G1 performance

Monica Beckwith monica.beckwith at oracle.com
Mon May 13 18:30:17 UTC 2013

Ramki -

Quick comments inlined -
On 5/8/2013 3:31 PM, Srinivas Ramakrishna wrote:
> I have been playing with G1 a bit, and have noticed a nearly 10%
> overhead with G1, which is independent of the measured GC overheads.
> It's possible that this is because of the G1 write barriers inhibiting
> certain JIT optimizations.
I think Jon already mentioned one of our findings on this. Here's the 
related CR: http://bugs.sun.com/view_bug.do?bug_id=7183509
> I have also seen, although this needs to be
> established more thoroughly, that G1's performance degrades the longer
> it runs, in the sense that minor GC pause times become progressively
> worse.
I would like to look at the logs, there could be issues like the following:

Thanks for starting this thread.

> Has this kind of performance behaviour been observed by others on this
> list? Or internally at Oracle in performance testing of G1? Or by
> other power users of G1 out there?
> Basically, all of the experiments I have done seem to indicate that
> CMS performs better than G1, but unfortunately the potential
> fragmentation problem with CMS (followed by the promotion failure
> handling and the single-threaded compaction to follow) make it
> unsuitable in certain situations.
> thanks!
> -- ramki

Oracle <http://www.oracle.com>
Monica Beckwith | Principal Member of Technical Staff
VOIP: +15124011274 <tel:+15124011274>
Oracle Java Performance

Green Oracle <http://www.oracle.com/commitment> Oracle is committed to 
developing practices and products that help protect the environment
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <https://mail.openjdk.java.net/pipermail/hotspot-gc-dev/attachments/20130513/a806ec72/attachment.htm>
-------------- next part --------------
A non-text attachment was scrubbed...
Name: oracle_sig_logo.gif
Type: image/gif
Size: 658 bytes
Desc: not available
URL: <https://mail.openjdk.java.net/pipermail/hotspot-gc-dev/attachments/20130513/a806ec72/oracle_sig_logo.gif>
-------------- next part --------------
A non-text attachment was scrubbed...
Name: green-for-email-sig_0.gif
Type: image/gif
Size: 356 bytes
Desc: not available
URL: <https://mail.openjdk.java.net/pipermail/hotspot-gc-dev/attachments/20130513/a806ec72/green-for-email-sig_0.gif>

More information about the hotspot-gc-dev mailing list