Comment by erik_seaberg
3 years ago
The kernel has to buffer everything you send in a sliding window, to retry missed acks. Userspace buffering only reduces syscalls.
A lot of people with strong preferences about segment boundaries and timing are arguing with TCP and probably shouldn’t be using it.
> Userspace buffering only reduces syscalls.
"only". The kernel also buffers disk writes, but god help you if you're writing files to disk byte by byte.