• 使用无锁的方式和有锁的方式的程序性能对比


    这里分别使用有锁和无锁两种方式,对一个数值进行增加,一直增加到100000,然后输出使用时间的长短。

      1 import java.util.concurrent.ExecutorService;
      2 import java.util.concurrent.Executors;
      3 import java.util.concurrent.TimeUnit;
      4 import java.util.concurrent.atomic.AtomicInteger;
      5 
      6 public class TestAtomic {
      7 
      8     // 设置线程数量
      9     private static int N = 1000;
     10     // 设置最大值
     11     private static int M = 1000000;
     12 
     13     /**
     14      * 无锁方法
     15      * 
     16      * @throws InterruptedException
     17      */
     18     private static void atomicMethod() throws InterruptedException {
     19         AtomicRun atomicRun = new AtomicRun();
     20         AtomicRun.endValue = M;
     21 
     22         ExecutorService service = Executors.newFixedThreadPool(N);
     23         // 开始时间
     24         long starttime = System.currentTimeMillis();
     25         for (int i = 0; i < N; i++) {
     26             service.submit(atomicRun);
     27         }
     28         service.shutdown();
     29         service.awaitTermination(Integer.MAX_VALUE, TimeUnit.MILLISECONDS);
     30         // 结束时间
     31         long endTime = System.currentTimeMillis();
     32         System.out.println("无锁线程数量为 : " + N + " 开始时间为 : " + starttime
     33                 + " 结束时间为 : " + endTime + " 耗费时间为 : " + (endTime - starttime)
     34                 + "ms" + " value:" + AtomicRun.atomicInteger);
     35     }
     36 
     37     /**
     38      * 加锁方法
     39      * 
     40      * @throws InterruptedException
     41      */
     42     private static void synMethod() throws InterruptedException {
     43         SynRun synRun = new SynRun();
     44         SynRun.endValue = M;
     45 
     46         ExecutorService service = Executors.newFixedThreadPool(N);
     47         long starttime = System.currentTimeMillis();
     48         for (int i = 0; i < N; i++) {
     49             service.submit(synRun);
     50         }
     51         service.shutdown();
     52         service.awaitTermination(Integer.MAX_VALUE, TimeUnit.SECONDS);
     53         long endTime = System.currentTimeMillis();
     54         System.out.println("有锁线程数量为 : " + N + " 开始时间为 : " + starttime
     55                 + " 结束时间为 : " + endTime + " 耗费时间为 : " + (endTime - starttime)
     56                 + "ms" + " value:" + AtomicRun.atomicInteger);
     57     }
     58 
     59     public static void main(String[] args) throws InterruptedException {
     60         System.out.println("当线程数量为 : " + N + "时:");
     61         atomicMethod();
     62         synMethod();
     63     }
     64 }
     65 
     66 /**
     67  * 
     68  * @author 秦孔祥
     69  * 
     70  */
     71 class AtomicRun implements Runnable {
     72 
     73     protected static AtomicInteger atomicInteger = new AtomicInteger();
     74     protected static int endValue;
     75 
     76     @Override
     77     public void run() {
     78         int startValue = atomicInteger.get();
     79         while (startValue < endValue) {
     80             startValue = atomicInteger.incrementAndGet();
     81         }
     82     }
     83 }
     84 
     85 class SynRun implements Runnable {
     86 
     87     protected static int startValue;
     88     protected static int endValue;
     89 
     90     @Override
     91     public void run() {
     92         while (startValue < endValue) {
     93             addValue();
     94         }
     95     }
     96 
     97     private synchronized void addValue() {
     98         startValue++;
     99     }
    100 }
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  • 原文地址:https://www.cnblogs.com/Cilimer/p/4021210.html
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