The New TCP Modules on the Block: A Performance Evaluation of TCP Pacing and TCP Small Queues

Google and the Bufferbloat community have designed several solutions to reduce Internet latency in recent years, involving different TCP-IP stack layers. One of these solutions is named TCP Small Queues (TSQ) and reduces a TCP flow latency by controlling the number of packets that each TCP socket can enqueue in the sender node. It works in conjunction with TCP Pacing (TP), which affects the actual TSQ size as a function of the TCP rate. This paper analyzes TSQ and TP’s performance through real-system tests over different networks’ bottlenecks, emphasizing Wi-Fi technologies, where their behavior strongly affects the Wi-Fi frame aggregation mechanism.