Arrakis: The Operating System is the Control Plane

Recent device hardware trends enable a new approach to the design of network server operating systems. In a tra-ditional operating system, the kernel mediates access to device hardware by server applications, to enforce process isolation as well as network and disk security. We have de-signed and implemented a new operating system, Arrakis, that splits the traditional role of the kernel in two. Applica-tions have direct access to virtualized I/O devices, allowing most I/O operations to skip the kernel entirely, while the kernel is re-engineered to provide network and disk pro-tection without kernel mediation of every operation. We describe the hardware and software changes needed to take advantage of this new abstraction, and we illustrate its power by showing improvements of 2-5 × in latency and 9 × in throughput for a popular persistent NoSQL store relative to a well-tuned Linux implementation.