bm_ets_list.erl

-module(bm_ets).

-export([run/0]).
-include_lib("stdlib/include/ms_transform.hrl").


run() ->
  ETS = fill_ets(),
  List = fill_list(),
  io:format("Initialized, starting~n"),
  T1 = erlang:now(),
  run_ets(ETS, 5000, false),
  T2 = erlang:now(),
  run_list(List, 5000, false),
  T3 = erlang:now(),
  run_ets(ETS, 5000, true),
  T4 = erlang:now(),
  run_list(List, 5000, true),
  T5 = erlang:now(),
  io:format("[RO] ETS: ~p, List: ~p~n", [timer:now_diff(T2,T1), timer:now_diff(T3,T2)]),
  io:format("[RW] ETS: ~p, List: ~p~n", [timer:now_diff(T4,T3), timer:now_diff(T5,T4)]),
  ok.
  
  
fill_ets() ->
  ETS = ets:new(bm_ets, [set]),
  [ets:insert(ETS, Entry) || Entry <- fill_list()],
  ETS.

fill_list() ->
  [{Num, random_state(), make_ref()} || Num <- lists:seq(1,5000) ].
  
random_state() ->
  Rand = random:uniform(100),
  if 
    Rand > 67 -> active;
    Rand > 33 -> starting;
    true -> paused
  end.
    
  
  
run_ets(_, 0, _) -> ok;
run_ets(ETS, Num, RW) ->
  State = active,
  MS = ets:fun2ms(fun({Id, S, Pid}) when S == State -> {Id, Pid} end),
  List = ets:select(ETS, MS),
  [Pid || {_Id,Pid} <- List],
  case RW of
    true -> ets:update_element(ETS, random:uniform(5000), {2, random_state()});
    _ -> ok
  end,
  run_ets(ETS, Num-1, RW).

run_list(_, 0, _) -> ok;
run_list(Clients, Num, RW) ->
  State = active,
  [Pid || {_Id, S, Pid} <- Clients, S == State],
  Key = random:uniform(5000),
  Clients1 = case RW of
    true ->
      case lists:keyfind(Key, 1, Clients) of
        false -> Clients;
        Tuple ->
          lists:keystore(Key, 1, Clients, setelement(2, Tuple, random_state()))
      end;
    _ -> Clients
  end,
  run_list(Clients1, Num-1, RW).