A fault recovery protocol for brokers in centralized publish-subscribe systems targeting multiprocessor systems-on-chips

Abstract

The publish-subscribe programming model has been an alternative to the design of data-intensive distributed applications in many domains. Recently, this model has been ported to the domain of Multiprocessor Systems-on-Chips, in which applications must use the underlying Network-on-Chip communication infrastructure effectively due to restrictions on the architecture such as low power consumption and limited memory size. In such a scenario, the publish-subscribe model fulfills some of these requirements while providing high-level access to the network hardware to programmers, thus contributing to software quality. However, the publish-subscribe model relies on a single process dedicated to orchestrating the communication at the application level, the broker. Should a broker process crash, the communication between associated nodes may experience delays, downtime, or even inconsistent data. In extreme cases, communication is definitively ruined. Thus, a recovery strategy for brokers in the publish-subscribe model becomes crucial when the application has safety requirements. In this work, we extend a publish-subscribe protocol to add redundancy to brokers’ sensitive data. Besides, we provide a recovery protocol to recover brokers in case of a failure. We also provide analytical models to estimate the communication overhead of our approach. We validate our approach in two distinct MPSoC platforms. The results show that our approach inserts a small memory footprint to the system while providing minimal system downtime during recovery.