We present a conservative strategy for spatially decomposed parallel discrete event battlefield simulation. The traditional null message algorithm provides a foundation from which a mapping to generic simulation attri...
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We present a conservative strategy for spatially decomposed parallel discrete event battlefield simulation. The traditional null message algorithm provides a foundation from which a mapping to generic simulation attributes can be made. We informally discuss preservation of logical correctness and freedom from deadlock. Experimental results demonstrate the potential execution time savings when load imbalance is not dominant;more importantly, they highlight improvement opportunities in spite of potential load imbalance. The net result is that a very reasonable performance gain can be delivered for little effort in a way that supports good simulation system design principles. The approach is straightforward and can be easily implemented as part of a more general sequential or parallelsimulation support environment. While the approach is expressed in terms of battlefield simulation, its essence applies to many simulation applications.
simulation of large-scale networks requires enormous amounts of memory and processing time. One way of speeding up these simulations is to distribute the model over a number of connected workstations. However, this in...
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ISBN:
(纸本)0769523838
simulation of large-scale networks requires enormous amounts of memory and processing time. One way of speeding up these simulations is to distribute the model over a number of connected workstations. However, this introduces inefficiencies caused by the need for synchronization and message passing between machines. In distributed network simulation, one of the factors affecting message passing overhead is the amount of cross-traffic between machines. We perform an independent benchmark of the parallel/distributed Network Simulator (PDNS) based on experimental results processed at the Australian Centre for Advanced Computing and Communications (AC3) supercomputing cluster. We measure the effect of cross-traffic on wall-clock time needed to complete a simulation for a set of basic network topologies by comparing the result with the wall-clock time needed on a single processor. Our results show that although efficiency is reduced with large amounts of cross-traffic, speedup can still be achieved with PDNS. With these results, we developed a performance model that can be used as a guideline for designing future simulations.
In distributed wargame simulations, the states of simulation entities need to be updated and sent to other simulation nodes in a timely manner, which may incur high overhead on the network. Thus, how to efficiently us...
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ISBN:
(纸本)0769521118
In distributed wargame simulations, the states of simulation entities need to be updated and sent to other simulation nodes in a timely manner, which may incur high overhead on the network. Thus, how to efficiently use the limited bandwidth of the network is very important to the performance of distributed wargame simulations. In this paper, a utility model is proposed to evaluate the relative importance of a simulation entity. In our proposed utility model, the utility of an entity is determined by the number of entities on which this entity may have influence and the distances between this entity and the entities within its area of influence. Based on the utility model, we may devise some flexible updating mechanisms which can utilize the band-width more efficiently. For example, the state updates of an important entity which may have great influence on the simulation could be sent to other nodes with a high frequency;on the other hand, the state updates of an entity with little importance may be sent to other simulation nodes with a low frequency. In this paper, we will focus on the utility computation of a simulation entity rather than the flexible state updating mechanisms for the simulation entities. Our proposed utility computation mechanism is general and can be easily implemented using the HLA services. Experimental results show that the utility computation mechanism incurs little overhead.
In this paper we study message flow processes in distributed simulators of open queueing networks. We develop and study queueing models for distributed simulators with maximum lookahead sequencing. We characterize the...
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In this paper we study message flow processes in distributed simulators of open queueing networks. We develop and study queueing models for distributed simulators with maximum lookahead sequencing. We characterize the 'external' arrival process, and the message feedback process in the simulator of a simple queueing network with feedback. We show that a certain 'natural' modelling construct for the arrival process is exactly correct, whereas an 'obvious' model for the feedback process is wrong;we then show how to develop the correct model. Our analysis throws light on the stability of distributed simulators of queueing networks with feedback. We show how the stability of such simulators depends on the parameters of the queueing network.
The concept of strong groups is introduced to describe the structure of simulation models. It is shown that logical processes within strong groups process at approximately the same rate and that different strong group...
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The concept of strong groups is introduced to describe the structure of simulation models. It is shown that logical processes within strong groups process at approximately the same rate and that different strong groups can progress at different rates. An algorithm based on the rates of the strong groups is presented to balance the load among the physical processors and for flow control.
The simulation of wireless systems such as cellular or personal communication systems comprises both discrete and continuous time processes. To accelerate these simulations, we propose the use of interval jumping, a n...
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The simulation of wireless systems such as cellular or personal communication systems comprises both discrete and continuous time processes. To accelerate these simulations, we propose the use of interval jumping, a novel technique that allows the execution of a continuous time model to proceed in irregularly sized jumps rather than in the traditional time-stepped manner. The foundations for this mechanism are laid out in the light of the simulation of a complex simulation model which includes radio propagation, channel allocation, transmitter power control and user mobility. We conclude with experimental results comparing sequential and parallel execution of these accelerated simulations which indicate the good potential of our technique.
One of the methods used to reduce the time spent simulating VHDL designs is by parallelizing the simulation. In this paper, we describe the implementation of an object-oriented Time Warp simulator for VHDL on an actor...
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One of the methods used to reduce the time spent simulating VHDL designs is by parallelizing the simulation. In this paper, we describe the implementation of an object-oriented Time Warp simulator for VHDL on an actor based environment. The actor model of computation allows the exploitation of the grained parallelism in a truly asynchronous manner and allows for the overlap of computation with communication. Some preliminary results obtained by simulating a set of multipliers and some ISCAS benchmark circuits are provided. In addition, the importance of placing processes based on circuit partitioning techniques for improving runtimes and scalability is demonstrated. Results are reported on a Sun SPARCServer 1000 and an Intel Paragon.
We study the adaptation of an optimistic Time Warp kernel to cross-cluster computing on the Grid. Wide area communication, the primary source of overhead, is off-loaded onto dedicated routing processes. This allows th...
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ISBN:
(纸本)0769521118
We study the adaptation of an optimistic Time Warp kernel to cross-cluster computing on the Grid. Wide area communication, the primary source of overhead, is off-loaded onto dedicated routing processes. This allows the simulation processes to run at full speed and it thus significantly decreases the performance gap caused by the wide area distribution. Further improvements are obtained by employing message aggregation on the wide area links. We achieve many of our objectives for lazy cancellation and moderate communication, but high communication rates with aggressive cancellation remains a challenge.
There is a wide-spread usage of hardware design languages(HDL) to speed up the time-to-market for the design of modern digital systems. Verification engineers can simulate hardware in order to verify its performance a...
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ISBN:
(纸本)0769519709
There is a wide-spread usage of hardware design languages(HDL) to speed up the time-to-market for the design of modern digital systems. Verification engineers can simulate hardware in order to verify its performance and correctness with help of an HDL. However simulation can't keep pace with the growth in size and complexity of circuits and has become a bottleneck of the design process. distributed HDL simulation on a cluster of workstations has the potential to provide a cost-effective solution to this problem. In this paper we describe the design and implementation of DVS, an object-oriented framework for distributed Verilog simulation. Verilog is an HDL which sees wide industrial use. DVS is an outgrowth of Clustered Time Warp, originally developed for logic simulation. The design of the framework emphasizes simplicity and extensibility and aims to accommodate experiments involving partitioning and dynamic load balancing. Preliminary results obtained by simulating a 16bit multiplier are presented.
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