Arrakis: The operating system is the control plane

Recent device hardware trends enable a new approach to the design of network servers. In a traditional 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 designed and implemented a new operating system, Arrakis, that splits the traditional role of the kernel in two. Applications have direct access to virtualized I/O devices, allowing most I/O operations to skip the kernel entirely. The Arrakis kernel operates only in the control plane. We describe the the hardware and software changes needed to take advantage of this new abstraction, and we illustrate its power by showing significant latency and throughput improvements for network server applications relative to a well-tuned Linux implementation. 1