e25.erl

-module (e25).
-compile (export_all).

ringBenchmark(NumberOfNodes, Message, NumberOfLaps) ->
  statistics(runtime),
  statistics(wall_clock),

  FirstNode = spawn(?MODULE, loop, [[]]),
  LastNode = createNode(1, NumberOfNodes, FirstNode),
  FirstNode ! LastNode,

  sendMessage(Message, FirstNode, NumberOfNodes * NumberOfLaps),

  {_, Time1} = statistics(runtime),
  {_, Time2} = statistics(wall_clock),
  io:format("Sent ~p messages in time=~p (~p) milliseconds~n", [NumberOfLaps * NumberOfNodes, Time1, Time2]).

loop(NextNode) ->
  io:format("Spawned with NextNode ~p~n", [NextNode]),

  receive
    {_From, Message, NumberOfHops} ->
      io:format("Message '~p' with NumberOfHops ~p~n", [Message, NumberOfHops]),
      sendMessage(Message, NextNode, NumberOfHops - 1),
      loop(NextNode);
    NewNext when NextNode =:= [] ->
      loop(NewNext)
  end.

createNode(NumberOfNodes, NumberOfNodes, NextNode) -> NextNode;
createNode(NodeNumber, NumberOfNodes, NextNode) ->
  createNode(NodeNumber + 1, NumberOfNodes, spawn(?MODULE, loop, [NextNode])).

sendMessage(_Message, _ToNode, 0) -> void;
sendMessage(Message, ToNode, NumberOfHops) ->
  ToNode ! {self(), Message, NumberOfHops}.