In this work we focus on a new technique for making cloning of parallelsimulations more efficient. Cloning provides a means for running multiple similar simulations in parallel where many computations are shared rath...
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ISBN:
(纸本)0769521118
In this work we focus on a new technique for making cloning of parallelsimulations more efficient. Cloning provides a means for running multiple similar simulations in parallel where many computations are shared rather than repeated [12]. A simulation is cloned on an event for a particular set of logical processes, creating new LP clones. The clones diverge as messages from the new LPs arrive at uncloned LPs. Until replication, all the computations for a particular LP are shared between the clones. simulation kernels using cloning achieve efficiency by incrementally replicating logical processes as necessary. This enables regions of the simulation that have not been affected to use the same computations for both the new and old clone. Clearly, the longer replication can be delayed, the more efficient the simulation. We hypothesize that in many cases replication takes place before it is strictly necessary. We propose just-in-time cloning that addresses this issue by relaxing the constraints of simulation cloning to further benefit from shared computations.
In this work we illustrate the design and implementation guidelines of a recently developed middleware defined to support the parallel and distributedsimulation of large scale, complex and dynamically interacting sys...
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ISBN:
(纸本)0769524478
In this work we illustrate the design and implementation guidelines of a recently developed middleware defined to support the parallel and distributedsimulation of large scale, complex and dynamically interacting system models. The distributedsimulation of complex system models, may suffer the communication and synchronization required to maintain the causality constraints between distributed model components. We designed and implemented the ARTIS middleware as a new framework by incorporating a set of features that allow adaptive optimization by exploiting many complex and dynamic model and distributedsimulation characteristics. As an example, a dynamic migration mechanism for the run-time adaptive allocation of model entities has been designed and exploited for dynamic load and communication balancing. Optimizations have been introduced to obtain the maximum advantage from heterogeneous and asymmetric communication systems, from shared memory to LAN and Internet communication. Other optimizations have been introduced by the exploitation of concurrent replications of parallel and distributedsimulations, in order to increase the resources utilization and to maximize the speedup of simulation processes. Solutions have been designed, implemented and tuned to obtain a significant reduction in the communication and synchronization overheads between the physical execution units, and an increased model scalability and simulation speedup, even in worst-case modeling assumptions and simulation scenarios.
The proceedings contain 70 papers. The topics discussed include: programming shared virtual memory multiprocessors;parallelsimulation of a multi-dimensional computational fluid dynamics problem;computing the singular...
ISBN:
(纸本)0818673761
The proceedings contain 70 papers. The topics discussed include: programming shared virtual memory multiprocessors;parallelsimulation of a multi-dimensional computational fluid dynamics problem;computing the singular values of the product of two matrices in distributed memory multiprocessors;a latency-hiding MIMD wavelet transform;simulation of chaotic iterative processes in speed-independent computing networks;sparse householder QR factorization on a mesh;and the role of associative memory in virtual shared memory architectures: a price-performance comparison.
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.
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.
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.
We propose in this paper two new asynchronous parallel algorithms for test set partitioned fault simulation. The algorithms are based on a new two-stage approach to parallelizing fault simulation for sequential VLSI c...
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We propose in this paper two new asynchronous parallel algorithms for test set partitioned fault simulation. The algorithms are based on a new two-stage approach to parallelizing fault simulation for sequential VLSI circuits in which the test set is partitioned among the available processors. These algorithms provide the same result as the previous synchronous two stage approach. However, due to the dynamic characteristics of these algorithms and due to the fact that there is very minimal redundant work, they run faster than the previous synchronous approach. A theoretical analysis comparing the various algorithms is also given to provide an insight into these algorithms. The implementations were done in MPI and are therefore portable to many parallel platforms. Results are shown for a shared memory multiprocessor.
With distributedsimulation, existing simulations, even from different disciplines, can be reused or made to interoperate. The efficiency of this technique is however not firmly established and it depends on the abili...
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ISBN:
(纸本)0769518532
With distributedsimulation, existing simulations, even from different disciplines, can be reused or made to interoperate. The efficiency of this technique is however not firmly established and it depends on the ability to satisfy a number of requirements, especially concerning simulation performance. The performance depends to a large extent on the structure and scaling of architectural components of the simulation execution platform. In this paper, we present an approach to address this problem: the design of models to capture the main characteristics of distributedsimulations, run-time infrastructures and network architectures, and the development of a tool to predict performances. This tool, which is a simulator of HLA simulations is written by using HLA and is evaluated on three test applications.
The High-Level Architecture (HLA) provides a common architecture for distributed modeling and simulation. In its original form, the HLA allows a number of simulations to be joined together into a federation using a si...
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ISBN:
(纸本)0769518532
The High-Level Architecture (HLA) provides a common architecture for distributed modeling and simulation. In its original form, the HLA allows a number of simulations to be joined together into a federation using a single run time infrastructure. Recently there has been an interest in joining multiple such federations together using a mediating unit, called an HLA "bridge." This paper presents the results of an in-depth study of the feasibility of an HLA bridge in the context of the current HLA interface specification. Problems and solutions are discussed and illustrated using particular HLA services.
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