Real-time garbage collection is essential if object-oriented languages (in particular, Java) are to become predictable enough for real-time embedded systems. Although techniques for hard real-time garbage collection e...
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One important role for Ada programming is to aid engineering of concurrent and distributed software. In a concurrent and distributed environment, objects may execute concurrently and need to be synchronized to serve a...
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Both Ada and Java support concurrentprogramming, but through quite different approaches. Ada has built-in tasking features with concurrency semantics, independent of the language's OOP model, whereas Java's t...
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This paper presents features of an objectbasedconcurrent language called Actel. In particular, it introduces the mechanisms of inter and intra-object concurrency and synchronisation. inter object concurrency is achi...
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ISBN:
(纸本)0818680431
This paper presents features of an objectbasedconcurrent language called Actel. In particular, it introduces the mechanisms of inter and intra-object concurrency and synchronisation. inter object concurrency is achieved with conventional message passing (value and priority) and also with a new mode of message passing called the semi-reference. Intra-object concurrency may be achieved with parallel functions, parallel compound statements, simultaneous compound statement, and multiple methods invocation. Synchronisation may be achieved with simple, multiple, or overloaded future variables. An example illustrates various Actel features.
This paper describes the design and implementation of a garbage collection scheme on large-scale distributed-memory computers and reports various experimental results. The collector is based on the conservative GC lib...
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This paper describes the design and implementation of a garbage collection scheme on large-scale distributed-memory computers and reports various experimental results. The collector is based on the conservative GC library by Boehm & Weiser. Each processor traces local pointers using the GC library while traversing remote pointers by exchanging 'mark messages' between processors. It exhibits a promising performance - in the most space-intensive settings we tested, the total collection overhead ranges from 5% up to 15% of the application running time (excluding idle time). We not only examine basic performance figures such as the total overhead or latency of a global collection, but also demonstrate how local collection scheduling strategies affect application performance. In our collector, a local collection is scheduled either independently or synchronously. Experimental results show that the benefit of independent local collections has been overstated in the literature. Independent local collections slowed down application performance to 40%, by increasing the average communication latency. Synchronized local collections exhibit much more robust performance characteristics than independent local collections and the overhead for global synchronization is not significant. Furthermore, we show that an adaptive collection scheduler can select the appropriate local collection strategy based on the application's behavior. The collector has been used in a concurrentobject-oriented language ABCL/f and the performance is measured on a large-scale parallel computer (256 processors) using four non-trivial applications written in ABCL/f.
This paper describes the design and implementation of a garbage collection scheme on large-scale distributed-memory computers and reports various experimental results. The collector is based on the conservative GC lib...
ISBN:
(纸本)9780897919067
This paper describes the design and implementation of a garbage collection scheme on large-scale distributed-memory computers and reports various experimental results. The collector is based on the conservative GC library by Boehm & Weiser. Each processor traces local pointers using the GC library while traversing remote pointers by exchanging "mark messages" between processors. It exhibits a promising performance---in the most space-intensive settings we tested, the total collection overhead ranges from 5% up to 15% of the application running time (excluding idle time). We not only examine basic performance figures such as the total overhead or latency of a global collection, but also demonstrate how local collection scheduling strategies affect application performance. In our collector, a local collection is scheduled either independently or synchronously. Experimental results show that the benefit of independent local collections has been overstated in the literature. Independent local collections slowed down application performance to 40%, by increasing the average communication latency. Synchronized local collections exhibit much more robust performance characteristics than independent local collections and the overhead for global synchronization is not significant. Furthermore, we show that an adaptive collection scheduler can select the appropriate local collection strategy based on the application's behavior. The collector has been used in a concurrentobject-oriented language ABCL/f and the performance is measured on a large-scale parallel computer (256 processors) using four non-trivial applications written in ABCL/f.
We present a graphical environment for parallel object-oriented programming. It provides visual tools to develop and debug object-oriented programs as well as parallel or concurrent systems. This environment was deriv...
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ISBN:
(纸本)9780897917889
We present a graphical environment for parallel object-oriented programming. It provides visual tools to develop and debug object-oriented programs as well as parallel or concurrent systems. This environment was derived from a structural operational semantics of an extension of the Eiffel language, Eiffel/ /. object-related features of the language (inheritance, polymorphism) are formalized using a big-step semantics, while the interleaving model of concurrency is expressed with small-step semantics. Without user instrumentation, the interactive environment proposes features such as step-by-step animated executions, graphical visualization of object and process topology, futures and pending requests, control of interleaving, deadlock detection.
This report presents a summary of the recently concluded workshop which was organized to stimulate and focus research on design patterns for concurrent, parallel, and distributed (CPD) object-oriented systems. Partici...
ISBN:
(纸本)0897917219
This report presents a summary of the recently concluded workshop which was organized to stimulate and focus research on design patterns for concurrent, parallel, and distributed (CPD) object-oriented systems. Participants examined design patterns that capture the static and dynamic structures of successful solutions to problems known to arise when building CPD systems. The goal of the workshop was to document and collect common design patterns to facilitate the practical construction of CPD systems.
The workshop on object-Oriented Real-Time Systems has been conduced each year at OOPSLA since 1988 with a variety of formats. In this year's workshop, participants submitted position papers on a broad range of sub...
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ISBN:
(纸本)0897917219
The workshop on object-Oriented Real-Time Systems has been conduced each year at OOPSLA since 1988 with a variety of formats. In this year's workshop, participants submitted position papers on a broad range of subjects, but were all asked to show the relevance of their work to three critical issues in OO real-time systems: dealing with time constraints;the roles of reactive versus scheduled behavior;and appropriate models of concurrent behavior. All position papers were presented and discussed during the workshop, followed by a round-table discussion of the state of the art regarding the three focus issues.
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