Keep net working - on a dependable and fast networking stack

For many years, multiserver1 operating systems have been demonstrating, by their design, high dependability and reliability. However, the design has inherent performance implications which were not easy to overcome. Until now the context switching and kernel involvement in the message passing was the performance bottleneck for such systems to get broader acceptance beyond niche domains. In contrast to other areas of software development where fitting the software to the parallelism is difficult, the new multicore hardware is a great match for the multiserver systems. We can run individual servers on different cores. This opens more room for further decomposition of the existing servers and thus improving dependability and live-updatability. We discuss in general the implications for the multiserver systems design and cover in detail the implementation and evaluation of a more dependable networking stack. We split the single stack into multiple servers which run on dedicated cores and communicate without kernel involvement. We think that the performance problems that have dogged multiserver operating systems since their inception should be reconsidered: it is possible to make multiserver systems fast on multicores.