The I/O Driven Server: From SmartNICs to Data Movement Controllers

Many researchers are turning to SmartNIC offloads to improve the performance of high-performance networked systems. In this editorial, I discuss why SmartNICs are an especially powerful form factor for improving I/O intensive applications, and how their position in the dataplane enables them to take on central role in managing I/O. Rather than focusing on the benefits of individual offloads, this paper aims to explore the position of SmartNICs in the overall system integration of datacenter servers at the hardware and software level. I argue that SmartNICs should be viewed as 'data movement controllers' (NIC-DMCs) which are responsible for tasks involved in moving data between network, CPU, accelerators, and other endpoints: multiplexing/steering, interfacing between protocols, and enforcing I/O policies. I then enumerate open questions in how the hardware and software systems of the future will evolve to accommodate a dedicated NIC-DMC which is independent of the CPU complex.