Implement Flash Attention Backend in SGLang - Basics and KV Cache

Authored by Biao He Qingquan Song 0x0. Introduction In the past few weeks, we’ve implemented the Flash Attention Backend end-to-end in SGLang, which is now the default attention backend as of SGLang 0.4.6 release . Throughout this journey, we learned a lot about how Attention Backend functions in modern LLM serving engines and developed a deeper understanding of Flash Attention itself. In this…