On 6 May 2011 16:35, Mark Thomas <ma...@apache.org> wrote: > On 06/05/2011 16:24, Phil Steitz wrote: >> On 5/6/11 3:43 AM, Mark Thomas wrote: >>> Before I go too far down the road of the re-writing the core object >>> allocation code for pool2, I'd like to get some clarity on what the >>> minimum Java version targeted by pool2 should be. >> >> It is also logical to ask at this point if the rewrite is desirable >> / necessary and what we expect to gain from it. I have pretty >> consistently advocated this, but given the work and inevitable >> stabilization required, we should at least ask the question. Seems >> to me the goals should be 0) performance 1) maintainability 2) >> robustness 3) (configurable?) fairness. Do you agree with these and >> are you sure the rewrite is necessary to get them? > > Yes I agree. To address 0), we need to remove most/all of the > synchronisation around object allocation. That means a re-write, almost > certainly with java.u.c. I still have concerns around 1) & 2). The more > I think about this problem, the more I realise I need to spend more time > thinking about the problem. At the moment, I would rather take the time > and get this right. > >>> It is currently 1.5. >>> >>> It would make the implementation of the FIFO/LIFO allocation option >>> considerably easier if that was changed to 1.6. >> >> Can you explain a little what the problem is? > > Sure. In pool1 we have the ability (via CursorableLinkedList) to remove > and insert idle objects at any point in the queue. We use this for the > evictor and idle validation. It we switch to java.u.c (and I think it is > almost certain we will have to to get the performance we want) there are > far fewer options over object insertion/creation.
I can see why removal of arbitrary entries is needed, but why do we need insertion of elements other than at head or tail? > In Java 1.5, LinkedBlockingQueue only supports FIFO. It is not possible > to remove from the tail of the queue or insert at the head. That makes > LIFO pretty much impossible to implement. > > In Java 1.6, LinkedBlockingDeque allows inserts and removals at either > end of the queue. That solves the LIFO/FIFO issue but not the eviction / > idle validation questions. I have some ideas about this but I am trying > to avoid creating lots of complexity. I am also mulling over how to > ensure that maxActive and friends are adhered to. > > Mark > > > > --------------------------------------------------------------------- > To unsubscribe, e-mail: dev-unsubscr...@commons.apache.org > For additional commands, e-mail: dev-h...@commons.apache.org > > --------------------------------------------------------------------- To unsubscribe, e-mail: dev-unsubscr...@commons.apache.org For additional commands, e-mail: dev-h...@commons.apache.org
