JEP 248: Make G1 the Default Garbage Collector

Jeremy Manson jeremymanson at
Tue Jun 2 05:22:18 UTC 2015

On Mon, Jun 1, 2015 at 6:04 PM, Kim Barrett <kim.barrett at> wrote:

> On Jun 1, 2015, at 7:04 PM, Jeremy Manson <jeremymanson at> wrote:
> >
> > - Part of the reason our CMS performs better is that we've made changes
> to
> > CMS to improve its performance.  We see roughly half as much CPU
> > utilization, and the long tail pause times have been cut dramatically.
> It
> > would be nice if we could upstream the changes (especially for us,
> because
> > they break with every new release, and we have to fix them!), but we've
> > never been able to find anyone at Oracle who has the bandwidth to do the
> > reviews.  For example, the response to this:
> >
> >
> >
> > was not hugely enthusiastic, and that's not even one of the more complex
> > changes.
> I’d be interested in looking at the mentioned card table scanning
> speedup.  But I completely
> missed that comment, buried as it is in the middle of a more or less
> unrelated discussion.  I’m
> going to go reply over there, since that technical problem doesn’t have
> anything to do with
> what’s being discussed here.

Excellent!  In that case, my interjection here was completely worth my
time.  Jungwoo is out until Wednesday, but I'll make sure he sees it.


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