Question

启动和运行性能计数器的最小C＃代码量是多少？

我只想测量代码中两点之间的CPU周期数和/或时间。我已经浏览了网络上的所有华夫饼干，但它似乎比这样一个微不足道的任务所需的代码更多。我只是希望快速测量并运行，并将更多精力放在我正在进行的工作上。

Answer 1

我认为你不需要性能计数器。您需要的时间超过StopWatch的时间吗？这非常准确。

Stopwatch watch = Stopwatch.StartNew();

// Do work

watch.Stop();
// elapsed time is in watch.Elapsed

但是，要回答您实际问过的问题：如果您只想查询现有计数器，实际上非常简单。这是一个完整的例子：

using System;
using System.Diagnostics;
using System.Linq;

static class Test
{
    static void Main()
    {
        var processorCategory = PerformanceCounterCategory.GetCategories()
            .FirstOrDefault(cat => cat.CategoryName == "Processor");
        var countersInCategory = processorCategory.GetCounters("_Total");

        DisplayCounter(countersInCategory.First(cnt => cnt.CounterName == "% Processor Time"));
    }

    private static void DisplayCounter(PerformanceCounter performanceCounter)
    {
        while (!Console.KeyAvailable)
        {
            Console.WriteLine("{0}\t{1} = {2}",
                performanceCounter.CategoryName, performanceCounter.CounterName, performanceCounter.NextValue());
            System.Threading.Thread.Sleep(1000);
        }
    }
}

当然，该过程需要适当的权限才能访问您需要的性能计数器。

Answer 2

我喜欢可以接受任何代码块的东西，并用秒表分析代码包装它来测量执行它所花费的时间：

    using System.Diagnostics;
    using System.Threading;

    public static T Profile<T>(Func<T> codeBlock, string description = "")
    {
        Stopwatch stopWatch = new Stopwatch();
        stopWatch.Start();
        T res = codeBlock();
        stopWatch.Stop();
        TimeSpan ts = stopWatch.Elapsed;
        const double thresholdSec = 2;
        double elapsed = ts.TotalSeconds;
        if(elapsed > thresholdSec)
          System.Diagnostics.Debug.Write(description + " code was too slow! It took " +
             elapsed + " second(s).");
        return res;
    }

然后这样称呼：

    Profile(() => MyObj.MySlowMethod());

或：

    Profile(() => MyObj.MySlowMethod(), "I can explain why");

Answer 3

没有琐碎的方法可以在.NET中启动并运行它。但是，我发现最简单的方法是在Enterprise Library之上构建，它提供了一些用于处理性能计数器的开箱即用功能。例如：the Performance Counter Handler

企业库还为您提供了一些功能，可以更轻松地管理性能计数器的安装。

此外，它让你建立在它之上，所以，你可以创建一个AvergeTimeMeter，它允许你这样做：

private static EnterpriseLibraryPerformanceCounter averageRequestTimeCounter = PerformanceCounterManager.GetEnterpriseLibraryCounter(MadPerformanceCountersListener.AverageRequestTime);
private static EnterpriseLibraryPerformanceCounter averageRequestTimeCounterBase = PerformanceCounterManager.GetEnterpriseLibraryCounter(MadPerformanceCountersListener.AverageRequestTimeBase);

public void DoSomethingWeWantToMonitor()
{
    using (new AverageTimeMeter(averageRequestTimeCounter, averageRequestTimeCounterBase))
    {
        // code here that you want to perf mon
    }
}

这允许您简单地将要监视的代码封装在using块中 - 并专注于您实际想要处理的代码，而不是担心所有性能计数器基础结构。

为此，您将创建一个可重复使用的AverageTimeMeter类，如下所示：

public sealed class AverageTimeMeter : IDisposable
{
    private EnterpriseLibraryPerformanceCounter averageCounter;
    private EnterpriseLibraryPerformanceCounter baseCounter;
    private Stopwatch stopWatch;
    private string instanceName;

    public AverageTimeMeter(EnterpriseLibraryPerformanceCounter averageCounter, EnterpriseLibraryPerformanceCounter baseCounter, string instanceName = null)
    {
        this.stopWatch = new Stopwatch();
        this.averageCounter = averageCounter;
        this.baseCounter = baseCounter;
        this.instanceName = instanceName;
        this.stopWatch.Start();
    }

    public void Dispose()
    {
        this.stopWatch.Stop();
        if (this.baseCounter != null)
        {
            this.baseCounter.Increment();
        }

        if (this.averageCounter != null)
        {
            if (string.IsNullOrEmpty(this.instanceName))
            {
                this.averageCounter.IncrementBy(this.stopWatch.ElapsedTicks);
            }
            else
            {
                this.averageCounter.SetValueFor(this.instanceName, this.averageCounter.Value + this.stopWatch.ElapsedTicks);
            }
        }
    }

}

您必须注册您的性能计数器（显示在EntLib示例中），但这应该是您的开始。

最简单的可能性能计数器示例

3 个答案: