java中线程切换的开销

思路：

开三个线程A,B,C

线程A不断的调用LockSupport.park()阻塞自己，一旦发现自己被唤醒，调用Thread.interrupted()清除interrupt标记位，同时增加自增计数

线程B不断的调用线程A的interrupt()方法，将线程A从阻塞中唤醒，一旦唤醒成功，则自增计数

线程C定时输出计数

 

代码如下

 1 import java.util.concurrent.atomic.AtomicInteger;
 2 import java.util.concurrent.locks.LockSupport;
 3 
 4 /**
 5  * Created by cc on 2017/2/6.
 6  */
 7 public class Test {
 8     public static void main(String[] args) {
 9         final AtomicInteger count = new AtomicInteger(0);
10         final Thread thread = new Thread(new Runnable() {
11             public void run() {
12                 while (true) {
13                     LockSupport.park();
14                     Thread.interrupted();//clear interrupt flag
15                 }
16             }
17         });
18 
19         for(int i =0;i<1;i++) {
20             new Thread(new Runnable() {
21                 public void run() {
22                     while (true) {
23                         if (!thread.isInterrupted()) {
24                             thread.interrupt();
25                             count.incrementAndGet();
26                         }
27                     }
28                 }
29             }).start();
30         }
31         new Thread(new Runnable() {
32             public void run() {
33                 long last = 0;
34                 while (true) {
35                     try {
36                         Thread.sleep(1000);
37                         System.out.println(String.format("thread park %d times in 1s", count.get() - last));
38                         last = count.get();
39                     } catch (InterruptedException e) {
40                         e.printStackTrace();
41                     }
42                 }
43             }
44         }).start();
45 
46         thread.start();
47     }
48 }

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