using System;using System.Collections.Generic;using System.Collections.Concurrent;using System.Diagnostics;using System.Linq;using System.Threading;using System.Threading.Tasks;namespace ParallelDemo{    class Program    {        static void Main(string[] args)        {            // First do the sequential version.            Console.WriteLine("Executing sequential loop...");            Stopwatch stopwatch = new Stopwatch();            stopwatch.Start();
            //单线程执行            for (int i = 0; i < 5; i++)            {                TestMethod();            }            stopwatch.Stop();            Console.WriteLine("Sequential loop time in milliseconds: {0}", stopwatch.ElapsedMilliseconds);            // Reset timer and results matrix.             stopwatch.Reset();            Console.WriteLine("Executing parallel loop...");            stopwatch.Start();
            //多线程执行            Parallel.For(0, 5, i => TestMethod());            stopwatch.Stop();            Console.WriteLine("Parallel loop time in milliseconds: {0}", stopwatch.ElapsedMilliseconds);            // Keep the console window open in debug mode.            Console.WriteLine("Press any key to exit.");            Console.ReadKey();        }        static void TestMethod()        {            var tid = Thread.CurrentThread.ManagedThreadId;            Console.WriteLine("Thread {0} start", tid);            Thread.Sleep(1000);            Console.WriteLine("Thread {0} end", tid);        }    }}

Executing sequential loop...Thread 9 startThread 9 endThread 9 startThread 9 endThread 9 startThread 9 endThread 9 startThread 9 endThread 9 startThread 9 endSequential loop time in milliseconds: 5004Executing parallel loop...Thread 9 startThread 10 startThread 11 startThread 12 startThread 13 startThread 9 endThread 10 endThread 11 endThread 12 endThread 13 endParallel loop time in milliseconds: 1024Press any key to exit.