  Load balancers are pervasively used inside today's clouds to scalably
distribute network requests across data center servers. Given the extensive use
of load balancers and their associated operating costs, several efforts have
focused on improving their efficiency by implementing Layer-4 load-balancing
logic within the kernel or using hardware acceleration. This work explores
whether the more complex and connection-oriented Layer-7 load-balancing
capability can also benefit from hardware acceleration. In particular, we
target the offloading of load-balancing capability onto programmable SmartNICs.
We fully leverage the cost and energy efficiency of SmartNICs using three key
ideas. First, we argue that a full and complex TCP/IP stack is not required for
Layer-7 load balancers and instead propose a lightweight forwarding agent on
the SmartNIC. Second, we develop connection management data structures with a
high degree of concurrency with minimal synchronization when executed on
multi-core SmartNICs. Finally, we describe how the load-balancing logic could
be accelerated using custom packet-processing accelerators on SmartNICs. We
prototype Laconic on two types of SmartNIC hardware, achieving over 150 Gbps
throughput using all cores on BlueField-2, while a single SmartNIC core
achieves 8.7x higher throughput and comparable latency to Nginx on a single x86
core.
