Getting back what was lost in the era of high-speed software packet processing
Marcelo Abranches, Oliver Michel, Eric R. Keller · 2022
The need for high performance and custom software-based packet processing has resulted in decades of research. Most proposals bypass or replace the Linux networking stack with the unfortunate consequence of sacrificing the rich and robust functionality available within Linux and the ecosystem of management programs and control-plane software built on top of it. In this paper, we propose to rethink the design of the Linux network stack to address its shortcomings rather than creating alternative pipelines. This re-design involves (1) decomposing packet processing into a fast path and a slow path, and (2) transparently and dynamically creating a custom fast path that only implements the processing tasks currently configured. We leverage Linux's eXpress Data Path to load efficient and small fast-path modules, leaving the kernel stack to serve as the slow path. To materialize this vision, this paper introduces Transparent Network Acceleration (TNA), a prototype system that automatically generates a minimal data path based on introspection of the current networking configuration, avoiding many of the networking stack overheads in Linux while ensuring high performance and maintaining Linux's rich set of functionalities.