我对dynamicC＃的性能有疑问。我读过dynamic使编译器再次运行，但是它做什么呢？

是否必须使用dynamic变量作为参数重新编译整个方法，还是仅使用具有动态行为/上下文的那些行重新编译整个方法？

我注意到，使用dynamic变量会使简单的for循环速度降低2个数量级。

我玩过的代码：

internal class Sum2
{
    public int intSum;
}

internal class Sum
{
    public dynamic DynSum;
    public int intSum;
}

class Program
{
    private const int ITERATIONS = 1000000;

    static void Main(string[] args)
    {
        var stopwatch = new Stopwatch();
        dynamic param = new Object();
        DynamicSum(stopwatch);
        SumInt(stopwatch);
        SumInt(stopwatch, param);
        Sum(stopwatch);

        DynamicSum(stopwatch);
        SumInt(stopwatch);
        SumInt(stopwatch, param);
        Sum(stopwatch);

        Console.ReadKey();
    }

    private static void Sum(Stopwatch stopwatch)
    {
        var sum = 0;
        stopwatch.Reset();
        stopwatch.Start();
        for (int i = 0; i < ITERATIONS; i++)
        {
            sum += i;
        }
        stopwatch.Stop();

        Console.WriteLine(string.Format("Elapsed {0}", stopwatch.ElapsedMilliseconds));
    }

    private static void SumInt(Stopwatch stopwatch)
    {
        var sum = new Sum();
        stopwatch.Reset();
        stopwatch.Start();
        for (int i = 0; i < ITERATIONS; i++)
        {
            sum.intSum += i;
        }
        stopwatch.Stop();

        Console.WriteLine(string.Format("Class Sum int Elapsed {0}", stopwatch.ElapsedMilliseconds));
    }

    private static void SumInt(Stopwatch stopwatch, dynamic param)
    {
        var sum = new Sum2();
        stopwatch.Reset();
        stopwatch.Start();
        for (int i = 0; i < ITERATIONS; i++)
        {
            sum.intSum += i;
        }
        stopwatch.Stop();

        Console.WriteLine(string.Format("Class Sum int Elapsed {0} {1}", stopwatch.ElapsedMilliseconds, param.GetType()));
    }

    private static void DynamicSum(Stopwatch stopwatch)
    {
        var sum = new Sum();
        stopwatch.Reset();
        stopwatch.Start();
        for (int i = 0; i < ITERATIONS; i++)
        {
            sum.DynSum += i;
        }
        stopwatch.Stop();

        Console.WriteLine(String.Format("Dynamic Sum Elapsed {0}", stopwatch.ElapsedMilliseconds));
    }