Store messages for 'rex' and 'error_logger' off heap

Performance for processes that receive huge amounts of
messages can be increased by storing the incoming messages
outside the heap (that avoids copying the message in a
garbage collection).

Two OTP processes that are known to receive many messages
are 'rex' (used by 'rpc') and 'error_logger'.

2 files changed, 18 insertions, 4 deletions

diff --git a/lib/kernel/src/error_logger.erl b/lib/kernel/src/error_logger.erl
index 3523f680a3..3ee8e2c6e6 100644
--- a/lib/kernel/src/error_logger.erl
+++ b/lib/kernel/src/error_logger.erl
@@ -360,8 +360,12 @@ init(Max) when is_integer(Max) ->
 %% go back.
 init({go_back, _PostState}) ->  
     {ok, {?buffer_size, 0, []}};
-init(_) ->  %% Start and just relay to other
-    {ok, []}.             %% node if node(GLeader) =/= node().
+init(_) ->
+    %% The error logger process may receive a huge amount of
+    %% messages. Make sure that they are stored off heap to
+    %% avoid exessive GCs.
+    process_flag(message_queue_data, off_heap),
+    {ok, []}.
 
 -spec handle_event(term(), state()) -> {'ok', state()}.
 
diff --git a/lib/kernel/src/rpc.erl b/lib/kernel/src/rpc.erl
index 21bff02214..bd6ea26678 100644
--- a/lib/kernel/src/rpc.erl
+++ b/lib/kernel/src/rpc.erl
@@ -67,17 +67,27 @@
 
 %%------------------------------------------------------------------------
 
+
+%% The rex server may receive a huge amount of
+%% messages. Make sure that they are stored off heap to
+%% avoid exessive GCs.
+
+-define(SPAWN_OPTS, [{spawn_opt,[{message_queue_data,off_heap}]}]).
+
 %% Remote execution and broadcasting facility
 
 -spec start() -> {'ok', pid()} | 'ignore' | {'error', term()}.
 
 start() ->
-    gen_server:start({local,?NAME}, ?MODULE, [], []).
+    gen_server:start({local,?NAME}, ?MODULE, [], ?SPAWN_OPTS).
 
 -spec start_link() -> {'ok', pid()} | 'ignore' | {'error', term()}.
 
 start_link() ->
-    gen_server:start_link({local,?NAME}, ?MODULE, [], []).
+    %% The rex server process may receive a huge amount of
+    %% messages. Make sure that they are stored off heap to
+    %% avoid exessive GCs.
+    gen_server:start_link({local,?NAME}, ?MODULE, [], ?SPAWN_OPTS).
 
 -spec stop() -> term().