G1 is bad for me

Andrei Pozolotin andrei.pozolotin at gmail.com
Thu Feb 18 12:04:24 PST 2010


    Ramki, hello;

    thank you for the advice - I followed it;

    results:

    1) pauses now are 500 ms instead of 1000 ms;

    2) no crashes under production load after 30 minutes;

    progress!

    now I am looking for advice how to move pauses into 50 ms range
    and remove all-4-cpu stop the world 100% cpu load spikes;

    log attached;

    cheers,

    Andrei


-------- Original Message  --------
Subject: Re: G1 is bad for me
From: Y. Srinivas Ramakrishna <Y.S.Ramakrishna at Sun.COM>
To: Andrei Pozolotin <andrei.pozolotin at gmail.com>
Cc: hotspot-gc-use at openjdk.java.net
Date: Thu 18 Feb 2010 11:37:56 AM CST
> Hi Andrei -- please use the latest hs17 JVM which you can get from JDK
> 7. There have been
> many improvements (and bug fixes) since the 6u18/hs16 that you are
> using below.
> Most importantly, please add -XX:-ReduceInitialCardMarks to work
> around a regression
> introduced in 6u18/hs16, as described in the 6u18 release notes.
> As re optimal settings (these may be quite different from shapes that
> helped with CMS
> for example), i'll let others w/more (tuning and other) experience
> w/G1 comment.
>
> -- ramki
>
> On 02/18/10 08:56, Andrei Pozolotin wrote:
>>     Ramki, Jon, hi;
>>
>>     I read everyting I could find on G1:
>>     http://www.google.com/patents/about?id=j5SpAAAAEBAJ&dq=7,340,494
>>    
>> http://developers.sun.com/learning/javaoneonline/2008/pdf/TS-5419.pdf
>>     http://research.sun.com/jtech/pubs/04-g1-paper-ismm.pdf
>>     http://blogs.sun.com/sunabl/entry/the_new_g1_collector
>>     http://blogs.sun.com/jonthecollector/entry/our_collectors
>>     etc, etc, etc,
>>
>>     got myself excited - looks great on paper!
>>
>>     and I followed Albert's advice, while trying to mimic my CMS
>> settings:
>>     http://blogs.sun.com/sunabl/entry/the_new_g1_collector
>>
>>     -Xms3700m
>>     -Xmx3700m
>>     -XX:PermSize=50m
>>     -XX:MaxPermSize=50m
>>     -XX:+UnlockExperimentalVMOptions
>>     -XX:+UseG1GC
>>     -XX:G1YoungGenSize=900m
>>     -XX:SurvivorRatio=2
>>     -XX:+G1ParallelRSetUpdatingEnabled
>>     -XX:+G1ParallelRSetScanningEnabled
>>
>>     results:
>>
>>     1) pauses are 1000 milliseconds or more;
>>
>>     2) reproducible crashes after 3 minutes under load;
>>
>>     logs attached;
>>
>>     am I missing something obvious?
>>     like do I need to switch to older / specific JVM build?
>>
>>     per Tony, this was already working fine for a neighbour of mine
>> in 2008:
>>    
>> http://developers.sun.com/learning/javaoneonline/2008/pdf/TS-5419.pdf
>>
>>     Thank you;
>>
>>     Andrei
>>
>>
>> ------------------------------------------------------------------------
>>
>> _______________________________________________
>> hotspot-gc-use mailing list
>> hotspot-gc-use at openjdk.java.net
>> http://mail.openjdk.java.net/mailman/listinfo/hotspot-gc-use
>
>

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