WCET analysis for a Java processor

Abstract

In this paper we propose a solution for a worst-case execution time (WCET) analyzable Java system: a combination of a time predictable Java processor and a tool that performs WCET analysis of Java bytecode. We present a Java processor, called JOP, designed for time-predictable execution of real-time tasks. JOP is an implementation of the Java virtual machine (JVM) in hardware. The execution time of bytecodes, the instructions of the JVM, is known cycle accurate for JOP. Therefore, JOP simplifies the low-level WCET analysis. A method cache, that fills whole Java methods into the cache, is analyzable with respect to the WCET. The WCET analysis tool is based on integer linear programming. The tool performs the low-level analysis at the bytecode level and integrates the method cache analysis for a two block cache.