Cost Analysis for Real-time Java Scoped-memory Areas

Delvin Defoe, Rob LeGrand, Ron Cytron

Java has recently joined C and C++ as a development platform for real-time and embedded applications. Java’s garbage collection, while generally a useful feature, can be problematic for these applications: garbage collection occurs at unpredictable times and its latency is typically unbounded. This can compromise necessary real-time guarantees. To overcome these limitations, the Real-Time for Java Expert Group (RTJEG) proposed the Real-Time Specification for Java (RTSJ), which introduced new memory models and new threads to utilize those models. One such memory model uses scoped-memory areas, which work best in the context of a NoHeapRealtimeThread (NHRT). Although much work has been done with scoped-memory areas and NHRTs, there is no system-independent analysis of their costs. In this article we present an asymptotic analysis for RTSJ scoped-memory areas and NHRTs.

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