Optimizing HTTP/2 prioritization with BBR and tcp_notsent_lowat

Optimizing HTTP/2 performance requires good support for resource prioritization across the networking stack. This article discusses interactions between web servers, Operating Systems, and networks, and how to tune a server for optimal end-user performance. On Linux 4.9 kernels and later, enabling BBR congestion control and setting tcp_notsent_lowat to 16KB can improve HTTP/2 prioritization reliability. Proper resource ordering can significantly speed up page rendering, especially on slower connections. Tuning for TCP_NOTSENT_LOWAT of 16KB and using BBR congestion control can help reduce buffering and improve end-user performance with HTTP/2.