A correct and useful incremental copying garbage collector

Abstract

Designing a garbage collector with real-time properties is a particularly difficult task, involving the construction of both an incremental run-time algorithm as well as methods enabling a priori reasoning about schedulability in two dimensions (time and memory usage in conjunction). In order to comply with such ambitious goals with any amount of formal rigor, a comprehensive understanding of the actual algorithm used is of course a fundamental requirement. In this paper we present a formal model of an incremental copying garbage collector, where each atomic increment is modeled as a transition between states of a heap process. Soundness of the algorithm is shown by proving that the garbage collecting heap process is weakly bisimilar to a non-collecting heap with infinite storage space. In addition, we show that our collector is both terminating and useful, in the sense that it actually recovers the unreachable parts of any given heap in a finite number of steps.

Scheduling garbage collection in real-time systems

“…We have, based on the incremental copying garbage collector presented in [18] and the real-time programming language Timber [23], developed a feasibility test for the collector. We call this test garbage collection demand analysis, which contains only clearly identified parameters of the real-time system and their corresponding effect on garbage collection time.…”

“…We will base our analysis on the incremental copying garbage collector presented in [18]. In this section we give a shortened description of the essential parts of the algorithm.…”

“…We show how an incremental copying garbage collector [18] deployed as a concurrent process in the reactive environment of the programming language Timber [23] enables us to decouple the cost of garbage collection from the feasibility of the realtime tasks. I.e., we enable any schedulability analysis for a real-time system, without the need of incorporating the cost of garbage collection into that analysis.…”

Overview of Real-Time Java Computing

“…It is not very efficient yet provides a way to implement realtime GC. This so called work-based GC is then developed by many other following researchers, such as [45] and [46] in JamaicaVM. The basic idea is kept while overhead of allocation detection and unnecessary collection is significantly reduced.…”

Using Timber in a Multi-Body Design Environment to Develop Reliable Embedded Software

“…Furthermore, the Timber semantics allows for efficient real-time garbage collection [24], thus relieving the programmer from tedious and error prone manual memory management. Altogether, object oriented abstraction, advanced type system, automatic state protection, and real-time garbage collection helps to reduce the risk of hard-to-find programming errors, such as race conditions, dead-locks, memory leakages, and pointer related errors.…”