A Survey of Worst-Case Execution Time Analysis for Real-Time Java

Abstract

As real-time systems become more prevalent, there is a need to guarantee that these increasingly complex systems perform as designed. One technique involves a static analysis to place an upper bound on worst-case execution time (WCET). Other techniques aim for new architectures and algorithms that reduce the WCET. At the same time, there is a growing interest in using Java for real-time systems. Several WCET analysis prototypes for Java have been created, and more are under development.This paper provides a comprehensive survey of research that combines WCET analysis with the Java domain. We begin by explaining the importance of WCET analysis and why it is so difficult to perform adequately. We then examine the features that make Java an attractive platform for WCET analysis, as well as the new challenges it brings. Finally, we provide a survey of prior work on this subject, organized as a simple one-level taxonomy.

Performance Evaluation of Real-Time Systems

“…It is useful as java is an excellent choice for the real-time systems and in the past there are not tools for java based architectures \cite{ [7]}. To focus on Real-time Specification for Java (RTSJ), a WCET tool is required that could evaluate the performance of the Java-specific processors.…”

“…In Figure 1, the relativity of WCET with other real-time system parameters is depicted. Although a large number of metrics are currently being used to measure the performance of embedded systems, such as response time, throughput, or utilization factor of the resources etc., we choose the WCET because it is the most significant factor for the assurance and verification of the reliability of RTSs [7].…”

A desktop 3D printer in safety-critical Java

“…The execution time of individual bytecodes are independent of each others. These properties enabled building worst-case execution time (WCET) analysis tools for Java that target JOP [15,4].…”

Hardware Support for Embedded Java

“…JOP is also in use in several industrial applications [49,35]. Furthermore, the WCET friendly architecture of JOP enabled development of several WCET analysis tools for Java [19,7,23]. The WCET analysis tool WCA is part of the JOP source distribution [58].…”