Interop overhead microbenchmark

Interop

using System;
using System.Security;
using System.Runtime.InteropServices;

class Test
{
    [DllImport("kernel32.dll")]
    [SuppressUnmanagedCodeSecurityAttribute]
    extern static int GetTickCount();

    static void Main() {
        int start = Environment.TickCount;
        for (int i = 0; i < 1000000000; i++)
            GetTickCount();
        int end = Environment.TickCount;
        Console.WriteLine(end-start);
    }
}