Multi-threaded operation?

[Havard Eidnes via Unbound-users]

Hi,

I'm running unbound 1.5.4 on NetBSD/amd64 7.0, and I notice that
despite me having configured

server:
  num-threads: 12

only one of the threads is handling all the queries, according to
the output from "unbound-control stats".  "Not what I wanted."

I've also configured

  so-reuseport: yes

as the comment in the template config file just preceding that is

  # use SO_REUSEPORT to distribute queries over threads.

Any ideas about where I should start looking for what's amiss?

Regards,

- Håvard