[concurrency-interest] ThreadPoolExecutor workQueue concurrency issue

Doug Lea dl at cs.oswego.edu
Tue Dec 11 06:23:07 EST 2007

Guy Korland wrote:
> Hi,
> We built an application in a SEDA fashion, working in stages from one 
> ThreadPool to another.
> We found out that the BlockingQueue used by the ThreadPoolExecutor 
> became a major concurrency killer when we start working on 4 cores 
> machines and above.
> The thing is that we don't really need the strong FIFO behavior forced 
> by all the BlockingQueue implementations available, some kind of 
> fairness will be good enough.
> Any ideas?

You might consider trying LinkedTransferQueue that is out
in preliminary form in jsr166y. It eases up guarantees
to merely promise FIFOness wrt any given producer. Internally,
it extends some of the ideas from the java6 overhaul of
SynchronousQueue, and tends to have better throughput
under contention than LinkedBlockingQueue. In other words,
it was designed exactly to solve the problems you are seeing.
Javadoc at:
It is available in the jar for jsr166y listed at


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