Re: Call For Discussion: New Project: Atlantis

[Jonathan Lu]

Hi JC,

Personally, I like this idea.

And I'm especially interested in the heap dumping part.
It costs a lot to create, transfer, and analyze huge heap dump files for my applications.
Maybe some fundamental changes can be explored in this project, I guess,
 such as making an enhanced format of heap dump file :)

Thank you
Jonathan


------------------------------------------------------------------
From:JC Beyler <jcbeyler at google.com>
Send Time:2018年11月20日(星期二) 02:48
To:discuss <discuss at openjdk.java.net>
Cc:serguei.spitsyn <serguei.spitsyn at oracle.com>
Subject:Call For Discussion: New Project: Atlantis

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] http://openjdk.java.net/projects/#new-project
[2] https://bugs.openjdk.java.net/browse/JDK-8208520