Unexpected bad results for delegates in C #

Question

I posted this question earlier about dynamically compiling code in C #, and the answer led to another question.

One suggestion is that I use delegates that I tried and they work well. However, they roll about 8.4 X slower than direct calls, which makes no sense.

What is wrong with this code?

My .Net 4.0 results, 64 bit, run exe directly: 62, 514, 530

public static int Execute(int i) { return i * 2; }

private void button30_Click(object sender, EventArgs e)
{
    CSharpCodeProvider foo = new CSharpCodeProvider();

    var res = foo.CompileAssemblyFromSource(
        new System.CodeDom.Compiler.CompilerParameters()
        {
            GenerateInMemory = true,
            CompilerOptions = @"/optimize",                    
        },
        @"public class FooClass { public static int Execute(int i) { return i * 2; }}"
    );

    var type = res.CompiledAssembly.GetType("FooClass");
    var obj = Activator.CreateInstance(type);
    var method = type.GetMethod("Execute");
    int i = 0, t1 = Environment.TickCount, t2;
    //var input = new object[] { 2 };

    //for (int j = 0; j < 10000000; j++)
    //{
    //    input[0] = j;
    //    var output = method.Invoke(obj, input);
    //    i = (int)output;
    //}

    //t2 = Environment.TickCount;

    //MessageBox.Show((t2 - t1).ToString() + Environment.NewLine + i.ToString());

    t1 = Environment.TickCount;

    for (int j = 0; j < 100000000; j++)
    {
        i = Execute(j);
    }

    t2 = Environment.TickCount;

    MessageBox.Show("Native: " + (t2 - t1).ToString() + Environment.NewLine + i.ToString());

    var func = (Func<int, int>) Delegate.CreateDelegate(typeof (Func<int, int>), method);

    t1 = Environment.TickCount;

    for (int j = 0; j < 100000000; j++)
    {
        i = func(j);
    }

    t2 = Environment.TickCount;

    MessageBox.Show("Dynamic delegate: " + (t2 - t1).ToString() + Environment.NewLine + i.ToString());

    Func<int, int> funcL = Execute;

    t1 = Environment.TickCount;

    for (int j = 0; j < 100000000; j++)
    {
        i = funcL(j);
    }

    t2 = Environment.TickCount;

    MessageBox.Show("Delegate: " + (t2 - t1).ToString() + Environment.NewLine + i.ToString());
}

Answer 1

. . , . (. ), - .

( ) .

Answer 2

, Execute , "" .

, , i * 2 . ( i * 2, , , , .)

Execute , inlining (/ MethodImplOptions.NoInlining); . , :

[MethodImpl(MethodImplOptions.NoInlining)]
static int Execute(int i) { return ((i / 63.53) == 34.23) ? -1 : (i * 2); }
public static volatile int Result;

private static void Main(string[] args)
{
    const int iterations = 100000000;

    {
        Result = Execute(42);  // pre-jit
        var s = Stopwatch.StartNew();

        for (int i = 0; i < iterations; i++)
        {
            Result = Execute(i);
        }
        s.Stop();
        Console.WriteLine("Native: " + s.ElapsedMilliseconds);
    }

    {
        Func<int, int> func;
        using (var cscp = new CSharpCodeProvider())
        {
            var cp = new CompilerParameters { GenerateInMemory = true, CompilerOptions = @"/optimize" };
            string src = @"public static class Foo { public static int Execute(int i) { return ((i / 63.53) == 34.23) ? -1 : (i * 2); } }";

            var cr = cscp.CompileAssemblyFromSource(cp, src);
            var mi = cr.CompiledAssembly.GetType("Foo").GetMethod("Execute");
            func = (Func<int, int>)Delegate.CreateDelegate(typeof(Func<int, int>), mi);
        }

        Result = func(42);  // pre-jit
        var s = Stopwatch.StartNew();

        for (int i = 0; i < iterations; i++)
        {
            Result = func(i);
        }
        s.Stop();
        Console.WriteLine("Dynamic delegate: " + s.ElapsedMilliseconds);
    }

    {
        Func<int, int> func = Execute;
        Result = func(42);  // pre-jit

        var s = Stopwatch.StartNew();
        for (int i = 0; i < iterations; i++)
        {
            Result = func(i);
        }
        s.Stop();
        Console.WriteLine("Delegate: " + s.ElapsedMilliseconds);
    }
}