> FreeBSD's setproctitle() is a bit slow because it contains a syscall
> or two, so people often run PostgreSQL with update_process_title set
> to off on that OS. That makes the user experience not quite as nice
> as Linux. As a weekend learn-me-some-kernel-hacking project I fixed
> that and got the patch committed to FreeBSD 12, though I was asked to
> use a new libc entry point _fast(). Here's a patch to teach
> PostgreSQL about that. It doesn't have much effect on small systems,
> but it makes "pgbench -c 40 -j 40 -S -M prepared" do ~10% more
> transactions per second on an AWS m4.10xlarge instance.
I am curious why they asked you to use a new libc entry point. The
function signatures are the same. More people could benefit from
making the existing function faster.