JEP 248: Make G1 the Default Garbage Collector

Kim Barrett kim.barrett at
Tue Jun 2 01:04:36 UTC 2015

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.

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