Project proposal: Shenandoah

Jon Masamitsu jon.masamitsu at
Fri Feb 27 18:07:55 UTC 2015


My impression of Shenandoah was that it would be a project
developed and maintained by Redhat and (I don't recall where
this last part of my recollection comes from) that it would be kept
separate from the OpenJDK hotspot sources.    Is that all


On 2/19/2015 10:42 AM, Roman Kennke wrote:
> I'd like to discuss the creation of the project Shenandoah with myself
> *and/or* Christine Flood as initial lead and the Hotspot group as
> sponsoring group.
> It's aim is to implement a new garbage collector that reduces GC pause
> times for applications that require really large heaps. Existing GCs
> show pause times of several 100ms up to several seconds on heaps >
> 100GB. That is because they need to stop all Java threads for compacting
> the heap. Shenandoah implements a new algorithm that allows to compact
> heap while only stopping the Java threads briefly for root scanning, and
> then evacuates the heap concurrently. This makes pause times unrelated
> to the heap size and only proportional to the root set size.
> Shenandoah has so far been developed as part of the IcedTea project:
> It has usable implementations for OpenJDK9 and OpenJDK8.
> Roman Kennke (me) is Principle Software Engineer at Red Hat, working on
> Shenandoah since two years now. Before this, he worked on Thermostat,
> and contributed to OpenJDK in several areas, most importantly the Zero
> and Shark ports, graphics, and ports to embedded platforms.
> Christine H. Flood is a prinicpal software engineer at Red Hat.  Most
> recently she's been working on Shenandoah, before that she worked at
> Oracle/Sun labs on the  Fortress programming language,  and on JVM
> Scalability. She's one of the inventors of both the parallel GC
> algorithm and G1.
> Initial committers and reviewers would be me and Christine.
> Could we both be project leads? Christine doesn't have an OpenJDK
> idendity yet...
> Best regards,
> Roman

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