Mastering increasing complexity of civil airborne equipment systems needs new architectural concepts mainly based on modular design, generic resources and multiplexed communication buses. These new architectures, such...
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ISBN:
(纸本)0818683325
Mastering increasing complexity of civil airborne equipment systems needs new architectural concepts mainly based on modular design, generic resources and multiplexed communication buses. These new architectures, such as Integrated Modular Avionics (IMA) architecture, rely on the definition of standardized hardware and software. However the development of an IMA architecture requires new tools enabling platform designer, applications developer and system integrator to describe and evaluate different implementation choices. This paper, identifies and characterizes different levels of needed models in order to catch essential information for performance evaluation of avionics applications integrated in IMA. Four model levels are proposed: application model, architectural model, execution model and allocation model. These different modeling levels allow the generation of a simulation model of avionics systems allocated on an IMA platform.
Optimistic computation methods typically save copies of objects' state information, so that they can recover from erroneous 'over-optimistic' computations. Such state saving is generally time and space con...
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Optimistic computation methods typically save copies of objects' state information, so that they can recover from erroneous 'over-optimistic' computations. Such state saving is generally time and space consuming, and can be rather complicated both to implement and to use. I show how the data structure community's theory of persistence can be used not only to analyse and explain the treatment of state in optimistic systems, but also as a simple yet general mechanism for performing the necessary state saving with minimal impact on application code. Preliminary results based on a benchmark application and an existing optimistic simulator are presented, showing that providing support for fully general object states is a realistic and practical option. In addition, I show how some existing state saving techniques - including support for shared state - can be derived, and discuss a number of ways in which the model might be extended.
An implementation of a conservative parallel simulator with deadlock avoidance is presented. Its performance when working with a realistic model of a message routing network is evaluated and contrasted against a seque...
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This paper studies the problem of load balancing for conservative parallelsimulations for execution on a multicomputer. The synchronization protocol makes use of Chandy-Misra null-messages. We propose a dynamic load ...
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This paper studies the problem of load balancing for conservative parallelsimulations for execution on a multicomputer. The synchronization protocol makes use of Chandy-Misra null-messages. We propose a dynamic load balancing algorithm which assumes no compile time knowledge about the workload parameters. It is based upon a process migration mechanism, and the notion of CPU-queue length, which indicates the workload at each processor. We examine two variations for the algorithm which we refer to as centralized and multi-level hierarchical methods, in the context of queueing network simulation of a torus. The torus was chosen because it of its many cycles aid in the formation of deadlock making it a stress test for any conservative synchronization protocols. Our experiments indicate that our dynamic load balancing schemes significantly reduce the run time of an optimized version of Chandy-Misra null message approach, and decreases by 30-40% the synchronization overhead when compared to the use of a static partitioning algorithm. Significantly, the results obtained also indicate that the multi-level scheme always outperforms both the centralized load balancing approach and the static partitioning algorithm.
The proceedings contain 11 papers. The topics discussed include: reproducible testing of distributed software with middleware virtualization and simulation;dynamic testing of flow graph based parallel applications;sch...
ISBN:
(纸本)9781605580524
The proceedings contain 11 papers. The topics discussed include: reproducible testing of distributed software with middleware virtualization and simulation;dynamic testing of flow graph based parallel applications;scheduling considerations for building dynamic verification tools for MPI;memory tagging in Charm++;support for symmetric shadow memory in multiprocessors;on-the-fly race detection in multi-threaded programs;AtomRace: data race and atomicity violation detector and healer;towards a better collaboration of static and dynamic analyses for testing concurrent programs;software development tools for multi-core/parallel programming;systematic concurrency testing using CHESS;and pitfalls in teaching development and testing of concurrent programs and how to overcome them.
The proceedings contain 22 papers. The topics discussed include: time Jails: a Hybrid Approach to Scalable Network Emulation;Adaptive Model Update Algorithms for Remote Network Emulation;toward Scalable Routing Experi...
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ISBN:
(纸本)9780769531595
The proceedings contain 22 papers. The topics discussed include: time Jails: a Hybrid Approach to Scalable Network Emulation;Adaptive Model Update Algorithms for Remote Network Emulation;toward Scalable Routing Experiments with Real-Time Network simulation;modeling and simulation of Pedestrian Behaviors;parallel and distributed Spatial simulation of Chemical Reactions;secure Referee Selection for Fair and Responsive Peer-to-Peer Gaming;stochastic Process Models for Packet/Analytic-Based Network simulations;performance Analysis of Real Traffic Carried with Encrypted Cover Flows;an Algorithm Selection Approach for simulation Systems;Symbiotic simulation Systems: an Extended Definition Motivated by Symbiosis in Biology;evaluating the Performance of Real Time Videoconferencing in Ad Hoc Networks Through Emulation;and scalable versus Accurate Physical Layer Modeling in Wireless Network simulations.
Most successful examples of parallelsimulation models were developed for parallel execution, from the beginning. A number of simulation models are designed only for sequential simulation, even in languages like PARSE...
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Most successful examples of parallelsimulation models were developed for parallel execution, from the beginning. A number of simulation models are designed only for sequential simulation, even in languages like PARSEC, that support both sequential and parallelsimulation algorithms. Converting such simulation models to a form that yields good performance with a parallel implementation can be non-trivial. We describe a case study showing this conversion process for a simulation model of replicated file systems. The details of the major steps taken in converting the simulation into a parallelsimulation are presented: correctness changes; performance changes such as communication topology simplification and lookahead specification; and modeling changes to eliminate performance bottlenecks. The details and performance improvements of each step are presented.
Efficient computer simulation of complex physical phenomena has long been challenging due to their multi-physics and multi-scale nature. In contrast to traditional time-stepped execution methods, we describe an approa...
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Cycles and knots in directed graphs are problems that can be associated with deadlocks in database and communication systems. Many algorithms to detect cycles and knots in directed graphs were proposed. Boukerche and ...
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ISBN:
(纸本)0769518532
Cycles and knots in directed graphs are problems that can be associated with deadlocks in database and communication systems. Many algorithms to detect cycles and knots in directed graphs were proposed. Boukerche and Tropper have proposed a distributed algorithm that solve the problem in a efficient away. Their algorithm has a message complexity of 2m vs. (at least) 4m for the Chandy and Misra algorithm, where in is the number of links in the graph, and requires 0 (n log n) bits of memory, where n is the number of nodes. We have implemented Boukerche and Tropper's algorithm according to the construction of processes of the CSP model. Our implementation was done. using JCSP, an implementation of CSP for Java, and the results are presented.
In this paper we consider the effect of using bus interconnection structures on the overheads present in conservative parallelsimulations of multicomputer programs. We use a modified version of the Poker Programming ...
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ISBN:
(纸本)1565550552
In this paper we consider the effect of using bus interconnection structures on the overheads present in conservative parallelsimulations of multicomputer programs. We use a modified version of the Poker Programming Environment to empirically measure the overhead in three parallel algorithms using buses. We discuss the sources of overhead and compare them with those found using point-to-point communication. Preliminary results indicate that the overheads encountered using a bus interconnection structure were not predicted by our previous results using point-to-point communications.
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