On May 17, 2007, at 3:41 PM, Marc Prud'hommeaux wrote:

I recall Patrick was looking into replacing some of our slower Map plumbing recently. If he is still working on that, it would be interesting to see if these could be dropped in to see what the performance differences were.

From the presentation I believe it really helps to have a 400+ core machine and lotsa threads to see the performance differences, which are then rather dramatic :-). Also the current implementation uses some com.sun classes (unsafe??) for CAS instructions and I got the impression that it uses slightly more memory than ConcurrentHashMap.

Looking forward to the results :-)

david jencks

On May 16, 2007, at 9:21 PM, Craig L Russell wrote:

Don't know if anyone caught Cliff's preso at Java One...

Anyone want to take a look at the new HashMap?


Begin forwarded message:

From: Kin-man Chung
Date: May 15, 2007 11:24:38 AM PDT
Subject: Lock-free HashMap

Cliff Click talked about his lock-free HashMap at JavaOne, and
demonstrated its superior scalability over ConcurrentHashMap.
The source is available at


We should check this out and see if it can be used in Glassfish to
boost the spec numbers.


Craig Russell
Architect, Sun Java Enterprise System http://java.sun.com/products/ jdo
408 276-5638 mailto:[EMAIL PROTECTED]
P.S. A good JDO? O, Gasp!

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