Re: System wide JVMs

[Blair Wyman <blairw@xxxxxxxxxx>]

David and Marc,

Actually, the iSeries' GC algorithm does NOT stop mutator threads while
marking collectable objects.

(Now, the GC threads must "handshake" with each other at a few points in
the GC cycle, to ensure that the color of newly-allocated objects is set
correctly, but "stop the world" is only done in the most extremely
memory-constrained situations.)

HTH.

-blair


  ___   _           Blair Wyman                  IBM Rochester
 ( /_)  /  _  ' _   (507)253-2891            blairw@xxxxxxxxxx
__/__)_/_<_/_/_/_'  Opinions expressed may not be those of IBM



                                                                           
             "David Morris"                                                
             <David.Morris@plu                                             
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                                       Re: System wide JVMs                
             07/07/2004 05:17                                              
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Marc,

All Garbage Collection algorithms stop everything while marking
collectable objects. IBM has been way ahead of Sun in minimizing the
time that everything stops. Sun recently improved their garbage
collection support with 1.4.1 to be more on par with IBM and the
concurrent collector sounds closer to what IBM has been doing. A lot
depends on your hardware and application so you have to test to find out
what works best. Sun's defaults are way off for most applications I have
tuned and IBM and BEA's are generally closer.

David Morris

>>> spam1@xxxxxxxxxxxx 7/7/2004 3:23:00 PM >>>
Blair Wyman wrote:
> Not sure where you heard that "the iSeries JVM actually pauses
execution in
> the JVM to do clean up," but it's simply not the case.  In fact, the
> asynchronous nature of the iSeries' GC algorithms helped push us to
our
> early domination of the specJBB benchmark.


JVMs on every Platform do GC in a seperate Thread and are of
asynchronous nature, so its not very iSeries specific, or did i
misunderstood something here?

Marc Logemann
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