Memory Management for Real-Time Java: An Efficient Solution using Hardware Support*

Higuera, Teresa; Issarny, Valérie; Banâtre, Michel; Parain, Frédéric

doi:10.1023/b:time.0000009306.22263.59

Cited by 23 publications

(11 citation statements)

References 13 publications

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“…Its response time depends on the total number of reachable objects when it has to collect a non-referenced cycle. [13] propose a picoJava-II hardware implementation of an adaptation of the incremental treadmill algorithm [11]. This approach is not portable and it does not ensure predictable execution times.…”

Section: Introductionmentioning

confidence: 99%

Program Instrumentation and Run-Time Analysis of Scoped Memory in Java

Garbervetsky

Nakhli

Yovine

et al. 2005

Electronic Notes in Theoretical Computer Science

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We present a method to analyze, monitor and control dynamic memory allocation in Java. It first consists in performing pointer and escape analysis to detect memory scopes. This information is used to automatically instrument Java programs in such a way memory is allocated and freed by a region-based memory manager. Our source code instrumentation fully exploits the result of scope analysis by dynamically mapping allocation places to the region stack at runtime via a registering mechanism. Moreover, it allows executing the same transformed program with different implementations of scoped-memory managers and perform different run-time analysis without changing the transformed code. In particular, we consider a class of managers that handle variable-size regions composed of fixed-size memory blocks for which we provide analytical models for the intra-and inter-region fragmentation. These models can be used to observe and control fragmentation at run-time with negligible overhead. We describe a prototype tool that implements our approach.

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Section: Introductionmentioning

confidence: 99%

Program Instrumentation and Run-Time Analysis of Scoped Memory in Java

Garbervetsky

Nakhli

Yovine

et al. 2005

Electronic Notes in Theoretical Computer Science

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“…Note that when using a write-barrier-based GC, read barriers detecting memory access errors are not strictly necessary because read operations do not change the colour of the object, therefore they do not affect the GC coherence [13]. The restriction on critical tasks can be reduced to write barriers checks since reads do not interfere with the GC.…”

Section: The Gc and Mr Interactionmentioning

confidence: 99%

“…Hence, to detect new roots of the GC, instead of employing a technique based on the region to which the objects belong (e.g. as used by generational collectors to maintain inter-generational pointers [12]), we introduce a fourth colour indicating whether an object is outside the heap [13]. Another problem is with the critical tasks that cannot access objects within the heap.…”

Section: Related Workmentioning

confidence: 99%

Improving the memory management performance of RTSJ

Higuera-Toledano¹,

Issarny²

2005

Concurrency and Computation

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To cite this version:M. Teresa Higuera-Toledano, Valérie Issarny. Improving the memory management performance of RTSJ. SUMMARYFrom a real-time perspective, the garbage collector (GC) introduces unpredictable pauses that are not tolerated by real-time tasks. Real-time collectors eliminate this problem but introduce a high overhead. Another approach is to use memory regions (MRs) within which allocation and deallocation is customized. This facility is supported by the memory model of the Real-Time Specification for Java (RTSJ). RTSJ imposes strict access and assignment rules to avoid both the dangling inter-region references and the delays of critical tasks of the GC. A dynamic check solution can incur high overhead, which can be reduced by taking advantage of hardware features. This paper provides an in-depth analytical investigation of the overhead introduced by dynamic assignments checks in RTSJ, describing and analysing several solutions to reduce the introduced overhead.

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“…Higuera suggests in [14] the use of hardware features from picoJava [24] to speed up RTSJ memory region protection and garbage collection. A hardware assisted realtime collector is proposed by Schmidt and Nielsen [29].…”

Section: Real-timementioning

confidence: 99%

Exact roots for a real-time garbage collector

Pedersen

Schoeberl

2006

Proceedings of the 4th International Workshop on Java Technologies for Real-Time and Embedded Systems - JTRES '06

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Garbage collection is traditionally not used in real-time systems due to the unpredictable temporal behavior of current implementations of a garbage collector. However, without garbage collection the programming model is very different from standard Java. It is the opinion of the authors that garbage collection algorithms can be adapted to meet even the requirements for hard real-time systems.One important property of a real-time garbage collector is to identify only the real roots on the root scan. Misinterpreting primitive values as false root pointers can result in an unpredictable worst case memory consumption. In this paper we propose a method to add information on the stack layout to the runtime data structure in order to find the roots exactly. Furthermore, interpreting this information during the collection process is implemented to be worstcase execution time analyzable.

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Memory Management for Real-Time Java: An Efficient Solution using Hardware Support*

Cited by 23 publications

References 13 publications

Program Instrumentation and Run-Time Analysis of Scoped Memory in Java

Program Instrumentation and Run-Time Analysis of Scoped Memory in Java

Improving the memory management performance of RTSJ

Exact roots for a real-time garbage collector

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