JMTP: an architecture for exploiting concurrency in embedded Java applications with real-time considerations

Abstract

Using Java in embedded systems is plagued by problems of limited runtime performance and unpredictable runtime behavior. The Java Multi-Threaded Processor (JMTP) provides solutions to these problems. The JMTP architecture is a single chip containing an off-the-shelf general purpose processor core coupled with an array of Java Thread Processors (JTPs). Performance can be improved using this architecture by exploiting coarse-grained parallelism in the application. These performance improvements are achieved with relatively small hardware costs. Runtime predictability is improved by implementing a subset of the Java Virtual Machine (JVM) specification in the JTP and trimming away complexity without excessively restricting the Java code a JTP can handle. Moreover the JMTP architecture incorporates hardware to adaptively manage shared JMTP resources in order to satisfy JTP thread timing constraints or provide an early warning for a timing violation. This is an important feature for applications with quality-of-service demands. In addition to the hardware architecture, we describe a software framework that analyzes a Java application for expressed and implicit coarse-grained concurrent threads to execute on JTPs. This framework identifies the optimal mapping of an application to a JMTP with an arbitrary number of JTPs. We have tested this framework on a variety of applications including IDEA encryption with different JTP configurations and confirmed that the algorithm was able to obtain desired results in each case.