Object layout optimization in the JVM based on affinity

Abstract

Improving spatial locality has a great impact on improving cache performance by reducing the number of cache misses. Object model optimization is one way to improve the locality of references inside particular objects. This paper extends the object layout optimization study by focusing on the internal layout of Java objects in applications running on the Java Virtual Machine (JVM). In this research, the IBM JVM is modified to be able to organize fields inside Java objects based on their access frequency and access order. Our results show reductions in the number of cache misses in the 20% range and an almost 40% speed up in some benchmarks.