FBUFS: A high-bandwith cross-domain transfer facility

Abstract

We have designed and implemented a new operating system facility for I/O buffer management and data transfer across protection domain boundaries on shared memory machines. This facility, called fast buffers (FBUFS), combines virtual page remapping with shared virtual memory, and exploits locality in I/O traffic to achieve high throughput without compromising protection, security, or modularity. Its goal is to help deliver the high bandwidth afforded by emerging high-speed networks to user-level processes, both in monolithic and microkernel-based operating systems. This paper outlines the requirements for a cross-domain transfer facility, describes the design of the FBUF mechanism that meets these requirements, and experimentally quantifies the impact of FBUFS on network performance.