One CPU Core Inspects 28.8M Packets/Sec: How XDP Rewrites Network Processing

blaizedsouza · x · 2026-09-17

A long thread explaining Linux XDP/eBPF networking, plus the author's open-source learning project ringzero, a Katran-style L4 load balancer forwarding 9M+ packets/sec.

XDP runs inside the NIC driver before the kernel allocates a socket buffer, letting a single core inspect 28.8M packets per second and drop or keep them instantly. Production examples: Cloudflare drops 10M+ packets/sec per core and has auto-mitigated 100+ attacks above 2 Bpps including a 3.8 Tbps flood, fully automated; Meta's Katran load balancer, deployed in every Facebook data center, is 10-100x faster than iptables-style setups (1M packets/sec per core at 90% CPU). The author open-sourced ringzero (eBPF data plane in C, Zig control plane) as a readable-afternoon demo, not for production.

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