[Building Sakai] GC for Java 7

[Aaron Zeckoski]

I would probably set the pause to a second or less with the garbage
first collector but otherwise I definitely agree. Simpler is usually
best (and recommended) with JVM options in java 6 and 7. The
recommendation seems to generally be that you give the ergonomics
engine some parameters (like the MaxGCPauseMillis) and then let it
tune itself. You could even let it pick the GC engine that it uses.

-AZ


On Mon, Sep 9, 2013 at 1:58 AM, Stephen Marquard
<stephen.marquard at uct.ac.za> wrote:
> We are using the new(ish) G1 collector with java 7:
>
>  -XX:+UseG1GC -XX:MaxGCPauseMillis=3000
>
> which works reasonably all, although it doesn't always stick to MaxGCPauseMillis. The worst case full GC pause we've seen is 50s (on a heap size of around 5G) though that is quite rare.
>
> Regards
> Stephen
>
> ________________________________________
> From: sakai-dev-bounces at collab.sakaiproject.org [sakai-dev-bounces at collab.sakaiproject.org] on behalf of Sobieralski, Damian Michael [dsobiera at indiana.edu]
> Sent: 09 September 2013 04:10 AM
> To: sakai-dev at collab.sakaiproject.org
> Subject: [Building Sakai] GC for Java 7
>
> When we were running pre Java 7, it was determined these to be our JAVA_OPTS (in part) for GC.  We are noticing that lately (we are running Java 7) that GC seems to be functioning in a less than efficient way.
>
> What we had for pre Java 7:
>
> -Xmn2g -XX:+UseParNewGC -XX:+UseConcMarkSweepGC  -XX:+CMSParallelRemarkEnabled -XX:+ParallelRefProcEnabled -XX:ReservedCodeCacheSize=192m
>
> A lot of these are black box incantations to me. Do these setting look optimal/useful for Java 7?
>
> - Damian
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-- 
Aaron Zeckoski - Software Architect - http://tinyurl.com/azprofile