quoted

Piotr says lscpu isn't available on ppc FreeBSD. I think this leaves us with two options:
1. either use sysctl with the risk that it may not return an accurate value
2. not support PPC for numa detection

What do you think?

I think point #2 is more not supporting FreeBSD on PPC for numa detection
rather than not supporting PPC generally, right? Personally, I am just in
favour of #1 for the sake of moving forward and giving us best support with
simplest code. If or when someone does hit this (FreeBSD+PPC) as a problem,
then we can work with them to find best solution for fixing it. Right now
we don't have anyone with the PPC+FreeBSD setup, so I'd rather ignore it
than implement more complicated solutions that we can't test "just in
case".

Fully agree here.  Can't expect a user app to completely resolve all 
limitations in the underlying OS.

Dave