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  • 多线程测试

    总结:

    thread能启动非常多的线程同时工作,但threadpool和Task同时并行的线程数有限,约20个左右,但Threadpool设置最大并行数后则不会超过此数。

    另:thread和threadpool的子线程中如果有未处理的异常,则主程序则会出现“*** 已停止工作”这样的错误(程序自动退出),而Task的子线程中出现未处理的异常时不影响主程序,即主程序不会退出。

     public partial class Form1 : Form
        {
            int count = 0;
            int 总次数 = 0;
            Random r = new Random();
            public Form1()
            {
                InitializeComponent();
            }

            private void button1_Click(object sender, EventArgs e)
            {
                //有300多个线程并行
                this.count = 0;
                this.总次数 = 0;
                for (int m = 0; m < 400; m++)
                {
                    System.Threading.Thread t = new System.Threading.Thread(new System.Threading.ThreadStart(this.run));
                    t.Start();
                }
            }

            private void button2_Click(object sender, EventArgs e)
            {
                //有10到40个线程并行
                this.count = 0;
                this.总次数 = 0;
                int a,b; //得到32767和1000
                 System.Threading.ThreadPool.GetMaxThreads(out a,out b);
                for (int m = 0; m < 400; m++)
                {
                    System.Threading.ThreadPool.QueueUserWorkItem(new WaitCallback( this.run),0);
                }
            }

            private void button5_Click(object sender, EventArgs e)
            {
                //有10到40个线程并行
                this.count = 0;
                this.总次数 = 0;
                int a, b; //得到32767和1000
                System.Threading.ThreadPool.GetMaxThreads(out a, out b);
                //设置为最大10后,并行数稳定在10个,设置最大100后,最多并行还是10到40个,这应该和机器有关
                System.Threading.ThreadPool.SetMaxThreads(10, 100);  
                for (int m = 0; m < 400; m++)
                {
                    System.Threading.ThreadPool.QueueUserWorkItem(new WaitCallback(this.run), 0);
                }
            }

            private void button3_Click(object sender, EventArgs e)
            {
                //有10到40多个线程并行,运行效率基本同于QueueUserWorkItem
                this.count = 0;
                this.总次数 = 0;
               
                for (int m = 0; m < 400; m++)
                {
                    System.Threading.Tasks.Task.Factory.StartNew(this.run);
                }
            }

            private void run()
            {
                Interlocked.Increment(ref this.总次数);
                Interlocked.Increment(ref this.count);
                System.Threading.Thread.Sleep(r.Next(10) * 1000);

                System.Threading.Interlocked.Decrement(ref this.count);

                this.异常();
            }

            private void run(object ob)
            {
                Interlocked.Increment(ref this.总次数);
                Interlocked.Increment(ref this.count);
             
                System.Threading.Thread.Sleep(r.Next(10) * 1000);

                System.Threading.Interlocked.Decrement(ref this.count);

                this.异常();
            }

            private void 异常()
            {
                throw new Exception("ddd");

                //try
                //{
                //    throw new Exception("ddd");
                //}
                //catch (Exception ex)
                //{

                //}
            }

            private void button4_Click(object sender, EventArgs e)
            {
                this.textBox1.Text = this.count.ToString() + " / " + this.总次数;
            }

          
        }

    另外,多线程方式使用  System.Threading.Thread 创建线程时非常慢,创建超过200个创建就会非常明显的阻塞,如:

      private void button4_Click(object sender, EventArgs e)
            {
                for (int m = 0; m < 400; m++)
                {
                    System.Threading.Thread t = new System.Threading.Thread(new System.Threading.ThreadStart(this.run));
                    t.Start();
                }
            }  //这个是在主线程中创建多个子线程,但界面会明显失去响应。

    解决方法:使用async函数,在主界面中创建10000路异步子线程也不会卡顿

     private void button1_Click(object sender, EventArgs e)
            {
                for (int m = 0; m < 1000; m++)
                {
                    this.Ping("3");
                }
            }

            async private void Ping(string host)
            {
             
                System.Threading.Interlocked.Increment(ref this.count);
                Random r = new Random();
                await Task.Delay(r.Next( 5000));
                System.Threading.Interlocked.Increment(ref this.count2);
            }

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  • 原文地址:https://www.cnblogs.com/81/p/9916013.html
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