parallel discrete event simulation (PDES) of models with fine-grained computation remains a challenging problem. We explore the usage of POSE, our parallel Object-oriented simulation Environment, for application perfo...
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ISBN:
(纸本)0769523838
parallel discrete event simulation (PDES) of models with fine-grained computation remains a challenging problem. We explore the usage of POSE, our parallel Object-oriented simulation Environment, for application performance prediction on large parallel machines such as BlueGene. This study involves the simulation of communication at the packet level through a detailed network model. This presents an extremely fine-grained simulation: events correspond to the transmission and receipt of packets. Computation is minimal, communication dominates, and strong dependencies between events result in a low degree of parallelism. There is limited look-ahead capability since the outcome of many events is determined by the application whose performance the simulation is predicting. Thus conservative synchronization approaches are challenging for this type of problem. We present recent experiences and performance results for our network simulator and illustrate the utility of our simulator through prediction and validation studies for a molecular dynamics application.(1)
In this paper we discuss and compare three different causality inconsistency tracking mechanisms in support Of preemptive rollback in optimistic parallelsimulation on myrinet clusters. These mechanisms exhibit differ...
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ISBN:
(纸本)0769518532
In this paper we discuss and compare three different causality inconsistency tracking mechanisms in support Of preemptive rollback in optimistic parallelsimulation on myrinet clusters. These mechanisms exhibit different communication/processing overhead and also different effectiveness in revealing causality inconsistency of the currently executed, simulation event. By the results of an empirical study on a classical simulation benchmark we have found some trade-offs between these mechanisms, pointing out indications of application contexts for which each mechanism is expected to be well tailored.
We examine a parallel processing method for simulations of large-scale networks with a hybrid traffic representation combining both a time-stepped fluid model and a discrete-event packet-oriented model. This method be...
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ISBN:
(纸本)9780769528984
We examine a parallel processing method for simulations of large-scale networks with a hybrid traffic representation combining both a time-stepped fluid model and a discrete-event packet-oriented model. This method benefits from the observation that the time it takes to propagate-fluid characteristics along the path taken by the traffic flows has a lower bound equal to the minimum link delay as manifested by the governing ordinary differential equations (ODEs). A better lookahead can thus be used to allow parallelsimulation of the hybrid model to run without more synchronization overhead than the corresponding discrete-event packet-oriented model. We derive an analytical model comparing the fluid model and the packet-oriented model both for sequential and parallelsimulations. We demonstrate the benefit of the parallel hybrid model through a series of simulation experiments of a large-scale network consisting of over 170,000 hosts and 1.6 million traffic flows on a small parallel cluster.
This paper presents the results of an experimental study to evaluate the effectiveness of multiple synchronization protocols and partitioning algorithms in reducing the execution time of switch-level models of VLSI ci...
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This paper presents the results of an experimental study to evaluate the effectiveness of multiple synchronization protocols and partitioning algorithms in reducing the execution time of switch-level models of VLSI circuits. Specific contributions of this paper include: (i) parallelizing an existing switch-level simulator such that the model can be executed using conservative and optimistic simulation protocols with minor changes, (ii) evaluating effectiveness of several partitioning algorithms for parallelsimulation, and (iii) demonstrating speedups with both consecutive and optimistic simulation protocols for seven circuits, ranging in size from 3 K transistors to about 87 K transistors.
Lookahead is a critical factor in conservative parallelsimulation. Greater lookahead usually brings better performance. However, in the simulation of computer networks, lookahead is usually determined by the minimal ...
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ISBN:
(纸本)9780769531595
Lookahead is a critical factor in conservative parallelsimulation. Greater lookahead usually brings better performance. However, in the simulation of computer networks, lookahead is usually determined by the minimal delay of the border links between any two subnets that simulated by different sequential logical processes (LPs), which is too small to get good performance. Traditionally, the lookahead exploitation usually only reflects the parallelism among LPs, which possibly wastes the potential parallelism inside each LP, especially, in the case that each LP simulates thousands of entities. Here we present a simple method called micro-synchronization to exploit the parallelism inside each LP. Different from the previous work, such as lookahead accumulation and local time warp, we keep the traditional usage of lookahead among LPs unchanged, and however, we impose the relaxed sequential event scheduling inside each LP, which can indirectly improve the lookahead We also present a state causality model to prove the correctness of our method, which means that there is no risk in the relaxed sequential execution. Finally, the experiment evaluates our method and shows that it can improve the performance of conservative parallelsimulation of computer networks to some extent.
作者：
Rosato, VPucello, NENEA
HPCN Project Ente Nuove Tecnol Energia & Ambiente I-00100 Rome Italy
A code for Me simulation of X-ray diffraction pattern of a powder has been implemented on a massively parallel SIMD platform developed in the frame of the PQE2000 Project. The code allows the evaluation of the diffrac...
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ISBN:
(纸本)0769500595
A code for Me simulation of X-ray diffraction pattern of a powder has been implemented on a massively parallel SIMD platform developed in the frame of the PQE2000 Project. The code allows the evaluation of the diffraction pattern of atomic-scale models of both perfectly ordered and disordered structures. The code has been wed to investigate the structures resulting from the non-equilibrium alloying process of an immiscible metallic couple (Ag-Cu).
With the emerging of broadband networks based on ATM technology, performance evaluation tools that allow the study of large systems are desperately needed. In this article we present our experiments in distributed sim...
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ISBN:
(纸本)0818684577
With the emerging of broadband networks based on ATM technology, performance evaluation tools that allow the study of large systems are desperately needed. In this article we present our experiments in distributedsimulation of large and complex ATM network models with a conservative simulator. The goal here was not to achieve the maximum speedup with well-shaped topologies but rather to see what speedup can be obtained with a realistic model on a "state-of-the art" parallel computer. A network model with 78 switches is simulated on a Gray T3E using 3 different traffic loads. The performance results show that good speedups can be achieved but also highlight partitioning problems and bottlenecks in the simulation model that can seriously limit the speedup of realistic model simulations.
The implementation of a distributed digital logic simulation algorithm on a network of workstations is presented. The simulation of digital circuits is done using a demand driven approach. The simulation is performed ...
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