Exploiting Multi-core Processors to Improve Time Predictability for Real-Time Java Computing

As a successful programming language, Java has extended its application from general-purpose systems to embedded, real-time systems. However, some of Java's excellent features, like automatic memory management and dynamic compilation, bring indeterminism to the execution time of real-time Java programs. In this paper, we propose several multi-core approaches to remove or at least reduce the unpredictability inside of Java Virtual Machine (JVM). Our goal is to retain high performance competitive to dynamic compilation and, at the same time, obtain better time predictability for JVM. Also, we study pre-compilation techniques to utilize second core more efficiently. Furthermore, we develop Pre-optimization on Another Core (PoAC) scheme to replace the Adaptive Optimization System (AOS) in Jikes JVM, which is very sensitive to execution time variation and impacts time predictability greatly. The experimental results indicate that our approaches are able to reach high performance while greatly reduce execution time variation of Java applications.