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山寨同步队列 VS 官方BT的ArrayBlockingQueue ,结果官方落马!!!

    博客分类:
  • java
阅读更多
官方的java.util.concurrent.ArrayBlockingQueue的性能是很BT的,我下午无聊然后就想去测试下到底有多BT就写了如下测试代码,也不知道是我的代码写的有问题还是怎么的啦,测试结果和我想的完全不一样。

条件:20个线程,存取线程各半,队列大小是30W,其他电脑配置啥的啊很大众化就不描述了。

耗时:
山寨版的:2400左右
官方版的:3400左右

--------------------------------------------------------------------------------------------
官方的java.util.concurrent.ArrayBlockingQueue 生产者消费者代码如下:
package thread;

import java.util.concurrent.ArrayBlockingQueue;
import java.util.concurrent.BrokenBarrierException;
import java.util.concurrent.CyclicBarrier;

public class ProducerCustomerQueue2<E> {
	public static void main(String[] args) throws InterruptedException {
		/**
		 * 20个线程,存取线程各半,队列大小是30W,耗时:2400左右
		 */
		int total = 300000, threadCount = 20,queueSize = 100;
		ArrayBlockingQueue<Integer> queue = new ArrayBlockingQueue<Integer>(queueSize);
		final long start = System.currentTimeMillis();
		CyclicBarrier barrier = new CyclicBarrier(threadCount, new Runnable() {
			public void run() {
				System.out.println("统计时间:"
						+ (System.currentTimeMillis() - start));
			}
		});
		for (int i = 0; i < threadCount >>> 1; i++) {
			new Thread(new ProducerThread2(queue, barrier, total)).start();
			new Thread(new CustomerThread2(queue, barrier, total)).start();
		}
	}

}

// 生产者线程
class ProducerThread2 implements Runnable {
	ArrayBlockingQueue<Integer> queue;
	CyclicBarrier barrier;
	int total;

	public ProducerThread2(ArrayBlockingQueue<Integer> queue,
			CyclicBarrier barrier, int total) {
		super();
		this.queue = queue;
		this.barrier = barrier;
		this.total = total;
	}

	public void run() {
		System.out.println("ProducerThread启动...");
		for (int i = 0; i < total; i++) {
			try {
				queue.put(i);
			} catch (InterruptedException e) {
				e.printStackTrace();
			}
		}
		try {
			System.out.println("ProducerThread完毕!");
			barrier.await();
		} catch (InterruptedException e) {
			e.printStackTrace();
		} catch (BrokenBarrierException e) {
			e.printStackTrace();
		}
	}
}

// 消费者线程
class CustomerThread2 implements Runnable {
	ArrayBlockingQueue<Integer> queue;
	CyclicBarrier barrier;
	int total;

	public CustomerThread2(ArrayBlockingQueue<Integer> queue,
			CyclicBarrier barrier, int total) {
		super();
		this.queue = queue;
		this.barrier = barrier;
		this.total = total;
	}

	public void run() {
		System.out.println("CustomerThread启动...");
		for (int i = 0; i < total; i++) {
			Object o;
			try {
				o = queue.take();
			} catch (InterruptedException e) {
				e.printStackTrace();
			}
		}
		try {
			System.out.println("CustomerThread完毕!");
			barrier.await();
		} catch (InterruptedException e) {
			e.printStackTrace();
		} catch (BrokenBarrierException e) {
			e.printStackTrace();
		}
	}
}




自己实现的同步队列如下:
package thread;

import java.util.concurrent.BrokenBarrierException;
import java.util.concurrent.CyclicBarrier;

public class ProducerCustomerQueue<E> {
	public static void main(String[] args) throws InterruptedException {
		/**
		 * 20个线程,存取线程各半,队列大小是30W,耗时:2400左右
		 */
		int total = 300000, threadCount = 20, queueSize = 100;
		ProducerCustomerQueue<Integer> queue = new ProducerCustomerQueue<Integer>(
				queueSize);
		final long start = System.currentTimeMillis();
		CyclicBarrier barrier = new CyclicBarrier(threadCount, new Runnable() {
			public void run() {
				System.out.println("统计时间:"
						+ (System.currentTimeMillis() - start));
			}
		});
		for (int i = 0; i < threadCount >>> 1; i++) {
			new Thread(new ProducerThread(queue, barrier, total)).start();
			new Thread(new CustomerThread(queue, barrier, total)).start();
		}
	}

	private Object lock = new Object();
	private final E[] array;
	private int putIndex;
	private int takeIndex;
	private int count;

	public synchronized int size() {
		return count;
	}

	public ProducerCustomerQueue(int n) {
		array = (E[]) new Object[n];
	}

	/**
	 * 将指定的元素插入到此队列的尾部(如果立即可行且不会超过该队列的容量),在成功时返回 true,如果此队列已满,则返回 false。
	 * 
	 * @param o
	 */
	public boolean offer(E o) {
		if (o == null) {
			throw new NullPointerException();
		}
		synchronized (lock) {
			if (count == array.length) {// 队列已满
				return false;
			} else {
				insert(o);
				return true;
			}
		}
	}

	/**
	 * 将指定的元素插入此队列的尾部,如果该队列已满,则在到达指定的等待时间之前等待可用的空间。
	 * 
	 * @param o
	 * @throws InterruptedException
	 */
	public boolean offer(E o, long timeout) throws InterruptedException {
		if (o == null) {
			throw new NullPointerException();
		}
		synchronized (lock) {
			if (count == array.length) {// 队列已满
				lock.wait(timeout);
			}

			if (count == array.length) {
				return false;
			} else {
				insert(o);
			}
		}
		return false;
	}

	/**
	 * 将指定的元素插入此队列的尾部,如果该队列已满,则等待可用的空间。
	 * 
	 * @param o
	 * @throws InterruptedException
	 */
	public void put(E o) throws InterruptedException {
		synchronized (lock) {
			while (count == array.length) {// 队列已满
				// System.out.println("put wait");
				lock.wait();
			}
			insert(o);
		}
	}

	private void insert(E o) {
		array[putIndex] = o;
		putIndex = (++putIndex == array.length) ? 0 : putIndex;
		count++;
		lock.notify();
	}

	/**
	 * 获取并移除此队列的头,如果此队列为空,则返回 null。
	 */
	public E poll() {
		synchronized (lock) {
			if (count == 0) {// 空队列
				return null;
			}
			return extract();
		}
	}

	/**
	 * 获取并移除此队列的头部,在指定的等待时间前等待可用的元素(如果有必要)。
	 * 
	 * @throws InterruptedException
	 */
	public E poll(long timeout) throws InterruptedException {
		synchronized (lock) {
			if (count == 0) {// 空队列
				lock.wait(timeout);
			}
			if (count == 0) {
				return null;
			} else {
				return extract();
			}
		}
	}

	/**
	 * 获取并移除此队列的头部,在元素变得可用之前一直等待(如果有必要)。
	 * 
	 * @return
	 * @throws InterruptedException
	 */
	public E take() throws InterruptedException {
		synchronized (lock) {
			for (;;) {
				if (count == 0) {// 空队列
					lock.wait();
				} else {
					return extract();
				}
			}
		}
	}

	private E extract() {
		E o = array[takeIndex];
		takeIndex = (++takeIndex == array.length) ? 0 : takeIndex;
		count--;
		lock.notify();
		return o;
	}
}

// 生产者线程
class ProducerThread implements Runnable {
	ProducerCustomerQueue queue;
	CyclicBarrier barrier;
	int total;

	public ProducerThread(ProducerCustomerQueue queue, CyclicBarrier barrier,
			int total) {
		super();
		this.queue = queue;
		this.barrier = barrier;
		this.total = total;
	}

	public void run() {
		System.out.println("ProducerThread启动...");
		for (int i = 0; i < total; i++) {
			try {
				// System.out.println("ProducerThread.." + queue.size());
				queue.put(i);
			} catch (InterruptedException e) {
				e.printStackTrace();
			}
		}
		try {
			System.out.println("ProducerThread完毕!");
			barrier.await();
		} catch (InterruptedException e) {
			e.printStackTrace();
		} catch (BrokenBarrierException e) {
			e.printStackTrace();
		}
	}

}

// 消费者线程
class CustomerThread implements Runnable {
	ProducerCustomerQueue queue;
	CyclicBarrier barrier;
	int total;

	public CustomerThread(ProducerCustomerQueue queue, CyclicBarrier barrier,
			int total) {
		super();
		this.queue = queue;
		this.barrier = barrier;
		this.total = total;
	}

	public void run() {
		System.out.println("CustomerThread启动...");
		for (int i = 0; i < total; i++) {
			Object o;
			try {
				o = queue.take();
			} catch (InterruptedException e) {
				e.printStackTrace();
			}
		}
		try {
			System.out.println("CustomerThread完毕!");
			barrier.await();
		} catch (InterruptedException e) {
			e.printStackTrace();
		} catch (BrokenBarrierException e) {
			e.printStackTrace();
		}
	}
}



补充:
为什么synchronized反而比ReentrantLock还要快?这个问题终于自己找到了答案。

jdk.16下synchronized和ReentrantLock的速度差不多,似乎还快一些,但是synchronized的缺点很多 ,参考http://houlinyan.iteye.com/blog/1112535两者的对比。
jdk1.5下ReentrantLock快synchronized接近9-10倍(非专业测试仅供参考)。

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