The reftrick: code

gistfile1.erl

-module(reftrick).
-compile(export_all).

%% Luke Gorrie's favourite profiling macro.
-define(TIME(Tag, Expr),
        (fun() ->
           %% NOTE: timer:tc/4 does an annoying 'catch' so we
           %% need to wrap the result in 'ok' to be able to
           %% detect an unhandled exception.
           {__TIME, __RESULT} =
             timer:tc(erlang, apply, [fun() -> {ok, Expr} end, []]),
           io:format("time(~s): ~18.3fms ~999p~n",
                     [?MODULE, __TIME/1000, Tag]),
           case __RESULT of
             {ok, _}         -> element(2, __RESULT);
             {'EXIT', Error} -> exit(Error)
           end
         end)()).

plain() ->
    ?TIME(recv1, recv(10000)),
    spam(10000),
    ?TIME(recv2, recv(10000)).

ref() ->
    ?TIME(recv1, recv_ref(10000)),
    spam(10000),
    ?TIME(recv2, recv_ref(10000)).

spam(0) -> ok;
spam(N) -> self() ! foo, spam(N-1).

recv(0) -> ok;
recv(N) -> self() ! bar,
           receive bar -> ok end,
           recv(N-1).

recv_ref(0) -> ok;
recv_ref(N) -> Ref = make_ref(),
               self() ! {Ref, bar},
               receive {Ref, bar} -> ok end,
               recv_ref(N-1).

%%% eof