An Investigation into Automatic Dynamic Memory Management Strategies using Compacting Collection

This paper describes the design, implementation and performance characteristics of several compacting collectors in the Java Memorymanagement Toolkit (JMTk). Compacting collectors are an important class of collectors used in several production runtimes, including Microsoft’s Common Language Runtime and IBM’s Java Runtime Environment. The development of a strategy using compaction makes an important contribution to JMTk, and provides a platform where side-by-side comparisons between compacting collectors and other important classes of collector can be made. This work should be considered but a first step into the investigation of this class of collectors. It is anticipated that through broadening the set of operations supported by JMTk and Jikes RVM that this work will also allow new classes of collectors to be implemented and compared. Although there was found to be a high cost in performing a compacting collection, it was found to be provide reduced memory fragmentation.