Instruction Set Enhancements for High-Performance Multicore Execution on the REALJava Platform

This paper presents instruction set enhancements for improving the performance of multicore execution of Java bytecode on the REALJava virtual machine. The instruction set is simplified by removing redundant bytecodes, and certain instruction sequences are transformed into so-called superinstructions in order to reduce the amount of interrupt requests produced by the REALJava co-processors and the amount of communication required between the host CPU and the co-processors. The technique greatly improves the performance of multi-threaded code and, to a lesser extent, single threaded code. The technique is applied as a preprocessing step during class loading and therefore has no negative impact on performance during actual execution.