Shenandoah: An open-source concurrent compacting garbage collector for OpenJDK

Shenandoah is an open-source region-based low-pause parallel and concurrent garbage collection (GC) algorithm targeting large heap applications. Snapshot At the Beginning Concurrent Marking and Brooks-style indirection pointer concurrent compaction enable significantly shorter GC pauses with durations that are independent of the application's live data size. Our implementation of Shenandoah in OpenJDK allows us to do comparison testing with mature production quality GC algorithms. Modern machines have more memory and more processors than ever before. Service Level Agreement (SLA) applications guarantee response times of 10-500ms. In order to meet the lower end of that goal we need garbage collection algorithms which are efficient enough to allow programs to run in the available memory, but also optimized to never interrupt the running program for more than a handful of milliseconds. Shenandoah is an open-source low-pause time collector for OpenJDK designed to move closer to those goals.