Whoa folks The concurrent low pause collector: this collector is used if
the -Xincgc is passed he concurrent collector is used to collect the
tenured generation and does most of the collection concurrently with the
execution of the application. The application is paused for short periods
during the collection. A parallel version of the young generation copying
collector is used with the concurrent collector. The concurrent low pause
collector is used if the option -XX:+UseConcMarkSweepGC is passed on the
command line. please check out
http://www.oracle.com/technetwork/java/gc-tuning-5-138395.html#0.0.0.Performance%20Considerations|outline
 really be worth your time.  I have sucessfulky on the z with websphere
and linux implemented GC - as any utility that interacts with applications
one must KNOW the application.  Heap sizes etc.

Richard (Gaz) Gasiorowski
Solution Architect
CSC
3170 Fairview Park Dr., Falls Church, VA 22042
845-889-8533|Work|845-392-7889 Cell|[email protected]|www.csc.com




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From:
Alan Cox <[email protected]>
To:
[email protected]
Date:
04/25/2011 04:39 PM
Subject:
Re: multipl cpu's



> One of the problems with Java Garbage Collection is that it halts
> other work in the JVM for the duration of the GC (because you're
> moving stuff around, you can't have people trying to use it). While GC
> has improved over time to reduce the amount of objects handled during
> each scan, my understanding is that it still suspends other JVM work.
> Part of GC can exploit additional CPUs when you activate the parallel
> GC (not the default).

Thats an implementation flaw (maybe flaw is a strong word given its a
hard problem).

Schoeberl and Puffitsch for one produced a mostly non blocking garbage
collection for Java which only blocks the threads it needs and only at the
points it has to. Rather useful for multi-threaded systems.

Alan

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