RISC-V Global Forum 2020

Over the past eighteen months OmniXtend has become the de facto standard for building multi-socket RISC-V systems. Recent efforts within the Interconnects Workgroup in CHIPS Alliance resulted in the definition of an initialization and configuration protocol which enables the construction of massively parallel systems of arbitrary size. This is a simple yet race-free approach to setting up any number of coherent endpoints at boot. It enables different system models: a single instance of an operating system over several nodes with Non-Uniform Memory Access (NUMA) or independent instances of operating systems on different nodes sharing global memory coherently and peripherals non-coherently. This talk will cover the basics of the protocol and the currently enabled usage scenarios, as well as the future vision for fault-tolerance and coherent hotplug.