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);
}