The application of parallel and distributedsimulation techniques is often limited by the amount of parallelism available in the model. This holds true for large-scale cell-biological simulations, afield that has emer...
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ISBN:
(纸本)9780769531595
The application of parallel and distributedsimulation techniques is often limited by the amount of parallelism available in the model. This holds true for large-scale cell-biological simulations, afield that has emerged as data and knowledge concerning these systems increases and biologists call for tools to guide wet-lab experimentation. A promising approach to exploit parallelism in this domain is the integration of spatial aspects, which are often crucial to a model's validity. We describe an optimistic, parallel and distributed variant of the Next-Subvolume Method (NSM), a method that augments the well-known Gillespie Stochastic simulation Algorithm (SSA) with spatial features. We discuss requirements imposed by this application on a parallel discrete event simulation engine to achieve efficient execution. First results of combining NSM and the grid-inspired simulation system AURORA are shown.
In this paper, we present two new methods to simulate Petri Nets: a data parallelsimulation and a distributedsimulation. Both simulations use an equational representation of the net in the so called (min, +) algebra...
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In this paper, we present two new methods to simulate Petri Nets: a data parallelsimulation and a distributedsimulation. Both simulations use an equational representation of the net in the so called (min, +) algebra. The data parallelsimulation is based on the use of matrix representation of these equations, and the distributedsimulation on the decomposition of a Petri Net into marked graph components.
The simulation of wide area computer networks is one area where the benefits of parallelsimulation have been clearly demonstrated Here we present a description of a system that uses a parallel discrete event simulato...
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ISBN:
(纸本)0769506771
The simulation of wide area computer networks is one area where the benefits of parallelsimulation have been clearly demonstrated Here we present a description of a system that uses a parallel discrete event simulator to act as a high speed network emulator With this, real Internet Protocol (IP) traffic generated by application programs running on user workstations can interact with modelled traffic in the emulator thus providing a controlled test environment for distributed applications. The network emulator uses the TasKit conservative parallel discrete event simulation (PDES) kernel. TasKit has been shown to be able to achieve improved parallel performance over existing conservative and optimistic PDES kernels, as well as improved sequential performance over an existing central-event-list based kernel. This paper explains the modifications that have been made to TasKit to enable real-time operation along with the emulator interface that allows the IP network simulation running in the TasKit kernel to interact with real IP clients. Initial emulator performance data is included.
Strong reasons exist for executing a large-scale discrete-event simulation on a cluster of processor nodes (each of which may be a shared-memory multiprocessor or a uniprocessor). This is the architecture of the large...
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ISBN:
(纸本)076951104X;0769511058
Strong reasons exist for executing a large-scale discrete-event simulation on a cluster of processor nodes (each of which may be a shared-memory multiprocessor or a uniprocessor). This is the architecture of the largest scale parallel machines, and so the largest simulation problems can only be solved this way. It is a common architecture even in less esoteric settings, and is suitable for memory-bound simulations. This paper describes our approach to porting the SSF simulation kernel to this architecture, using the Message Passing Interface (MPI) system. The notable feature of this transformation is to support an efficient two-level synchronization and communication scheme that addresses cost discrepancies between shared-memory and distributed memory. In the initial implementation, we use a globally synchronous approach between distributed-memory noes, and an asynchronous shared-memory approach within a SMP cluster. The SSF API reflects inherently shared-memory assumptions;we report therefore on our approach for porting an SSF kernel to a cluster of SMP nodes. Experimental results on two architectures are described, for a model of TCP/IP traffic flows over a hierarchical network. The performance on a distributed network of commodity SMPs connected through ethernet is seen to frequently exceed performance on a Sun shared-memory multiprocessor.
While the PADS community has traditionally focused on - and done a great job with - the technical aspects of developing simulations that run fast and can be connected to other simulations, it has paid little or no att...
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ISBN:
(纸本)0769506771
While the PADS community has traditionally focused on - and done a great job with - the technical aspects of developing simulations that run fast and can be connected to other simulations, it has paid little or no attention to the overall strategies required to produce a marketable, useful, and successful parallelsimulation. This lack of market focus has led to many fears of the demise of the PADS community, complaints of its lack of general acceptance by the broader simulation community, and predictions that it will become merely another venue for simulation interconnection. These fears, complaints, and predictions are unnecessary. There are several examples of successful parallelsimulations - in domains as far apart as aviation modeling and wargames. What can we learn from their successes? How can we translate their general acceptance into other parallelsimulation domains? Are there market opportunities that we are missing? In short, what is the parallelsimulation community lacking, and what does it need to do in order to be more successful? The purpose of this talk is to begin a discussion on the answers to these questions (as opposed to definitively answering them). We will draw on numerous examples of successful applications, and make some concrete suggestions for furthering the community.
A novel micro-kernel approach to building parallel/distributedsimulation systems is presented. Using this approach, a unified system architecture is developed for incorporating, multiple types of simulation processes...
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ISBN:
(纸本)0769523838
A novel micro-kernel approach to building parallel/distributedsimulation systems is presented. Using this approach, a unified system architecture is developed for incorporating, multiple types of simulation processes. The processes hold potential to employ a variety of synchronization mechanisms, and could even alter their choice of mechanism dynamically. Supported mechanisms include traditional lookahead-based conservative and state saving-based optimistic execution approaches. Also supported are newer mechanisms such as reverse computation-based optimistic execution and aggregation-based event processing, all within a single parsimonious application programming interface. The internal implementation and a preliminary performance evaluation of this interface are presented in mu sik, which is an efficient parallel/distributed realization of the microkernel architecture in C++.
This paper addresses the issue of efficient and accurate performance prediction of large-scale message-passing applications on high performance architectures using simulation. Such simulators are often based on parall...
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ISBN:
(纸本)076951104X;0769511058
This paper addresses the issue of efficient and accurate performance prediction of large-scale message-passing applications on high performance architectures using simulation. Such simulators are often based on parallel discrete event simulation, typically using the conservative protocol to synchronize the simulation threads. The paper considers how a compiler can be used to automatically extract information about the lookahead present in the application, and how this can be used to improve the performance of the null protocol used for synchronization. These techniques are implemented in the MPI-Sim simulator and dHPF compiler, which had previously been extended to work together for optimizing the simulation of local computational components of an application. The results show that the availability of lookahead information improves the runtime of the simulator by factors of magnitude, with 30-60% improvements being typical for the real-world codes. The experiments also show that these improvements are directly correlated with reductions in the number of null messages required by the simulations.
parallel Monte Carlo simulation requires reliable RNGs. For sequential machines, good generators exist. A is not at all trivial to find high-quality RNGs for parallel machines. In this paper we present a short review ...
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ISBN:
(纸本)0818684577
parallel Monte Carlo simulation requires reliable RNGs. For sequential machines, good generators exist. A is not at all trivial to find high-quality RNGs for parallel machines. In this paper we present a short review of the main concepts to produce random numbers on parallel processors and, further, we illustrate some phenomena that occur with parallelization.
Real-time distributedsimulations, such as on-line gaming or military training simulations are normally considered to be non-deterministic. Analysis of these simulations is therefore difficult depending solely on logg...
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ISBN:
(纸本)0769506771
Real-time distributedsimulations, such as on-line gaming or military training simulations are normally considered to be non-deterministic. Analysis of these simulations is therefore difficult depending solely on logging and runtime observations. This paper explores art approach for removing one major source of nondeterminism in these simulations, thereby allowing repeatable executions. Specifically, we use a synchronization protocol to ensure repeatable delivery of messages. Through limited instrumentation of the simulation code, we maintain a virtual time clock, by which message delivery! is governed. The additional overhead imposed by the scheme is shown to be reasonable, although additional reductions in this overhead are anticipated The results are demonstrated in the context of a simple combat model whose only source of non-determinism is communications latency. The simulation is shown to be tirade repeatable, and the perturbation on the execution compared to the nonrepeatable execution small. The paper is one step in bridging the gap between the traditional PDES perspective and real-time simulation world.
If a model shall be executed in a parallel, distributed instead of a sequential manner typically the entire simulation engine has to be exchanged. To adapt the simulation layer more easily to the requirements of a con...
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ISBN:
(纸本)0769521118
If a model shall be executed in a parallel, distributed instead of a sequential manner typically the entire simulation engine has to be exchanged. To adapt the simulation layer more easily to the requirements of a concrete model to be run in a specific environment a component based simulation layer has been developed for JAMES. A set of different simulator components demonstrates that a component-based design facilitates the exchange of simulators and their combination.
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