Asynchronous event handling in the real-time specification for Java

Kim, MinSeong; Wellings, Andy

doi:10.1145/1288940.1288942

Cited by 8 publications

(13 citation statements)

References 5 publications

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“…The presence of these limitations in java, which directly affects the predictability of temporal execution of Java applications, can be summarized in the following points [6][7][8]: � Unpredictable latencies caused by the garbage collector Garbage collection (GC) is considered the primary source of unpredictability in Java applications. All GC algorithms used in standard JVMs involve a stop-the world pause, in which threads are stopped so that the garbage collector can run without interference.…”

Section: Java's Weaknesses For Real-time Systemsmentioning

confidence: 99%

A review of the current status of the Java programming on embedded real-time systems

Alhussian

Zakaria

Hussin

et al. 2012

2012 International Conference on Computer &Amp; Information Science (ICCIS)

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As embedded and real-time systems are becoming more and more Internet-enabled with a plethora of processors, operating systems, and peripheral device types; the line between general purpose programming and low-level specialized programming is now blurring and systems that used to be specialized and low-level become larger and more complex. The Java environment, with its platform neutrality, simplified obj ect model, strong notions of safety and security, as well as multithreading support, provides many advantages for the new generation of embedded and real-time systems. However, the large size, nondeterministic behavior, and poor performance have hampered the acceptance of Java in the real-time and embedded systems domain. This paper reviews the current state of Java in the new generation of embedded and real-time systems domain.

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Section: Java's Weaknesses For Real-time Systemsmentioning

confidence: 99%

A review of the current status of the Java programming on embedded real-time systems

Alhussian

Zakaria

Hussin

et al. 2012

2012 International Conference on Computer &Amp; Information Science (ICCIS)

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“…In [7] various AEH models used in some popular RTSJ implementations are examined and their respective pros and cons are discussed. Here we briefly review that paper's results in order to illustrate the various implementation approaches that can be adopted.…”

Section: Aeh Models In Rtsj Implementationsmentioning

confidence: 99%

Refactoring Asynchronous Event Handling in the Real-Time Specification for Java

Kim

Wellings

2009

2009 21st Euromicro Conference on Real-Time Systems

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The primary goal for asynchronous event handling (AEH) in the Real-Time Specification for Java (RTSJ) is to have a lightweight concurrency mechanism. However the RTSJ neither provides a well-defined guideline on how to implement AEH nor requires the documentation of the AEH model used in the implementation. Also the AEH API in the RTSJ are criticised as lacking in configurability as they do not provide any means for programmers to have fine control over the AEH facilities, such as the mapping between real-time threads and handlers. For these reasons, it needs the refactoring of its application programming interface (API) to give programmers more configurability. This paper, therefore, proposes a set of AEH related classes and interfaces to enable flexible configurability over AEH components. We have implemented the refactored configurable AEH API using the new specifications on an existing RTSJ implementation and this paper shows that it allows more configurability for programmers than the current AEH API in the RTSJ does. Consequently programmers are able to specifically tailor the AEH subsystem to fit their applications' particular needs.

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“…This works fine unless handlers block, in which case unbounded priority inversion will occur. To avoid this, it is necessary to dynamically create a new server (or take one from a pool Table 1: Numbers of Severs required as the number of handlers increases in Java RTS [7].…”

Section: Jamaica From Aicas [5]mentioning

confidence: 99%

“…The run-time or event firing thread will notify a follower directly). This AEH algorithm used in jRate is constructed in a formal model and it was simulated and verified using a model checking tool, UPPAAL [7]. The results from the paper, which are shown in Table 1, demonstrates that although it works fine with no deadlocks, the algorithm essentially requires the same number of servers as the number of the simultaneously released handlers in the system at all times.…”

Section: Jrate From Washington University [2]mentioning

confidence: 99%

“…The Real-Time Specification for Java (RTSJ) [1] has made several modifications to the Java specification in order to make true real-time processing possible [7]. The primary goal of the RTSJ is to provide a platform, a Java execution environment and application program interface (API), that lets programmers correctly reason about the temporal behaviour of executing software.…”

Section: Introductionmentioning

confidence: 99%

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An efficient and predictable implementation of asynchronous event handling in the RTSJ

Kim

Wellings

2008

Proceedings of the 6th International Workshop on Java Technologies for Real-Time and Embedded Systems

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Asynchronously happenings are crucial in real-time systems. Many real-time applications are designed with some periodic execution logics and a significant number of asynchronous events. Evidently it would not be a good performance choice if each event handler is constructed with its own thread of control. However it is generally unclear how to map threads to handlers effectively in the Real-Time Specification for Java (RTSJ). This paper, therefore, summarizes the Asynchronous Event Handler (AEH) techniques used in several popular RTSJ implementations and proposes two efficient and predictable implementations of AEH for the RTSJ. Currently the support for non-blocking handlers in the RTSJ is criticised as lacking in configurability [12] as the AEH of the RTSJ takes no advantage of non-blocking handlers. In the proposed models, non-blocking handlers are serviced by realtime threads that assume handlers may not block and blocking handlers are dealt by real-time threads that assume handlers may block. In this way it is possible to assign a thread to handlers at the right time in the right place while maintaining the least possible number of threads overall. We have implemented the proposed models on an existing RTSJ implementation, jRate. With the implementations of the models we ran a set of performance tests that measure their respective dispatch and multiple handlers completion latency. The results from the tests are promising and indicates that the proposed models have fewer threads on average with better performance than other approaches.

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Asynchronous event handling in the real-time specification for Java

Cited by 8 publications

References 5 publications

A review of the current status of the Java programming on embedded real-time systems

A review of the current status of the Java programming on embedded real-time systems

Refactoring Asynchronous Event Handling in the Real-Time Specification for Java

An efficient and predictable implementation of asynchronous event handling in the RTSJ

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