c# 计算程序执行时间,计算一段代码执行所用的时间,测试效率

using System;
using System.Threading;
class Class1
{
    [System.Runtime.InteropServices.DllImport("Kernel32.dll")]
    static extern bool QueryPerformanceCounter(ref long count);
    [System.Runtime.InteropServices.DllImport("Kernel32.dll")]
    static extern bool QueryPerformanceFrequency(ref long count);
    [STAThread]
    static void Main(string[] args)
    {
        long count = 0;
        long count1 = 0;
        long freq = 0;
        double result = 0;
        QueryPerformanceFrequency(ref freq);
        QueryPerformanceCounter(ref count);
        //需要测试的模块

        int heisetoufa;
        for (heisetoufa = 1; heisetoufa < 10000; heisetoufa++)
        {
            Console.WriteLine("第" + heisetoufa + "行");
            if (heisetoufa == 5000)
            {
                Thread.Sleep(10000);
            }
        }

        //需要测试的模块

        QueryPerformanceCounter(ref count1);
        count = count1 - count;
        result = (double)(count) / (double)freq;
        Console.WriteLine("耗时: {0} 秒", result);
        Console.ReadLine();
    }
}