Performance Implications at the Intersection of AF_XDP and Programmable NICs

AF_XDP is emerging as an easier way to implement zero-copy network bypass applications. This is because it allows mixed-mode deployments, where zero-copy and socket-based applications share the same NIC. However, AF_XDP relies on NIC hardware and driver features, but implementing these features on programmable NICs adds resource overheads and increases development complexity and thus might not be desirable. To address this, we examine the feasibility of using eBPF based kernel extensibility to implement the required features, and report on the tradeoff between an eBPF and a native NIC implementation. Our analysis involved updating the OpenNIC driver to support the loading of eBPF/XDP programs and zero-copy AF_XDP. Our implementation is of independent interest because it makes it easier to develop and evaluate alternate designs for mixed-mode zero-copy deployments, and new NIC accelerated applications. Our implementation is open-sourced