如何以精确时间（即10ms）定期运行Erlang过程 [英] How to run a Erlang Process periodically with Precise Time (i.e. 10ms)

问题描述

我想每10ms（基于挂钟时间）运行一个周期性的erlang进程，10ms应尽可能准确;应该采用什么方式实施？

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?

推荐答案

如果你想要真正可靠准确的定期过程，你应该依靠实际的挂钟时间，使用 erlang ：monotonic_time / 0,1 。如果您在 Stratus3D 的答案你最终会落后。

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(),
    {ok, S}.

您可以在shell中测试：

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).

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