RFR: OWST implementation

[Roman Kennke]

Ok, ready to go!

For bonus points, fix indentation? (No need for another review).

Roman

Am Mittwoch, den 02.11.2016, 10:54 -0400 schrieb Zhengyu Gu:
> Make it experimental.
> 
> Webrev: http://cr.openjdk.java.net/~zgu/owst/webrev.02/
> 
> Thanks,
> 
> -Zhengyu
> 
> 
> On 11/02/2016 09:55 AM, Roman Kennke wrote:
> > 
> > Ok great!
> > 
> > Do you think it may be useful to choose one or the other impl based
> > on
> > an experimental flag? E.g. -XX:+UseShenandoahOWST ?
> > 
> > Roman
> > 
> > Am Mittwoch, den 02.11.2016, 09:36 -0400 schrieb Zhengyu Gu:
> > > 
> > > Based on Roman's suggestion, subclass ParallelTaskTerminator to
> > > avoid
> > > invasive changes to ParallelTaskTerminator.
> > > 
> > > Webrev: http://cr.openjdk.java.net/~zgu/owst/webrev.01/index.html
> > > 
> > > Tests: jtreg shenandoah tests, SPECjbb and modified TestGCOld and
> > > GCBasher.
> > > 
> > > Thanks,
> > > 
> > > -Zhengyu
> > > 
> > > 
> > > On 11/01/2016 06:07 PM, Zhengyu Gu wrote:
> > > 
> > > > 
> > > > Yes, it should be a subclass. I will redo the implementation.
> > > > 
> > > > Thanks,
> > > > 
> > > > -Zhengyu
> > > > 
> > > > 
> > > > On 11/01/2016 05:00 PM, Roman Kennke wrote:
> > > > > 
> > > > > Hi Zhengyu,
> > > > > 
> > > > > I can't say much about correctness etc of the algorithm.
> > > > > However,
> > > > > this
> > > > > affects shared code, and other GCs that also use taskqueue.
> > > > > This
> > > > > probably means they benefit from improved performance too,
> > > > > but it
> > > > > also
> > > > > means they'd suffer from any bugs that are in it. I wouldn't
> > > > > want
> > > > > to
> > > > > make that choice for them. :-) Would it be possible to
> > > > > somehow
> > > > > either
> > > > > fork taskqueue into a new class, or, if possible, abstract
> > > > > the
> > > > > new/changed behaviour? Bonus points for making the impl
> > > > > swappable, so
> > > > > that Shenandoah could use one or the other taskqueue. This
> > > > > would
> > > > > 1.
> > > > > make it possible to compare them and 2. smooth the
> > > > > transition,
> > > > > i.e.
> > > > > make the new queue enabled by an experimental flag, etc.
> > > > > Would
> > > > > that be
> > > > > possible?
> > > > > 
> > > > > Cheers,
> > > > > Roman
> > > > > 
> > > > > Am Dienstag, den 01.11.2016, 11:15 -0400 schrieb Zhengyu Gu:
> > > > > > 
> > > > > > This is the initial implementation of OWST, which is pretty
> > > > > > closely
> > > > > > following Google's paper.
> > > > > > 
> > > > > > I intend to minimize the changes in the changeset, due to
> > > > > > recent
> > > > > > regression SPECjbb number.
> > > > > > I think there are areas we can improve the implementation.
> > > > > > For
> > > > > > example, to have spin master give up
> > > > > > its role before goes into sleep, so other worker who
> > > > > > detects
> > > > > > new
> > > > > > tasks, may wake up waiting workers, etc.
> > > > > > 
> > > > > > 
> > > > > > Webrev: http://cr.openjdk.java.net/~zgu/owst/webrev.00/
> > > > > > 
> > > > > > Thanks,
> > > > > > 
> > > > > > -Zhengyu
> > > > > > 
> 
>