process_count_by_type.ex

 def processes_by_type() do
    procs = Enum.reduce(:erlang.processes(), %{}, fn(pid, acc) ->
      initial_call = case :erlang.process_info(pid, :initial_call) do
                       {:initial_call, {:proc_lib, :init_p, a}} ->
                         case :erlang.process_info(pid, :dictionary) do
                           {:dictionary, d} ->
                             Keyword.get(d, :"$initial_call")
                           _ ->
                             {:proc_lib, :init_p, a}
                         end
                       {:initial_call, {:erlang, :apply, a}} ->
                         case :erlang.process_info(pid, :current_function) do
                           {:current_function, mfa} -> mfa
                           _ -> {:erlang, :apply, a}
                         end
                       {:initial_call, IC} ->
                         IC
                       other ->
                         other
                     end
      Map.update(acc, initial_call, 1, &(&1 + 1))
    end)
    Enum.sort(
      Enum.into(procs, []),
      fn({_, x}, {_, y}) -> x > y end
    )
  end