OXDP: Offloading XDP to SmartNIC for Accelerating Packet Processing

Traditional kernel network processing suffers from high delay and overhead, which has become the bottleneck of high-speed networks. A natural method to accelerate packet processing is to bypass the kernel network stack and process packets in user space directly, e.g., DPDK. However, due to many network functions are implemented in the kernel network stack, bypassing the stack means that we need to redesign the required functions elsewhere, leading to poor compatibility. One promising technology to address this problem is called eXpress Data Path (XDP), which can support high-performance packet processing while preserving the kernel stack. However, existing solutions mainly run XDP in software mode, resulting in relatively poor packet processing performance. Fortunately, with the development of programmable hardware, running XDP in hardware mode is a more promising approach. Thus, in this paper, we design and implement OXDP, the first-of-its-kind work on accelerating packet processing by offloading XDP to SmartNICs. Since today's SmartNICs are still subject to some limitations regarding the rigid runtime environment, it is non-trivial to offload XDP to SmartNICs. To address this issue, OXDP performs best-effort offloading based on the primitive packet operations, thus maximizing the use of SmartNIC's resources. Specifically, OXDP splits the forwarding function into two parts, one part offloading on SmartNIC with hardware XDP and the other part deploying on host. We evaluate the efficiency of OXDP with comprehensive experiments. Evaluation results show that the forwarding rate of OXDP can reach 18.7 Mpps, which improves 30x compared with the single-core performance of software XDP.