G1 parallel old gen collection

charlie hunt charlie.hunt at oracle.com
Tue Oct 4 19:45:24 UTC 2016

> Is that still the case in JDK 9?


We need to figure out why you’re getting full GCs, and what to do to avoid them.

If you can share the GC logs from G1, and the command line options in use, we can probably help improve the situation for you. We will likely suggest enabling +PrintAdaptiveSizePolicy so we can see why G1 is making certain adaptive decisions.

> On Oct 4, 2016, at 2:37 PM, Christian Thalinger <cthalinger at twitter.com> wrote:
> First, I apologize if I get all the terminology wrong.  You know me… this is all a blackbox to me.
> I’m currently trying to run some Twitter services with G1 and the results are encouraging but not good enough.  One issue is that full GCs take much longer than with ParallelOld (3-4x longer).
> Tony said that G1’s old collection is not parallel.
> Is that still the case in JDK 9?  If yes, is someone at Oracle working on parallelizing it?

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