Robert Watson, University of Cambridge - August 2015

Over the last two years, Ilias Marinos, a doctoral student at the University of Cambridge, in collaboration with Mark Handley (UCL) and Robert Watson, have been pursuing a research project on clean-slate network-stack design and network-stack specialization, testing two hypotheses: (1) that current network-stack designs, dating from the 1980s, fail to exploit contemporary architectural features for performance and hence suffer significant penalties – and that re-architecting fundamental aspects of stack design with micro-architectural awareness will dramatically improve performance; and (2) that the generality in current network-stack designs, substantially hampers application performance whereas ‘specialized’ stacks that integrate applications with the network stack itself can offer dramatic performance improvement opportunities. The team has prototyped a clean-slate, userspace TCP stack, published at SIGCOMM 2014, illustrating these effects on high-performance network traffic for in-DRAM workloads, experiencing substantial performance benefits (e.g., 6x throughput with a tiny fraction of CPU utilization) for HTTP and DNS workloads. The team proposes to extend this work to include a clean-slate network-storage stack based on a new userspace ‘diskmap’ facility for PCI-attached flash to cater to workloads with footprints greater than DRAM size – e.g., high-volume HTTP/HTTPS content-delivery networks (CDNs), and RPC-based filesystem services. Where sensible and appropriate, the team propose to open source (and upstream) artifacts developed during this work under a BSD-style license, as well as pursue collaboration opportunities with NetApp.