Effect of non-uniform memory request on the performance of buffered multiprocessor systems

Performance analysis of multiple-bus systems is usually carried out under t he assumption of a uniform memory request model. Hot spots arising in multi processor systems give rise to non-uniform memory requests. It is known tha t a hot spot memory request pattern results in a significant degradation in the performance of a buffered multistage interconnection network. The aim of this research is to study the effect of hot spots on the performance of buffered multiple-bus systems, and to compare the performance of buffered a nd unbuffered systems. Analytical models based on Markov chains have been d eveloped to determine the bandwidth of buffered multiple-bus systems in the presence of a hot spot memory request pattern. The models assume that unsu ccessful memory requests are queued in the buffers at the memory modules. F urthermore, processors with outstanding requests are not allowed to generat e new requests. The model allows a fast and inexpensive method to evaluate the performance of a buffered multiple-bus system in the presence of a hot spot memory request pattern. (C) 2001 Elsevier Science Ltd. All rights rese rved.