Comparison of the circulating multisequencer, the multi-tokens and the consensus algorithms in a real-time distributed transactional system

摘要

A real-time distributed transactional system is defined as being a system composed of customers and severs interconnected by a communication network. Customers generate transactions which have temporal constraints and must be executed beofre their deadlines. To schedule thee transactions the circulating mutisequencer, the multi-tokens and the consensus algorithms have been considered to obtain a global view of the system. Mathematical models have been developed to obtain the overage stay time of a transaction within the system and the transaction deadline miss probability. Thee models use a bulk arrival M/G/I station with K classes of customers where bulks are scheduled according to EDF with in a group and with the HOL discipline for the algorithm operating. This allowed us to determine the minimum relative deadline, to afect to a generated transaction, to guarantee a given probability p that the transaction does not miss its deadline. The system is then called p-feasible. This study enables to determine the optimal parameters of the system and shown that the circulating mutisequencer algorithm presents the best results.