.NET中的高分辨率计时器

Question

我想对我的代码进行一些基本的分析，但发现C＃中的DateTime.Now只有大约16 ms的分辨率。必须有更好的时间来保存我尚未找到的构造。

Answer 1

以下是对操作进行计时的示例代码：

Dim sw As New Stopwatch()
sw.Start()
//Insert Code To Time
sw.Stop()
Dim ms As Long = sw.ElapsedMilliseconds
Console.WriteLine("Total Seconds Elapsed: " & ms / 1000)

编辑：

整洁的事情是它也可以恢复。

Stopwatch sw = new Stopwatch();
foreach(MyStuff stuff in _listOfMyStuff)
{
    sw.Start();
    stuff.DoCoolCalculation();
    sw.Stop();
}
Console.WriteLine("Total calculation time: {0}", sw.Elapsed);

System.Diagnostics.Stopwatch 课程将如果你的系统有一个高分辨率计数器，请使用它。

Answer 2

System.Diagnostics.StopWatch类非常适合分析。

以下链接指向 Vance Morrison的代码计时器博客如果您不想编写自己的测量函数。

Answer 3

对于最高分辨率的性能计数器，您可以使用底层的win32性能计数器。

添加以下P / Invoke sigs：

[System.Runtime.InteropServices.DllImport("Kernel32.dll")]
public static extern bool QueryPerformanceCounter(out long perfcount);

[System.Runtime.InteropServices.DllImport("Kernel32.dll")]
public static extern bool QueryPerformanceFrequency(out long freq);

并使用以下方式调用它们：

#region Query Performance Counter
/// <summary>
/// Gets the current 'Ticks' on the performance counter
/// </summary>
/// <returns>Long indicating the number of ticks on the performance counter</returns>
public static long QueryPerformanceCounter()
{
    long perfcount;
    QueryPerformanceCounter(out perfcount);
    return perfcount;
}
#endregion

#region Query Performance Frequency
/// <summary>
/// Gets the number of performance counter ticks that occur every second
/// </summary>
/// <returns>The number of performance counter ticks that occur every second</returns>
public static long QueryPerformanceFrequency()
{
    long freq;
    QueryPerformanceFrequency(out freq);
    return freq;
}
#endregion

将它全部转移到一个简单的课程中，你准备好了。示例（假设PerformanceCounters的类名称）：

long startCount = PerformanceCounter.QueryPerformanceCounter();
// DoStuff();
long stopCount = PerformanceCounter.QueryPerformanceCounter();
long elapsedCount = stopCount - startCount;
double elapsedSeconds = (double)elapsedCount / PerformanceCounter.QueryPerformanceFrequency();
MessageBox.Show(String.Format("Took {0} Seconds", Math.Round(elapsedSeconds, 6).ToString()));

Answer 4

您可以在Windows中调用高分辨率性能计数器。函数名是kernel32.dll中的QueryPerformanceCounter。

导入C＃的语法：

[DllImport("Kernel32.dll")]
private static extern bool QueryPerformanceCounter(out long lpPerformanceCount);

Windows调用语法：

BOOL QueryPerformanceCounter(      
    LARGE_INTEGER *lpPerformanceCount
);

QueryPerformanceCounter @ MSDN