Wow, I did not know that about TPE. I need to go fix some code... I withdraw my advocacy for switching TaskManager to use TPE.
Chris -----Original Message----- From: Gregg Wonderly [mailto:[email protected]] Sent: Thursday, June 10, 2010 1:07 AM To: [email protected] Subject: Re: com.sun.jini.thread lock contention As was kind of discussed earlier, TPE uses max threads in a different way then most people would think. It creates up to min threads, as long as the "queue is not full" (offer() succeeding is "not full"). When the queue is "full", it creates up to maxPoolSize threads for (maxPoolSize-corePoolSize) more adds. So for an open ended queue, maxPoolSize has no meaning, and only corePoolSize threads will ever be created it looks to me. I think there are still bugs to be fixed and behavior to be better defined in TPE in particular. I'm all for using the interfaces in j.u.c that make sense to use. But I am a bit worried about swapping out TaskManager for TPE without a lot more studying around the exact behaviors and failure modes, which might help identify some issues we need to address overall regarding how threads are managed. For example, the default life of 15mins on threads created by TaskManager in its current version, seems extreme. 15 seconds would be much better for resource management I think. Gregg Wonderly Patrick Wright wrote: > One point I'd like to raise about using java.util.concurrent and TPE: > I think that over the long term, it makes sense to (re)use existing > utilities which are being maintained by domain experts rather than > custom utilities you've written yourself. The concurrent libraries > available since Java 5 were written and maintained by people widely > recognized to be very, very good at a very hard problem. That doesn't > mean they, or the library, is perfect, just that there is value in > building on their work and letting them take care of the bugs and > optimizations over time. The downside would be that if a River user > was stuck with, say, Java 5, they couldn't take advantage of bugfixes > or improvements in Java 6. On the other hand, that's true of the > entire JDK. > > The max threads issue seems to me a non-issue. A JVM can allocate only > so many native threads before it runs out of OS resources; that's a > hard limit. You can set a max of Integer.MAX_VALUE but your VM would > die long, long before it reached that. > > For me this is more of design policy decision. Re-use, intelligently > and selectively, where possible, to reduce your project's workload. > > > Patrick >
