Abstract
Computer clusters equipped with reconfigurable accelerators have shown promise in high performance computing. This paper explores novel ways of customising data communication between accelerator nodes, which is often a bottleneck when scaling up the cluster size. Based on the direct connection of high speed serial links between advanced reconfigurable devices, we develop and evaluate CusComNet, a scalable, flexible and efficient communication framework. The CusComNet framework is built around customisable, packet-based communication and supports three main types of customisation: packet protocol customisation, system-level customisation, and prioritised communication customisation. A performance model for estimating CusComNet's communication latency is proposed and demonstrated. Our framework is applied to a 16-node cluster, each node of which contains an FPGA accelerator which can be connected directly to other FPGA accelerators. The proposed framework can be used to improve the scalability of a reconfigurable cluster by involving more nodes in a single application. Performance measurements show high efficiency data throughput for both large and small data volumes, as well as low communication overhead.