using System;
using System.Runtime.CompilerServices;
using System.Threading.Tasks;
using System.Diagnostics;

namespace ConsoleApplication2
{
    class Program
    {
        static void Main(string[] args)
        {
            var s = new Stopwatch();
            // run some things to ensure everything is jitted
            {
                Console.WriteLine("Priming... ");
                s.Start();
                s.Stop();
                s.Restart();
                s.Stop();
                Test1();
                Test2();
                Console.WriteLine(s.Elapsed);
                Console.WriteLine("Priming complete.");
            }
            // test 1 -- use a local variable
            {
                Console.WriteLine("Local variable test... ");
                s.Restart();
                Test1();
                s.Stop();
                Console.WriteLine(s.Elapsed);
            }
            // test 2 -- use boxing
            {
                Console.WriteLine("Boxing test... ");
                s.Restart();
                Test2();
                s.Stop();
                Console.WriteLine(s.Elapsed);
            }
        }

        [MethodImpl(MethodImplOptions.NoInlining)]
        private static void Test1()
        {
            var tasks = new Task[1000000];
            for (var i = 0; i < 1000000; ++i)
            {
                var j = i;
                tasks[i] = new Task(() => ProcessItem(j));
                tasks[i].Start();
            }
            Task.WaitAll(tasks);
        }

        [MethodImpl(MethodImplOptions.NoInlining)]
        private static void Test2()
        {
            var tasks = new Task[1000000];
            for (var i = 0; i < 1000000; ++i)
            {
                tasks[i] = new Task(o => ProcessItem((int)o), i);
                tasks[i].Start();
            }
            Task.WaitAll(tasks);
        }

        [MethodImpl(MethodImplOptions.NoInlining)]
        private static void ProcessItem(int j)
        {
            ++j;
        }
    }
}