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