An analysis of fairness and overhead in the arbitration protocol of the IEEE futurebus standard

Futurebus is a standard system bus architecture for multiprocessor systems, approved as IEEE standard P.896 in 1987. The protocol set defined in the standard is a complex one because it pursues high performance and technology independence. However, after the approval of the standard, study on Futurebus+ was begun, which aimed at achieving higher transfer performance, robustness, and real-time performances. The evaluation for the Futurebus was left untouched. Therefore, in this article, we evaluate the performance of the bus arbitration protocol of the Futurebus by a theoretical analysis. The bus arbitration protocol is one of the features of the Futurebus asynchronous transfer protocol. As a result of this study, we have found that Futurebus has unfairness in arbitration and the possibility of inducing overhead in a mechanism to avoid a starvation state.