c# - 以毫秒变化运行循环

问题描述

这个问题之前以不同的形式被问过好几次，但我还是不太明白。

我需要找到一种方法来准确地（或非常接近地）在毫秒变化时触发 while 循环。

这个想法是第一个 while 循环将等待那段时间 - 毫秒之间的时间，一旦毫秒变化（或非常接近这种变化），开始做任何需要的事情（此时计算它的迭代量可以在 1 毫秒内完成）。

我的问题是，关于 MS 更改和循环时间，我的时间计算是否正确？

如果是这样，为什么输出不一致？或者至少输出接近的数字？（因为理论上，循环应该运行大约相同的时间，因此应该发生大约相同数量的迭代），如果是这样，它输出这些数字的原因可能是因为进程在运行时“失去了 CPU”？

如果需要，我不介意在 c 或 c++ 中执行此操作

这是我当前的代码（使用 c#）：

{
    int incerments_per_ms = 0;
    const long ticks_per_ms = 10000; //10000 ticks per ms 

    var start = DateTime.Now.Ticks;//get current time in ticks since jan 1st 2000 00:00

    while ((DateTime.Now.Ticks - start) <= nano_seconds_in_ms) { }
    start += ticks_per_ms;//raise 1 ms 
    while ((DateTime.Now.Ticks - start) <= nano_seconds_in_ms)
    {
        incerments_per_ms++;
    }

    Console.WriteLine(incerments_per_ms.ToString());

    if (min == 0)
        min = incerments_per_ms;

    if (min > incerments_per_ms)
        min = incerments_per_ms;

    if (max < incerments_per_ms)
        max = incerments_per_ms;

    sum += incerments_per_ms;
}

int avg = sum / iterations;

Console.WriteLine("minimum is: " + min.ToString());
Console.WriteLine("maximum is: " + max.ToString());
Console.WriteLine("average is: " + avg.ToString() + "\n\n\n");

50 次迭代的输出：

标签： c#datetime

解决方案

这是一个完全荒谬的解决方案，由于显而易见的原因，它不会完全准确。

前提是，只需时间一堆SpinWait(10)，然后设置分辨率。显然，还有许多其他方法可以取得不同程度的成功。

当然，您可以扩展以下内容并根据口味进行调整，它能够在大多数情况下（在 C# 中）解决毫秒时间问题，并在我的电脑上漂移0.01 ms：

const int cycles = 10000000;

var s = Stopwatch.StartNew();
for (int i = 0; i < cycles; i++)
   Thread.SpinWait(10);

s.Stop();

var spinRate = cycles / s.ElapsedMilliseconds;

Console.WriteLine($"Time Taken {s.ElapsedMilliseconds}ms");
Console.WriteLine($"spinRate {spinRate}");

var ticks = DateTime.Now.Ticks;

var array = new string[100];

for (var i = 0; i < 100; i++)
{
   for (var j = 0; j < (int)spinRate; j++)
      Thread.SpinWait(10);

   array[i] = $"Ticks at : {((DateTime.Now.Ticks - ticks) / (double)10000)}ms";
}

Console.WriteLine(string.Join(Environment.NewLine, array));

输出

Time Taken 3375ms
spinRate 2962
Ticks at : 1.6557ms
Ticks at : 3.5533ms
Ticks at : 4.5521ms
Ticks at : 5.5597ms
Ticks at : 6.5644ms
Ticks at : 7.5631ms
Ticks at : 8.5544ms
Ticks at : 9.554ms
Ticks at : 10.5443ms
Ticks at : 11.5346ms
Ticks at : 12.5354ms
Ticks at : 13.6026ms
Ticks at : 14.7118ms
Ticks at : 15.7672ms
Ticks at : 16.758ms
Ticks at : 17.7482ms
Ticks at : 18.813ms
Ticks at : 19.8041ms
Ticks at : 20.795ms
Ticks at : 21.7858ms
Ticks at : 22.7817ms
Ticks at : 23.7728ms
Ticks at : 24.7637ms
Ticks at : 25.7543ms
Ticks at : 26.7448ms
Ticks at : 27.7735ms
Ticks at : 28.8142ms
Ticks at : 29.8768ms
Ticks at : 30.868ms
Ticks at : 31.8593ms
Ticks at : 32.9084ms
Ticks at : 33.8998ms
Ticks at : 34.8902ms
Ticks at : 35.9574ms
Ticks at : 36.9484ms
Ticks at : 37.9449ms
Ticks at : 38.936ms
Ticks at : 39.9268ms
Ticks at : 40.9171ms
Ticks at : 41.9079ms
Ticks at : 42.9165ms
Ticks at : 43.9077ms
Ticks at : 44.898ms
Ticks at : 45.8881ms
Ticks at : 46.9491ms
Ticks at : 47.9401ms
Ticks at : 48.9311ms
Ticks at : 49.9219ms
Ticks at : 50.9127ms
Ticks at : 51.9754ms
Ticks at : 53.004ms
Ticks at : 53.9949ms
Ticks at : 54.9851ms
Ticks at : 55.9759ms
Ticks at : 56.9666ms
Ticks at : 57.9568ms
Ticks at : 58.9778ms
Ticks at : 59.9696ms
Ticks at : 60.9644ms
Ticks at : 62.0114ms
Ticks at : 63.0707ms
Ticks at : 64.0622ms
Ticks at : 65.1154ms
Ticks at : 66.1062ms
Ticks at : 67.0963ms
Ticks at : 68.111ms
Ticks at : 69.1789ms
Ticks at : 70.1699ms
Ticks at : 71.1601ms
Ticks at : 72.1502ms
Ticks at : 73.1409ms
Ticks at : 74.1311ms
Ticks at : 75.1287ms
Ticks at : 76.1199ms
Ticks at : 77.1101ms
Ticks at : 78.1003ms
Ticks at : 79.0907ms
Ticks at : 80.1556ms
Ticks at : 81.1466ms
Ticks at : 82.1373ms
Ticks at : 83.1736ms
Ticks at : 84.1645ms
Ticks at : 85.2285ms
Ticks at : 86.2196ms
Ticks at : 87.2104ms
Ticks at : 88.2008ms
Ticks at : 89.1911ms
Ticks at : 90.2238ms
Ticks at : 91.2148ms
Ticks at : 92.2055ms
Ticks at : 93.1964ms
Ticks at : 94.1871ms
Ticks at : 95.1774ms
Ticks at : 96.1681ms
Ticks at : 97.2371ms
Ticks at : 98.308ms
Ticks at : 99.2993ms
Ticks at : 100.2903ms
Ticks at : 101.2808ms
Ticks at : 102.3488ms

c# - 以毫秒变化运行循环

问题描述

解决方案

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