Re: Tradeoffs between ConcurrentLinkingQueue and LinkedBlockingQueue

Sebastian Millies <>
Wed, 29 Sep 2010 10:28:23 +0200
Am 29.09.2010 03:06, schrieb Kevin McMurtrie:

Forget polling. There's no way to guarantee a good tradeoff between
latency and CPU cost.

LinkedBlockingQueue and ArrayBlockingQueue may not be the best
performers. They use ReentrantLock, which currently performs worse than
a plain synchronized block. It's possible for a synchronized LinkedList
with wait()/notify() to perform better.

ConcurrentLinkedQueue is a top performer for multiple threads and it
never blocks. If you have a single dedicated thread calling poll(), you
can easily suspend and resume that one thread using LockSupport.
LockSupport's performance depends on the OS kernel.


Thanks. Just to be sure, are you suggesting the following?

a) have a ConcurrentLinkedQueue:
         static Queue queue = new ConcurrentLinkedQueue<Request>();

b) Have a single consumer thread that is parked when the
    queue is empty:
         static Thread consumer = new Thread( new Runnable()
             public void run()
                 while( true ) {
                     Request req = queue.poll();
                     if( req != null ) {
                         doSomething( req );
                     else {
         } );

c) Have every producer thread unpark the consumer after gaving added
    an element to the queue:
       queue.offer( new Request() );
       LockSupport.unpark( consumer );

Additional question: From the javadoc, it wasn't entirely clear to me
what happens when a parked thread is interrupted?

-- Sebastian

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