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J2SE 5.0_05 has significant performance improvements

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dagastine
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Joined: 2003-06-19
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J2SE 5.0_05 is now available!
http://java.sun.com/j2se/1.5.0/download.jsp

J2SE 5.0_05 is the latest Tiger update release and includes several performance optmizations. Here a few of that we're particularly happy about.

Large Page Support for Solaris, Linux, and Windows.

J2SE 5.0_05 adds large pages support to Linux and Windows. To enable on these platforms use: -XX:+UseLargePages. This feature is on by default on Solaris 10. For detailed instructions see:
http://java.sun.com/docs/hotspot/VMOptions.html
(bottom of the page)

System.arraycopy optimizations on SPARC and x64

System.arraycopy optimizations first identified on x64 platforms have now been extended to include SPARC platforms as well.

Lock Coarsening

The J2SE 5.0_05 server compiler includes simple lock coarsening. This is the first phase of our uncontended synchronization performance improvements coming in upcoming update releases.

Continued J2SE API Performance Improvments

J2SE 5.0_05 includes many improvements to the J2SE API. This is part of Sun continued performance work, expect to see more improvments in upcoming updates as well.

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jseltzer
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Joined: 2003-06-12
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I just noticed something with 1.5.0_04. I'm not sure how long this has been around but I think it's way cool. I ran the swingset demo on my windows xp machine and also launched the windows task mgr. I was surprised to see what happened when I minimized the demo. The memory it was using dropped from 30 megs to 1 meg and stayed there.

I know what you're thinking. If I restore the window, I'll have to watch it slowly repaint.....Wrong. It restores perfectly without any delay to user interaction. By the way, I noticed that internet explorer behaves the same way.

Am I crazy or is this a new performance feature? Having multiple java desktop apps running at the same time looks possible now.

Message was edited by: jseltzer

cowwoc
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Joined: 2003-08-24
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The memory drop on minimize was always there. It's a WindowsNT thing which you can reproduce with Notepad as well. It's actually a bad thing for Java because very often task-manager will show a Java application using 30MB of memory when only 1-2MB is really allocated. Try to explain to end-users that task-manager is lieing to them and they have to minimize the window to get an accurate reading

linuxhippy
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Joined: 2004-01-07
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> The J2SE 5.0_05 server compiler includes simple lock
> coarsening. This is the first phase of our
> uncontended synchronization performance improvements
> coming in upcoming update releases.

Are here any numbers how many % of uncontended locks in "typical" server software can be saved?
Of course this highly depends on how the software is written - but _any_ numbers would be quite interresting.

Another topic related to this, have there been any problems with less granularity showed up - coarsing meens locks are hold longer - and maybe block other threads?

Thanks, lg Clemens

dagastine
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Joined: 2003-06-19
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I don't have general statistics on locks elimiated by coarsening. You can measure this for yourself by using the Mustang development debug binaries found here:
http://download.java.net/jdk6/binaries/

Use the following flags with the latest debug binary:
-XX:+PrintLockStatistics
-XX:+PrintEliminateLocks

Note: Mustang has *all* of the features we plan to add to upcoming Tiger updates, plus a few more that we haven't mentioned yet :-)

linuxhippy
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> -XX:+PrintLockStatistics
> -XX:+PrintEliminateLocks
Thats really good to know - maybe this could even help in optimizing my contended locks away from my server-app ;-)

Thanks for sharing this, lg Clemens

tmarble
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Joined: 2003-08-22
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Thanks Dave!

Let me add that these improvements allowed us
to post record-breaking results as part of our
Launch of the SunFire X2100, X4100 and X4200:

http://www.sun.com/x64/05q3/benchmarks.html

Regards,

--Tom