Request for Review (M) - 8150994: UseParallelGC fails with UseDynamicNumberOfGCThreads with specjbb2005
jon.masamitsu at oracle.com
Sat Apr 30 01:50:59 UTC 2016
Webrev updated for code review comment.
Sorry, I muffed the webrev delta but this is the only change (removal
of the assertion).
< assert(which <= parallel_gc_threads,
< "Inconsistent number of workers");
Thanks again, Thomas and Kim.
On 4/12/2016 8:50 PM, Jon Masamitsu wrote:
> The ParallelGC collector compacts by moving live objects from source
> regions to destination regions. The destination regions are regions
> that have
> been emptied of live objects and the source regions are regions that hold
> the original locations of the live objects. When a source region is
> it becomes a destination region. At the start of the compaction the
> destination regions are distributed to per thread lists processed by
> the GC
> workers. The original implementation had tasks that drain the initial
> destination lists and tasks that steal destination regions from other
> GC workers. The draining tasks and stealing tasks shared the per thread
> lists of destination regions. The bug was that the sharing was not
> synchronized correctly.
> See  for more details.
> The fix is to combine the draining tasks and stealing tasks so that
> sharing of the destination lists is not needed.
>  https://bugs.openjdk.java.net/browse/JDK-8150994
>  http://cr.openjdk.java.net/~jmasa/8150994/webrev.00/
More information about the hotspot-gc-dev