Parallel speedup

[rfryeSigma]

I ran the catilever example in the documentation: mpiexec -np 2 ./topopt.
It ran fine, but the -np argument to mpiexec does not seem to do anything useful.
It just runs duplicate copies of the same simulation with no speedup.
Is there something I need to do to take advantage of multiple CPUs?
I am running on an Apple M1 chip.