Despite unix(7) offering much more features than pipe(7),
it is much faster. There is however two features unix(7)
does not have: there is no guarantee that small writes are
atomic, there is not support for splice(2)/tee(2) which
is extremely efficient, and file descriptor hijacking is
not support. The latter is a double-sided sword: it [the
lack of support] increases security, but other processes'
file cannot be opened and programs must treat /dev/fd/
paths especially.

![performance graph](graph.png)

send(3)/recv(3) is marginally faster than write(3)/read(3).