如何使这个Java延迟webservice调用代码使用更少的CPU？

Question

我一直在对我的应用程序进行一些cpu分析，并且我注意到需要花费大量时间的事情之一是确保我每秒向webservice发送mo而不是查询的代码。实际的查询本身和结果的处理相比之下花费的时间很少，当然有一个I / O组件在等待结果，但我想要做的是减少cpu，因为应用程序有时必须在单个cpu机器上运行

使用YourKit Profiler，使用大量CPU的调用是

 java.util.concurrent.locks.AbstractQueuedSynchronizer.aquireQueued()

我的延迟方法如下

    public class SearchServer
    {

        private static java.util.concurrent.locks.Lock delayLock = new ReentrantLock();
        private static AtomicInteger queryQueue = new AtomicInteger();
        private static AtomicLong queryDelay = new AtomicLong();

        static void doDelayQuery()
        {
            delayLock.lock();
            try
            {
                if(isUserCancelled())
                {
                    return;
                }
                //Ensure only send one query a second
                Date currentDate = new Date();
                long delay = currentDate.getTime() - querySentDate.getTime();
                if (delay < delayInMilliseconds)
                {
                    try
                    {
                        long delayBy = delayInMilliseconds - delay;
                        queryDelay.addAndGet(delayBy);
                        Thread.sleep(delayBy);
                        logger.info(Thread.currentThread().getName() + ":Delaying for " + delayBy + " ms");
                    }
                    catch (InterruptedException ie)
                    {
                        Thread.currentThread().interrupt();
                        throw new UserCancelException("User Cancelled whilst thread was delay sleeping");
                    }
                }
            }
            finally
            {
                //We set before unlocking so that if another thread enters this method before we start query we ensure they
                //do not skip delay just because the query that this thread has delayed for has started
                querySentDate = new Date();
                delayLock.unlock();
            }

        }
    }

Answer 1

好吧，使用谷歌番石榴库，结果非常简单

import com.google.common.util.concurrent.RateLimiter;
public class SearchServer
{
     private static RateLimiter rateLimiter = RateLimiter.create(1.0d);

     static void doDelayQuery()
     {
        rateLimiter.acquire();
     }

     public doQuery()
     ..................
}

虽然之前的关键区别是我花了前一次调用的时间所以没有在调用之间等待整秒，所以为了得到类似的吞吐量，我改变了RateLmiter使用2.0d

分析不再显示该区域的cpu命中率。