
+%%
+%% Copyright Ericsson AB 1996-2010. All Rights Reserved.
+%%
 %% The contents of this file are subject to the Erlang Public License,
 %% Version 1.1, (the "License"); you may not use this file except in
 %% compliance with the License. You should have received a copy of the
 %% Erlang Public License along with this software. If not, it can be
 %% retrieved online at http://www.erlang.org/.
-%% 
+%%
 %% Software distributed under the License is distributed on an "AS IS"
 %% basis, WITHOUT WARRANTY OF ANY KIND, either express or implied. See
 %% the License for the specific language governing rights and limitations
 %% under the License.
-%% 
+%%
 %% %CopyrightEnd%
 %%
 -module(gen).
@@ -212,7 +212,22 @@ do_call(Process, Label, Request, Timeout) ->
 
 	    catch erlang:send(Process, {Label, {self(), Mref}, Request},
 		  [noconnect]),
-	    wait_resp_mon(Node, Mref, Timeout)
+	    receive
+		{Mref, Reply} ->
+		    erlang:demonitor(Mref, [flush]),
+		    {ok, Reply};
+		{'DOWN', Mref, _, _, noconnection} ->
+		    exit({nodedown, Node});
+		{'DOWN', Mref, _, _, Reason} ->
+		    exit(Reason)
+	    after Timeout ->
+		    erlang:demonitor(Mref),
+		    receive
+			{'DOWN', Mref, _, _, _} -> true
+		    after 0 -> true
+		    end,
+		    exit(timeout)
+	    end
     catch
 	error:_ ->
 	    %% Node (C/Java?) is not supporting the monitor.
@@ -233,24 +248,6 @@ do_call(Process, Label, Request, Timeout) ->
 	    end
     end.
 
-wait_resp_mon(Node, Mref, Timeout) ->
-    receive
-	{Mref, Reply} ->
-	    erlang:demonitor(Mref, [flush]),
-	    {ok, Reply};
-	{'DOWN', Mref, _, _, noconnection} ->
-	    exit({nodedown, Node});
-	{'DOWN', Mref, _, _, Reason} ->
-	    exit(Reason)
-    after Timeout ->
-	    erlang:demonitor(Mref),
-	    receive
-		{'DOWN', Mref, _, _, _} -> true 
-	    after 0 -> true
-	    end,
-	    exit(timeout)
-    end.
-
 wait_resp(Node, Tag, Timeout) ->
     receive
 	{Tag, Reply} ->