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.
distributed Virtual Environments (DVEs) such as online games, military simulations or collaborative design are currently very popular. To support large-scale DVEs, an architecture with multiple, geographically distrib...
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ISBN:
(纸本)9780769525877
distributed Virtual Environments (DVEs) such as online games, military simulations or collaborative design are currently very popular. To support large-scale DVEs, an architecture with multiple, geographically distributed servers is usually employed, and the virtual world is partitioned into multiple zones for load distribution. The client assignment problem arises when assigning the participating clients to the servers. Current approaches usually assign clients to servers based on a resource-driven approach, i.e. the only concern is not to overload the servers. This approach may degrade the interactivity of DVEs if the network delay from a client to its assigned server is large. In this paper, we formulate the client assignment problem, and propose three new algorithms to assign clients to servers in a more efficient way. The proposed algorithms are based on the greedy heuristics developed for the well-known Terminal Assignment problem. From extensive simulation studies with realistic settings, we find that even under heterogeneous environments such as the Internet where accurate input data for the assignment algorithms are usually impractical to obtain, some of the proposed algorithms are still beneficial to the performances of DVEs.
parallel Discrete Event simulation (PDES) allows to speed up the execution of a simulation by distributing the simulation's workload between multiple processors. The mapping of the simulation entities over the pro...
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ISBN:
(纸本)9789549641523
parallel Discrete Event simulation (PDES) allows to speed up the execution of a simulation by distributing the simulation's workload between multiple processors. The mapping of the simulation entities over the processors is very important with regard to the efficiency of the overall process of simulation. This paper presents an approach for automation of the process of mapping over distributed environment (network of workstations) for optimistic simulation based on the synchronization protocol Time Warp.
This paper introduces a radically different approach to parallelsimulation for gate level design, aimed at completely eliminating the communication and synchronization overhead between simulators. It is based on a ne...
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It is essential to evaluate the performance of newly developed distributed software and network protocols. Network emulation enables reproducible evaluation of unmodified real implementations. Software built for distr...
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ISBN:
(纸本)9780769531595
It is essential to evaluate the performance of newly developed distributed software and network protocols. Network emulation enables reproducible evaluation of unmodified real implementations. Software built for distributed systems, such as a large scale peer-to-peer system, requires evaluation scenarios with thousands of communicating nodes. Two approaches for scaling network emulation to such scenario sizes have been proposed in the literature: node virtualization and time virtualization. Node virtualization allows maximizing the utilization of standard hardware used for emulation experiments. Time virtualization enables trading experiment duration for virtually increased resources of the hardware. It stands to reason that a combination of those two approaches may increase scalability even further. However, in existing combinations, either node virtualization implies relatively high overhead or time virtualization requires modifications of the test subject implementation. In this paper, we present a novel hybrid approach called Time Virtualized Emulation Environment (TVEE). It integrates node virtualization with low overhead and time virtualization, which is transparent to the execution of test subjects. We introduce virtual time based on epochs to enable better dynamic hardware utilization during long lasting experiments. Additionally, a mechanism similar to soft timers ensures an accurate reproduction of network properties in the time virtualized emulation. Our evaluations show the accuracy and scalability of time virtualized network emulation. Comparing TCP throughput, TVEE outperforms other approaches using an event based virtual time by an order of magnitude.
parallel discrete event simulation (PDES) is a basic approach for evaluation of complex systems. A PDES attempts to speed up the execution of a simulation by distributing the simulation's workload between multiple...
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ISBN:
(纸本)9789549641523
parallel discrete event simulation (PDES) is a basic approach for evaluation of complex systems. A PDES attempts to speed up the execution of a simulation by distributing the simulation's workload between multiple processors. A network of workstations is a widely available platform for PDES. The present article provides a comparative analysis of operational distributedsimulation models based on the Time Warp algorithm. An operational model allowing for reduction of the simulation costs has been proposed based on an experimental evaluation.
P2P Grids are Grids organized into P2P networks where participant exchange computing time so as to complete computational tasks. Evaluating the performance of scheduling algorithms enables one to deploy those that are...
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ISBN:
(纸本)9781605580524
P2P Grids are Grids organized into P2P networks where participant exchange computing time so as to complete computational tasks. Evaluating the performance of scheduling algorithms enables one to deploy those that are efficient. Performance is often evaluated experimentally or through simulation because these algorithms (typically heuristics) are too complex to model analytically. Testing the implementation of P2P Grid middleware before it is deployed is also important: Reproducing configurations or conditions that lead to unexpected outcomes is thus valuable. A P2P Grid environment exhibits multiple sources of failure and is typically dynamic and uncontrollable. Reproducing even basic behavior of Grid nodes in a controllable and repeatable manner is thus exceedingly difficult. Such lack of control over the environment is a major challenge in the software engineering of P2P Grid middleware [7]. Simulators have been proposed to evaluate the performance of scheduling algorithms, but are often limited in scope, reusability and accuracy, i.e. they rely on simplified models. We introduce a software engineering pattern - that we call code once, deploy twice - to both reduce the distance between simulated and implemented algorithms and reproduce, at will, Grid configurations and environments: A simulator implementation of a Grid architecture is built by virtualizing its middleware implementation. An immediate benefit is that most of the code can be reused between both implementations;only communications between Grid nodes, multithreading within Grid nodes and actual task execution are coded differently. As a derived benefit, most of the code of the middleware can be tested within the controlled environment of the simulator, before it is deployed as-is. Another benefit is high simulation accuracy. We describe the implementation of a P2P Grid following the code once, deploy twice pattern, that we believe is also relevant to other Grid types (certainly Volunteer Grids [5, 4]
The Hierarchically Tiled Array (HTA) is a data type that facilitates the definition and manipulation of arrays partitioned into tiles. The data type allows to exploit those tiles to attain both locality and parallelis...
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ISBN:
(纸本)9783540705499
The Hierarchically Tiled Array (HTA) is a data type that facilitates the definition and manipulation of arrays partitioned into tiles. The data type allows to exploit those tiles to attain both locality and parallelism. parallel programs written with HTAs are based in data parallelism, and provide the programmer with a single-threaded view of the execution. In our experience, HTAs help to develop parallel codes in a. much more productive way than other parallel prograrmning approaches. While we have worked extensively with HTAs in distributed mernor,y environments, only recently have we began to consider their adaption to shared memory environments such as those found in rriulticore systems. In this paper we review the design issues, opportunities and challenges that this migration raises.
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