Tuesday, September 3, 2013

OpenJDK at Google

At the JVM Language Summit 2013Jeremy Manson gave a talk on some of the work we did around OpenJDK at Google:

  Slides: http://www.oracle.com/technetwork/java/jvmls2013manson-2013920.pdf
  Video: http://medianetwork.oracle.com/video/player/2630310903001

It covers some of my profiling and garbage collection work (on slides 29, 36 and 37):

- Making the stack trace decoding code more robust and precise and adding support for the native stack frames for the low-overhead AsyncGetCallTrace-based profiler.

- Parallel full GC for the CMS garbage collector. 2-4x pause time improvements in full GC.

- Parallel initial-mark and remark phases in the CMS garbage collector. 2-4x pause time improvements.

- Partial heap defragmentation/compaction for the CMS garbage collector. Decrease heap fragmentation-caused full GC by up to 90% (or eliminate completely.)

Give back unused RAM to the system. 20-30% RAM savings.