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QUIC is not quick enough over fast internet | Hacker News

news.ycombinator.com · 10,138 words · saved by 1 readers

- syscall interfaces are a mess, the primitive APIs are too slow for regular sized packets (~1500 bytes), the overhead is too high. GSO helps but it’s a horrible API, and it’s been buggy even lately due to complexity and poor code standards. - the syscall costs got even higher with spectre mitigation - and this story likely isn’t over. We need a replacement for the BSD sockets / POSIX APIs they’re terrible this decade. Yes, uring is fancy, but there’s a tutorial level API middle ground possible that should be safe and 10x less overhead without resorting to uring level complexity. - system udp buffers are far too small by default - they’re much much smaller than their tcp siblings, essentially no one but experts have been using them, and experts just retune stuff. - udp stack optimizations are possible (such as possible route lookup reuse without connect(2)), gso demonstrates this, though as noted above gso is highly fallible, quite expensive itself, and the design is wholly unnecessari

There are a number of concrete problems: - syscall interfaces are a mess, the primitive APIs are too slow for regular sized packets (~1500 bytes), the overhead is too high. GSO helps but it’s a horrible API, and it’s been buggy even lately due to complexity and poor code standards. - the syscall costs got even higher with spectre mitigation - and this story likely isn’t over. We need a replacement for the BSD sockets / POSIX APIs they’re terrible this decade. Yes, uring is fancy, but there’s a tutorial level API middle ground possible that should be safe and 10x less overhead without…

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