Device Driver Issues in High-Performance Networking

High-performance networking requires attention to operating system support at the device driver level. Existing driver models, such as those of Unix, are not necessarily well-suited to supporting high-speed network interfaces. In fact, current drivers may represent a significant obstacle between applications and the high-speed network adapters they seek to exploit. Yet existing models cannot simply be discarded. Certain trends in RISC processor design can also tend to make existing device driver implementations less efficient. Specifically, many drivers make extensive use of operations which are becoming relatively more costly as RISC architectures evolve. This paper describes an effort currently underway to develop device drivers specifically designed to support high-speed network interfaces on RISC architectures. We have analyzed the operation of some existing commercial device driver implementations and modified one using several techniques. Taken together, these techniques promise to produce network device drivers which deliver the high level of performance demanded by todays igh speed networks.