Call For Discussion: New Project: Atlantis

Thomas Stüfe thomas.stuefe at
Tue Nov 20 14:38:30 UTC 2018

In general I like this, it is certainly worth a try.

In an ideal world, there would be no need for this: serviceability-dev
would be the place to be, full of both knowledgeable outsiders and
friendly reviewers with lots of spare time on their hand :) however,
in reality we do not have that many outsiders (those who are here are
valuable, but they are few), and we lack reviewers.

By concentrating discussions on larger features into an own project
with an own mailing list maybe we could speed up incubation of larger
features, especially when contributed from outside Oracle. Similar
important is speedy rejection for features that just do not fit, since
it can save time and hurt on the contributors side.

I'm worried about fragmentation though. Once we have this project,
what is then the role of serviceability-dev? Just smallish everyday
fixes? Also, the fact that VM developer feedback is hard to come by is
mostly due to a lack of time on their part, and a new mailing list
will not fix that.

But as I wrote, I think it is worth a try.

Thanks, Thomas

On Mon, Nov 19, 2018 at 7:48 PM JC Beyler <jcbeyler at> wrote:
> Hi all,
> I would like to start a discussion about the possible creation of the
> Atlantis Project with myself, Jean Christophe Beyler, as the Lead and the
> Serviceability group as the sponsoring group.
> In accordance with the OpenJDK guidelines [1], this project would provide a
> venue to explore and incubate monitoring and performance analysis features
> that could be integrated into the Hotspot JVM and the JVM Tool Interface.
> This includes working, evaluating, and incubating a Thread-Sanitizer
> implementation [2] for Java.
> The Google platform team has historically worked on providing new features,
> including monitoring hooks due to certain monitoring features not being
> available in a low-overhead, turned on-by-default manner. Therefore, for
> Google Java users, the platform team augmented or added mechanisms to
> assess various metrics such as but not limited to:
> - Thread Sanitizer support for Java (see JDK-8208520 [2]) (though this one
> specifically is not a low-overhead one, sorry ;-))
> - Lock contention profiles to better understand where threads are spending
> time in locks
> - Heap dumping mechanisms to improve heap dump times for large heaps
> - Efficient thread tagging to help filter profiling
> - etc.
> All of the above have added changes to the JDK in various forms and the
> Atlantis project proposes to investigate, in the open, how these changes
> could be made general enough to be pushed into the mainline, or should be
> dropped due to being too specific or could be done using other existing
> mechanisms. The project would not be a Google-only project and will have a
> mailing list to discuss and potentially accept any contribution trying to
> extend and/or enhance current monitoring systems.
> The evaluation criteria to consider a feature/improvement includes but
> would not be limited to:
>      * Performance: metrics and new hooks should not be hurting performance
> when disabled
>      * General usefulness for the community at large
>      * No working alternatives: sometimes it may be that there are new
> technologies available (ie JFR events for example) that might be leveraged
> to deprecate existing solutions
> If one or more prototypes indicate a new metric, a new monitoring system,
> or a feature offers substantial improvements, the Atlantis project would
> shepherd a JEP to integrate the change into the mainline of OpenJDK.
> The current suggested initial Reviewers and Committers would be but is most
> likely not going to be limited to:
> * Jean Christophe Beyler
> * Serguei Spitsyn
> * Chuck Rasbold
> * Liam Cushon
> What do you all think? :-)
> Thanks,
> Jc
> [1]
> [2]

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