Scaling Java Virtual Machine on a many-core system

In order to effectively leverage the abundant parallelism provided by large many-core enterprise servers, Java applications, libraries and the virtual machine need to be carefully architected to avoid single-thread bottlenecks. Among the challenges tackled in scaling a single Java Virtual Machine (JVM), we discuss the most rewarding ones including converting shared data objects to per-thread independent objects, applying scalable memory allocators, utilizing appropriate concurrency frameworks, parallelizing garbage collection phases and enhancing data affinity to CPUs through a NUMA aware garbage collector. In this paper, we use SPECjbb2013 to illustrate the importance of various scaling bottlenecks and demonstrate the performance gain from the discussed solutions.