Wednesday Aug 07, 2013

Garbage First Garbage Collector Tuning

A new article, now up on otn/java, titled “Garbage First Garbage Collector Tuning,”
by Monica Beckwith, Principal Member of Technical Staff at Oracle, and performance lead for the Java HotSpot VM's Garbage First Garbage Collector (G1 GC), shows how to adapt and tune the G1 GC for evaluation, analysis, and performance.

As Beckwith explains, the Garbage First Garbage Collector is the low-pause, server-style generational garbage collector for Java HotSpot VM. It uses both concurrent and parallel phases to achieve its target pause time and maintain good throughput. A garbage collector is a memory management tool. When G1 GC determines that a garbage collection is necessary, it first collects the regions with the least live data – known as garbage first.

Beckwith describes the collection phases and marking cycles, lists default tuning devices, offers recommendations about how to fine tune and evaluate garbage collection, and shows how to respond to overflow and exhausted log messages.

She concludes her article as follows:

“G1 GC is a regionalized, parallel-concurrent, incremental garbage collector that provides more predictable pauses compared to other HotSpot GCs. The incremental nature lets G1 GC work with larger heaps and still provide reasonable worst-case response times. The adaptive nature of G1 GC just needs a maximum soft-real time pause-time goal along-with the desired maximum and minimum size for the Java heap on the JVM command line.”

Check it out here.

Tuesday Jul 24, 2012

The JVM Language Summit - 2012

A new article, now up on otn/java, provides information about the upcoming 2012 JVM Language Summit, scheduled for July 30–August 1, 2012 on the Oracle campus in Santa Clara. The Summit brings together top language designers, compiler writers, tool builders, runtime engineers, and VM architects, from around the world for an open technical collaboration.

Summit organizer Brian Goetz of Oracle remarks: "We've been running the JVM Language Summit for the past five years. The attendees at the Summit are the people who are making languages on the JVM happen—there are typically architect-level representatives from many JVM language communities including JRuby, Jython, Scala, Groovy, and Clojure. This is a tremendous opportunity for the community to influence the future direction of the JVM and for us to learn more about how the JVM is being used, where it shines, and where it falls short."

The schedule is equally divided between traditional presentations, most of which are limited to 40 minutes, and informal workshops, which consist of small facilitated discussion groups among self-selected participants to enable deeper dives into the subject matter. There will also be impromptu lightning talks.

Learn more here.


Friday Aug 05, 2011

A Fresh Look at Embedded with Greg Bollella, Chief Architect, Embedded Java

In a new interview on OTN, Greg Bollella explores the rich potential of Java in the embedded space. He defines the embedded space as, “any device that includes a general-purpose processor and OS, plus a software execution environment, but which would not be identified as a computer by a layperson.” He points out that, increasingly, with cars, stereos, printers, cameras, TVs and DVDs, traffic signals controllers, planes, washing machines, refrigerators, and much more, it’s the software and not the hardware that matters the most.

Bollella believes that developers have only scratched the surface when it comes to Java for embedded and that Java’s multi-core support, security, multi-platform support, and networking strengths are of great value for embedded developers.

As he states in the interview, “To create new projects we want to create a VM and library set and some tools to entice the embedded developer to use Java for their next project. So that’s my mission.”

To integrate embedded devices into a networked world is no small task. From the interview:

“You need a fairly complex software architecture to integrate these devices into the networked world. Doing that from scratch is pretty tough. Oracle can provide the client side piece, the piece in the device, as well as the backend servers and the middleware. That, combined with a very small amount of engineering from the device manufacturers, can enable them to collect operational data on the device, time-stamp it, save it to the local data base, and have that data be automatically synced with the backend database and thus available for analysis and provision of new services for the device owner.”

Read the interview here.

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