uXDP: Frictionless XDP Deployments in Userspace

Modern network function (NF) deployments face a fundamental trade-off: kernel-based extended Berkeley Packet Filter (eBPF) NFs provide safety, portability, and an extensive tooling ecosystem, but are limited in performance, while kernel-bypass frameworks deliver high throughput but lack integrated verification and ease of deployment. We present uXDP, a new runtime that unifies these worlds by running unmodified, verified XDP programs in userspace. uXDP ensures compatibility and preserves the verification-driven safety, portability, and familiar workflows of eBPF while moving execution into the userspace, enabling more aggressive optimizations and flexibility. Without recompiling eBPF code, uXDP achieves throughput gains of up to 3.3× over in-kernel execution and improves Meta's Katran load balancer performance by 40%, all while retaining the trusted eBPF development model and deployment simplicity.