RFR: 8033426: Scale initial NewSize using NewRatio if not set on command line

Jesper Wilhelmsson jesper.wilhelmsson at oracle.com
Mon Feb 3 08:50:18 PST 2014


Hi Stefan,

Have you looked at how this change plays with the ergonomics for NewSize in 
Arguments::set_cms_and_parnew_gc_flags()? That code will also use NewRatio to 
scale NewSize, but if running with a large CMSYoungGenPerWorker it may end up 
with a larger NewSize. Looks like your change will handle it well, but it would 
be nice with some test to verify it going forward.

Anyways, looks good to me.
Ship it!
/Jesper


Stefan Johansson skrev 3/2/14 4:40 PM:
> Hi,
>
> Can I have a couple of reviews for this enhancement:
> https://bugs.openjdk.java.net/browse/JDK-8033426
>
> Webrev:
> http://cr.openjdk.java.net/~sjohanss/8033426/webrev.00/
>
> Summary:
> Currently the initial young generation size is the same as the minimum. If not
> using large pages this will be 1.5M for the default collector regardless of how
> large the whole heap is. The proposed change is to scale the initial young size
> the same way the maximum young size is scaled, using the NewRatio parameter.
>
> Note:
> This change has been out on review as part of the fix for JDK-8028498, but after
> discussions we have decided take another approach for that bug.
>
> Testing:
> * JPRT
> * GC tests in jtreg
>
> Thanks,
> Stefan


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