最简单的可能性能计数器示例

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.我只想快速测量并运行,并将更多精力放在我正在进行的工作上.

Answer 1

我不认为你需要一个性能计数器.你需要的时间超过了从StopWatch获得的时间吗？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;
    }

然后这样称呼它:

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

要么:

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