一种实时Java处理器‘区域’内存实现模型

Framework of Scoped Memory in RTSJ-Compliant Java Processor

Java实时规范(RTSJ)提出的‘区域’内存(ScopedMemory)既避免了垃圾回收对系统实时性的影响,又能充分利用内存空间,引起了众多研究人员的重视.本文讨论了‘区域’内存的实现及影响最坏情况下执行时间(WCET)的因素,并提出一种针对嵌入式实时Java处理器的‘区域’内存实现模型.该模型中非实时处理在字节码被执行之前完成,消除了运行时管理‘区域’内存对WCET的影响,在简化处理器实现的同时保证了运行时WCET的可预测性.

Scoped memory is a novel mechanism for Java in real-time applications, and is currently provided in the Real-Time Specification for Java （RTSJ）. It can employ memory efficiently without being interfered by the Garbage Collector. Through analyzing the methods to implement scoped memory and those factors influencing the Worst Case Execution Time （WCET） of the scoped memory, this paper proposes a framework to implement the scoped memory in the RTSJ-compliant Java processor. In this framework, all non real-time jobs are processed before execution. Hence, the implementation using this framework is straightforward and its WCET is more predictable.