WCET analysis for multiprocessor based on real-time Java processor

Abstract

In this paper, we propose a solution for a worst- case execution time (WCET) analyzable Java system - a combination o f a time predictable Java processor and a method WCET analysis at Java bytecode level. The execution time o f bytecodes, the instructions of the Java virtual machine, is known cycle accurately for Java processor, which simplifies the low-level W CET analysis [1 .In hard real-time systems, the estimation o f the WCET is essential. WCET analysis is in general an undecidable problem. As concerning above, we propose some o f WCET analysis methods using control flow graph applied for high-level and low-level Java processor. Java bytecode generation has to follow stringent rules in order to pass the class file verification of the JVM. Those restrictions lead to an analysis friendly code; e.g. the stack size is known at each instruction. The control flow instructions are well defined. Branches are relative and the destination is within the same method. Detection o f basic blocks in Java bytecode and construction o f the control flow graph (CFG) is thus straight forward.