QUIC is a new transport protocol on top of UDP, transporting a large portion of the Internet traffic today. UDP I/O performance is crucial for QUIC implementations, where e.g. system call overhead can significantly impact throughput at high network speeds. To improve QUIC throughput, Firefox is switching to a modern UDP IO stack in Rust, using mechanisms like recvmmsg, and GRO across Linux, Windows, and Android.

This talk gives a high level overview of Firefox’s HTTP3 / QUIC / UDP stack, followed by a deep dive into the various performance improvements landing in Firefox. Learn how we are making Firefox even faster and how you too can leverage these techniques to optimize your application.