Helpful stuff for figuring out what's going on in there...

user_default.erl

-module(user_default).

-export([proc_count/1, proc_count/0,
         proc_mem/2, proc_mem/1, proc_mem/0,
         matching/2, matching/1]).


proc_info(X, Info) ->
    case proplists:get_value(X, Info) of
        {proc_lib, init_p, _} ->
            proc_lib:translate_initial_call(Info);
        ICall -> ICall
    end.

show_count_dict(D) ->
    lists:foreach(fun({K,V}) -> io:format("~p: ~p~n", [K, V]) end,
                  lists:keysort(2,
                                dict:fold(fun(K, V, L) -> [{K, V}|L] end,
                                          [], D))).

count_procs(NameLabel, SizeFun) ->
    lists:foldl(fun(Pid, D) ->
                        case process_info(Pid) of
                            undefined -> D;
                            Info ->
                                dict:update_counter(proc_info(NameLabel, Info),
                                                    SizeFun(Info), D)
                        end
                end,
                dict:new(),
                processes()).

proc_count(Which) ->
    show_count_dict(count_procs(Which, fun(_) -> 1 end)).

proc_count() -> proc_count(initial_call).

proc_mem(FunField, MemField) ->
    show_count_dict(count_procs(FunField,
                                fun(Info) ->
                                        erlang:system_info(wordsize) *
                                            proplists:get_value(MemField, Info)
                                end)).

proc_mem(FunField) -> proc_mem(FunField, total_heap_size).

proc_mem() -> proc_mem(initial_call).

matching(Which, Pattern) ->
    [P || P <- processes(), Pattern == proc_info(Which, process_info(P))].

matching(Pattern) -> matching(initial_call, Pattern).