Spin Loop Hint support: Draft JEP proposal

Doug Lea dl at cs.oswego.edu
Tue Oct 6 20:02:04 UTC 2015

On 10/04/2015 12:22 PM, Gil Tene wrote:
> I would like to circulate this draft JEP proposal for initial review and consensus building purposes.

Some background: about two years ago, Dave Dice and I put together
a pre-jep proposal for JVM support for recent CPU features covering:

(1) MWAIT/PAUSE/etc (for spins as well as other uses people have noted);
(2) Core topology/neighborhood information and;
(3) 2CAS, as a foothold on HTM that could still be reasonably efficient
on non-transactional processors.

My understanding of the result of this effort was that Oracle JVM engineers
didn't think they had resources to do this for jdk9. It didn't occur to
me that non-Oracle contributors might want to cherry-pick one (some
of (1) above). It seems plausible to do this, but only if designed
as the first of some possible enhanced support along these lines.


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