RFR: Partial GC: Implement work-stealing and rehash queue work

[Zhengyu Gu]

Can easily add Terminator there, will it make difference?

-Zhengyu

On 03/16/2017 02:18 PM, Aleksey Shipilev wrote:
> Hi,
>
> This change implements work-stealing in partial GC. It also *first* processes
> all roots and root regions to keep threads busy, and *then* dives into queue
> draining work.
>
> Webrev:
>   http://cr.openjdk.java.net/~shade/shenandoah/partial-workstealing/webrev.01/
>
> Testing: hotspot_gc_shenandoah, cursory jcstress -m quick
>
> TreeFragger before:
>   [60.209s][info][gc,stats] Partial GC =
>     24.48 s (a =   844209 us) (n =    29)
>       (lvls, us =   349609,   369141,   445312,  1660156,  1865855)
>
> TreeFragger after:
>   [57.090s][info][gc,stats] Partial GC =
>      8.28 s (a =   201969 us) (n =    41)
>       (lvls, us =    77734,    91211,   138672,   371094,   436511)
>
> Thanks,
> -Aleksey
>