JEP 144: Reduce GC Latency for Large Heaps

Todd Lipcon todd at cloudera.com
Tue Feb 28 16:18:25 PST 2012


Hi Mark, G1 team,

Do you have any plans to address either of the problems discussed in
the thread "G1GC Full GCs" from January '11?

To refresh/summarize, the problems were:
1) If the process is context-switched out during the "Other time"
accounting, and this causes the "other time" to eclipse the pause time
goal, then it will never again select any non-young regions for
collection until the next full GC.
http://mail.openjdk.java.net/pipermail/hotspot-gc-use/2011-January/000781.html
There's a simple patch linked above which solved this problem for my usecase.

2) If a region, at any time during its lifetime, overflows its fine
rset accounting, it's easy for it to become uncollectable despite a
very high garbage ratio:
http://mail.openjdk.java.net/pipermail/hotspot-gc-use/2011-January/000785.html
I worked on some patch for this but wasn't able to get good results in
the day or two that I allotted.

-Todd

On Tue, Feb 28, 2012 at 4:01 PM,  <mark.reinhold at oracle.com> wrote:
> Posted: http://openjdk.java.net/jeps/144
>
> - Mark



-- 
Todd Lipcon
Software Engineer, Cloudera


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