Advances in massively parallel platforms are increasing the prospects for high performance discrete event simulation. Still the difficulty in parallel programming persists and there is increasing demand for high level...
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Advances in massively parallel platforms are increasing the prospects for high performance discrete event simulation. Still the difficulty in parallel programming persists and there is increasing demand for high level support for building discrete event models to execute on such platforms. We present a parallel DEVS-based (Discrete Event System Specification) simulation environment that can execute on distributed memory multicomputer systems with bench-marking results of a class of high resolution, large scale ecosystem models. Underlying the environment is a parallel container class library for hiding the details of message passing technology while providing high level abstractions for hierarchical, modular DEVS models. The C++ implementation working on the Thinking Machines CM-5 demonstrates that the desire for high level modeling support need not be irreconcilable with sustained high performance.
Great effort has been devoted to the design of optimized checkpointing strategies for optimistic parallel discrete event simulators. On the other hand there is less work in the direction to improve the execution mode ...
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ISBN:
(纸本)076951104X;0769511058
Great effort has been devoted to the design of optimized checkpointing strategies for optimistic parallel discrete event simulators. On the other hand there is less work in the direction to improve the execution mode of any single checkpoint operation. Specifically, checkpoint operations are typically charged to the CPU, thus leading to freezing of the simulation application while checkpointing is in progress, i.e. the execution mode of the checkpointing protocol is typically synchronous. In this paper we focus on improvements of the execution mode and present a software architecture, designed for myrinet based Network of Workstations (NOWs), to avoid application freezing during any checkpoint operation, thus moving the execution itself towards an asynchronous mode. This is done by charging checkpoint operations to a hardware component distinct from the CPU, namely a DMA engine. On the other hand, totally asynchronous checkpointing could suffer from data inconsistency whenever the content of a state buffer is accessed for further modifications while a checkpoint operation involving it is not yet completed. To avoid this, the architecture includes functionalities for resynchronization on demand. We have used these functionalities to implement an execution mode of the checkpointing protocol we refer to as semi-asynchronous. By the results of all experimental study we argue that the semi-asynchronous mode can be an effective solution to almost completely remove the delay associated with any checkpoint operation from the completion time of the simulation.
Designing fast parallel discrete event simulation systems for shared-memory parallel computers is simplified by the efficient communication operations enabled by the common memory space. The difficulties involved in d...
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ISBN:
(纸本)0769521118
Designing fast parallel discrete event simulation systems for shared-memory parallel computers is simplified by the efficient communication operations enabled by the common memory space. The difficulties involved in designing large shared-memory computers and the resulting high cost of even modest size systems has led to the proliferation of computer systems consisting of small shared-memory computers connected via low-latency message-passing interconnection networks. This paper describes how a network simulation system using a simulation kernel optimized for high performance operation on shared-memory parallel computers has been extended to operate on computers that mix shared-memory and message-passing paradigms. Results are presented showing that the system can achieve over 60 million simulated packet transmissions per second on 32 4-processor nodes. The results demonstrate the advantage of using a mixture of shared-memory and message-passing over using only message-passing in many cases.
A new conservative algorithm for both parallel and sequential simulation of networks is described. The technique is motivated by the construction of a high performance simulator for ATM networks. It permits very fast ...
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A new conservative algorithm for both parallel and sequential simulation of networks is described. The technique is motivated by the construction of a high performance simulator for ATM networks. It permits very fast execution of models of ATM systems, both sequentially and in parallel. A simple analysis of the performance of the system is made. Initial performance results from parallel and sequential implementations are presented and compared with comparable results from an optimistic TimeWarp based simulator. It is shown that the conservative simulator performs well when the 'density' of messages in the simulated system is high, a condition which is likely to hold in many interesting ATM scenarios.
parallel independent replicated simulation (PIRS) is an effective approach to speed up the simulation processes. In a PIRS, a single simulation run is executed by multiple computers in parallel. The statistical proper...
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ISBN:
(纸本)1565550277
parallel independent replicated simulation (PIRS) is an effective approach to speed up the simulation processes. In a PIRS, a single simulation run is executed by multiple computers in parallel. The statistical properties for a PIRS may be affected by the scheduling policies. For an unbiased PIRS scheduling policy, a reliable distributed computing environment is required. We consider an unbiased PIRS scheduling policy on a distributed platform such as a network of workstations. We observe that including more computing resources may degrade the performance of PIRS. Simple rules are proposed to select processors for PIRS.
A number of library-based parallel and sequential network simulators have been designed. This paper describes a library, called GloMoSim (for Global Mobile system Simulator), for parallelsimulation of wireless networ...
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ISBN:
(纸本)0818684577
A number of library-based parallel and sequential network simulators have been designed. This paper describes a library, called GloMoSim (for Global Mobile system Simulator), for parallelsimulation of wireless networks. GloMoSim has been designed to be extensible and composable: the communication protocol stack for wireless networks is divided into a set of layers, each with its own API. Models of protocols at one layer interact with those at a lower (or higher) layer only via these APIs. The modular implementation enables consistent comparison of multiple protocols at a given layer. The parallel implementation of GloMoSim can be executed using a variety of conservative synchronization protocols, which include the null message and conditional event algorithms This paper describes the GloMoSim library, addresses a number of issues relevant to its parallelization, and presents a set of experimental results on the IBM 9076 SP, a distributed memory multi-computer. These experiments use models constructed from the library modules.
The implementation of a cloning mechanism that allows for the evaluation of multiple simulated futures is presented and its performance is analyzed. A running parallel discrete event simulation is dynamically cloned a...
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ISBN:
(纸本)0818684577
The implementation of a cloning mechanism that allows for the evaluation of multiple simulated futures is presented and its performance is analyzed. A running parallel discrete event simulation is dynamically cloned at decision points to explore different execution paths concurrently. Ita this way what-if and alternative scenario analysis in gaming, tactical and strategic applications can be evaluated interactively or non-interactively. Performance results show that virtual logical processes, a new mechanism developed to avoid repeating common computations among clones improves efficiency.
This paper threats about a work that is inserted in the context of CRUX project, which aims the conception of a complete environment for parallel programming, in development in the Course of Pos-graduation in Computer...
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ISBN:
(纸本)0769518532
This paper threats about a work that is inserted in the context of CRUX project, which aims the conception of a complete environment for parallel programming, in development in the Course of Pos-graduation in Computer Science of Santa Catarina Federal University. This paper makes an evaluation of performance of several scheduling algorithms of real time found in the bibliography, about a simulation model that represents as the processing as the communication of this multi-computer. The objective was to quantify the effect of the scheduling algorithm and other factors about some metrics of selected performance, in order to verify the applicability of CRUX in real time systems.
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