RFR: 8224659: Parallel GC: Use WorkGang (1: PCRefProcTask)

[Peter B. Kessler]

On Fri, 24 May 2019 13:25:47 +0200 Leo Korinth <leo.korinth at oracle.com> wrote
> Subject: RFR: 8224659: Parallel GC: Use WorkGang (1: PCRefProcTask)
> 
> Here is the first patch in a proposed patch series of eight that
> removes gcTaskManager and uses the WorkGang abstraction instead.
> ....
> Performance numbers seems to indicate
> that we go from roughly no improvements up to more than
> 40% improvements (!). Regressions seems rare. Performance improvements
> are primary in the young collections.
> ....

I assume the performance you cite is in the collection times, not overall application performance improvement.  Do you know if the improvement is in the actual parceling out of the work, or better balancing of the parceled out work among the workers, or in the termination algorithm, or whatever?  What causes the rare regressions?  E.g., is there something adversarial about the object graphs, or something else we should be on the lookout for?

			... peter