Strange Loop

Shenandoah: An open source pauseless GC for OpenJDK.

Back in the lisp machine days hitting a GC pause meant it was time to go get a cup of coffee. Java Virtual Machines (JVMs) do better by using parallel (multiple threads working together) and concurrent (gc threads working while the mutator is running) techniques however pauses still cost time and in the case of online transactions money. This talk will discuss a new GC algorithm being developed at Red Hat for OpenJDK. Shenandoah is the first open-source OpenJDK GC algorithm that does marking and evacuation concurrently with running Java threads. This allows us to keep our pause times under 10ms even for heaps of 100+GBs.

Christine Flood

Red Hat

Christine H. Flood has been designing and implementing programming languages for over 20 years. Starting with Lisp machines, dabbling with implicitly parallel languages like ID and Fortress and diving into the bits of Java Virtual Machine implementations. She's written multiple papers on GC algorithms and is delighted to be taking them to the next level for OpenJDK.