Process ejabberd_sm messages using several dispatchers (EJABS-1653)

src/ejabberd_sm.erl

@@ -384,7 +384,7 @@ init([]) ->
 				 ejabberd_sm, disconnect_removed_user, 100)
       end, ?MYHOSTS),
     ejabberd_commands:register_commands(commands()),
-
+    start_dispatchers(),
     {ok, #state{}}.
 
 %%--------------------------------------------------------------------
@@ -415,13 +415,19 @@ handle_cast(_Msg, State) ->
 %%                                       {stop, Reason, State}
 %% Description: Handling all non call/cast messages
 %%--------------------------------------------------------------------
-handle_info({route, From, To, Packet}, State) ->
-    case catch do_route(From, To, Packet) of
-	{'EXIT', Reason} ->
-	    ?ERROR_MSG("~p~nwhen processing: ~p",
-		       [Reason, {From, To, Packet}]);
-	_ ->
-	    ok
+handle_info({route, From, To, Packet} = Msg, State) ->
+    case get_proc_num() of
+        N when N > 1 ->
+            #jid{luser = U, lserver = S} = To,
+            get_proc_by_hash({U, S}) ! Msg;
+        _ ->
+            case catch do_route(From, To, Packet) of
+                {'EXIT', Reason} ->
+                    ?ERROR_MSG("~p~nwhen processing: ~p",
+                               [Reason, {From, To, Packet}]);
+                _ ->
+                    ok
+            end
     end,
     {noreply, State};
 handle_info({register_iq_handler, Host, XMLNS, Module, Function}, State) ->
@@ -453,6 +459,7 @@ terminate(_Reason, _State) ->
     ejabberd_hooks:delete(node_up, ?MODULE, node_up, 100),
     ejabberd_hooks:delete(node_hash_update, ?MODULE, migrate, 100),
     ejabberd_commands:unregister_commands(commands()),
+    stop_dispatchers(),
     ok.
 
 %%--------------------------------------------------------------------
@@ -875,6 +882,55 @@ user_resources(User, Server) ->
     Resources =  get_user_resources(User, Server),
     lists:sort(Resources).
 
+get_proc_num() ->
+    erlang:system_info(logical_processors).
+
+get_proc_by_hash(Term) ->
+    N = erlang:phash2(Term, get_proc_num()) + 1,
+    get_proc(N).
+
+get_proc(N) ->
+    list_to_atom(atom_to_list(?MODULE) ++ "_" ++ integer_to_list(N)).
+
+start_dispatchers() ->
+    case get_proc_num() of
+        N when N > 1 ->
+            lists:foreach(
+              fun(I) ->
+                      Pid = spawn(fun dispatch/0),
+                      erlang:register(get_proc(I), Pid)
+              end, lists:seq(1, N));
+        _ ->
+            ok
+    end.
+
+stop_dispatchers() ->
+    case get_proc_num() of
+        N when N > 1 ->
+            lists:foreach(
+              fun(I) ->
+                      get_proc(I) ! stop
+              end, lists:seq(1, N));
+        _ ->
+            ok
+    end.
+
+dispatch() ->
+    receive
+        {route, From, To, Packet} ->
+            case catch do_route(From, To, Packet) of
+                {'EXIT', Reason} ->
+                    ?ERROR_MSG("~p~nwhen processing: ~p",
+                               [Reason, {From, To, Packet}]);
+                _ ->
+                    ok
+            end,
+            dispatch();
+        stop ->
+            stopped;
+        _ ->
+            dispatch()
+    end.
 
 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 %%% Update Mnesia tables