任务延迟与线程睡眠分辨率精度 [英] Task Delay vs Thread Sleep Resolution Accuracy

问题描述

我需要在特定时间后执行功能，因此我使用此代码.

i need to execute a function after a specific amount of time, therefore i use this code.

_start = DateTime.Now;
await Task.Delay(_app.Settings.AudioFileStartVarianz.BaseSpan).ContinueWith(x => 
        {
            Console.WriteLine(DateTime.Now - _start);

        });

让我们说我要等待0.04秒.我现在的问题是，它的工作不够精确.调用该函数5次后，得到以下输出:

Lets say i want to wait for exactly 0.04 seconds. My problem now is that it's not working precise enough. I get following output after calling the function 5 times:

• 00:00:00.0414220
• 00:00:00.0536098
• 00:00:00.0507841
• 00:00:00.0467757
• 00:00:00.0425790

如果我使用此代码，它将更好地工作

if i use this code it works way better

        _start = DateTime.Now;
        Thread.Sleep(_app.Settings.AudioFileStartVarianz.BaseSpan);
        Console.WriteLine(DateTime.Now - _start);

• 00:00:00.0405879
• 00:00:00.0404284
• 00:00:00.0402117
• 00:00:00.0404908
• 00:00:00.0409088

但是现在我有一个问题，该功能没有异步运行，这很不好，因为我正在播放音频文件(NAudio).

But now i have the problem, that the function is not running asynchronous, what is bad because i am playing an audio file (NAudio).

有什么想法可以在这里等待异步，这样我的音频文件就不会停止吗?

Any ideas how i can here wait async, so that my audio file is not stopping?

KR曼努埃尔

推荐答案

两个调用 Thread.Sleep &之间的区别 Task.Delay 是指 Thread.Sleep 调用OS方法来休眠线程，而 Task.Delay 创建一个 Timer 以模拟延迟.

The difference between the two calls, Thread.Sleep & Task.Delay, is that Thread.Sleep calls an OS method to sleep the thread and Task.Delay creates a Timer to simulate the delay.

通话有效...

private static extern int WaitOneNative(SafeHandle waitableSafeHandle, uint millisecondsTimeout, bool hasThreadAffinity, bool exitContext);

...和...

promise.Timer = new Timer(state => ((DelayPromise)state).Complete(), promise, millisecondsDelay, Timeout.Infinite);

...分别.

现在Windows中的计时器分辨率非常低-大约有15ms的错误.我认为正是因为如此，您才能获得结果.

Now timers in windows are notoriously low resolution - with a 15ms error or so. I think it's because of this that you're getting your results.

坏消息是，如您所述，休眠线程不是异步的，因此要获得异步，您需要接受计时器解析错误.我认为您没有任何明智的方法可以避免这种情况.

The bad news is that sleeping the thread is not asynchronous, as you stated, so to get asynchrony you need to accept the timer resolution error. I don't think that there is any sane way for you to avoid it.

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