| Abstrakt: |
The traditional parallel processing assumes synchronous jobs, for which the processing can easily be planned before execution. On the other hand, the parallel processing is not usually considered for asynchronous jobs of a stochastic nature, such as the queueing network simulation, since the synchronization control of the processors is a problem. The advance processing has already been proposed as a control scheme for the processors in the asynchronous job parallel processing system. In this scheme, each processor performs the processing, thereby ignoring its relation to other processors. Thus the result of the processing is cancelled when a contradiction is found. Unfortunately, the processor may be too advanced in the execution, which results in a large number of cancelling, thus decreasing the processing ability per processor. From such a viewpoint, this paper discusses the limited-advance processing which is the improved scheme of advance processing. In this scheme, if the processor performs a certain amount of processing, it judges itself as too advanced, and awaits the progress of other processors. It is shown that there exists the optimum advance limit in this scheme, which is a function of the number of processors. The proposed scheme is analyzed to predict the optimum advance limit. In the analysis, the relation between the simulation time and the real time is specified, and the distribution overhead, cancelling time and the number of iterations are discussed. Comparing the result of numerical computation in the analysis and the result of measurement in the prototype system, the validity of the analysis is verified. [ABSTRACT FROM AUTHOR] |
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