We show that the LogP model is a valuable guide in the development of parallel algorithms and a good predictor of implementation performance. The model encourages the use of data layouts which minimize communication and balanced communication schedules which avoid contention. With an empirical model of local processor performance, LogP predictions closely match observed execution times on uniformly distributed keys across a broad range of problem and machine sizes. We find that communication performance is oblivious to the distribution of the key values, whereas the local processor performance is not; some communication phases are sensitive to the ordering of keys due to contention. Finally, our analysis shows that overhead is the most critical communication parameter in the sorting algorithms.
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Part of this work appeared in "Portability and Performance for Parallel Processing", Editors T. Hey and J. Ferrante, Copyright 1994 by John Wiley & Sons Ltd. Reproduced with permission from John Wiley & Sons, Ltd.
Split-C code of four sorting algorithm