The BXI Interconnect Architecture

BXI, Bull eXascale Interconnect, is the new interconnection network developed by Atos for High Performance Computing. In this paper, we first present an overview of the BXI network. The BXI network is designed and optimized for HPC workloads at very large scale. It is based on the Portals 4 protocol and permits a complete offload of communication primitives in hardware, thus enabling independent progress of computation and communication. We then describe the two BXI ASIC components, the network interface and the BXI switch, and the BXI software environment. We finally explain how the Bull exascale platform integrates BXI to build a large scale parallel system and we give some performance estimations.