How to run a Erlang Process periodically with Precise Time (i.e. 10ms)

Question

I want to run a periodic erlang process every 10ms (based on wall clock time), the 10ms should be as accurate as possible; what should be the right way to implement it?

Answer 1

If you want really reliable and accurate periodic process you should rely on actual wall clock time using erlang:monotonic_time/0,1. If you use method in Stratus3D's answer you will eventually fall behind.

start_link(Period) when Period > 0, is_integer(Period) ->
  gen_server:start_link({local, ?SERVER}, ?MODULE, Period, []).

...

init(Period) ->
    StartT = erlang:monotonic_time(millisecond),
    self() ! tick,
    {ok, {StartT, Period}}.

...

handle_info(tick, {StartT, Period} = S) ->
    Next = Period - (erlang:monotonic_time(millisecond)-StartT) rem Period,
    _Timer = erlang:send_after(Next, self(), tick),
    do_task(),
    {noreply, S}.

You can test in the shell:

spawn(fun() ->
    P = 1000,
    StartT = erlang:monotonic_time(millisecond),
    self() ! tick,
    (fun F() ->
        receive
          tick ->
            Next = P - (erlang:monotonic_time(millisecond)-StartT) rem P,
            erlang:send_after(Next, self(), tick),
            io:format("X~n", []),
            F()
        end
      end)()
  end).