using System;
using System.Collections.Generic;
using System.Text;
using System.Diagnostics;

namespace Test
{
    internal sealed class BeforeFieldInit {
        public static Int32 s_x = 123;
    }

    internal sealed class Precise
    {
        public static Int32 s_x;
        static Precise() { s_x = 123; }
    }
    class Program
    {
        static void Main(string[] args)
        {
            const Int32 iterations = 1000 * 1000 * 1000;
            PerfTest1(iterations);
            PerfTest2(iterations);
        }
        private static void PerfTest1(Int32 iterations)
        {
            Stopwatch sw = Stopwatch.StartNew();
            for (Int32 x = 0; x < iterations; x++)
            {
                BeforeFieldInit.s_x = 1;
            }
            Console.WriteLine("PrefTest1:{0} BeforeFieldInit", sw.Elapsed);

            sw = Stopwatch.StartNew();
            for (Int32 x = 0; x < iterations; x++)
            {
                Precise.s_x  = 1;
            }
            Console.WriteLine("PrefTest1:{0} Precise", sw.Elapsed);
        }

        private static void PerfTest2(Int32 iterations)
        {
            Stopwatch sw = Stopwatch.StartNew();
            for (Int32 x = 0; x < iterations; x++)
            {
                BeforeFieldInit.s_x = 1;
            }
            Console.WriteLine("PrefTest2:{0} BeforeFieldInit", sw.Elapsed);

            sw = Stopwatch.StartNew();
            for (Int32 x = 0; x < iterations; x++)
            {
                Precise.s_x = 1;
            }
            Console.WriteLine("PrefTest2:{0} Precise", sw.Elapsed);
        }
    }
}

输出结果是：

PrefTest1 :0.9545553 BeforeFieldInit

PrefTest1 :4.5477302 Precise