> 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.