Remote TCP Connection Offload and Applications

Layer 7 load balancers (L7LBs) play an important role in per-request server selection within long-lived connections and transport- or application-layer protocol translation. However, L7LBs introduce substantial CPU and network overhead. We present XO, which enables an L7LB to offload transport-layer and application request processing to backend servers at request granularity. XO outperforms conventional L7LBs by 27–365% in throughput through efficient utilization of server CPU and network resources. We apply XO to two real-world applications, Ceph and nginx, improving throughput by up to 135% and 300%, respectively.