Solved Is MAKE_JOBS_NUMBER useful?

I'm looking to use all cores when compiling ports. I notice some ports build with 8 jobs, which is ideal since I have 8 cores. Some seem to build only with one (gcc9). This is with default settings, not trying to override anything (yet).

Does MAKE_JOBS_NUMBER default to the number of codes? Or can setting it help for some ports?

Thank you!
Some ports only use one "job" as they may miscompile otherwise however GCC doesn't so you're probably watching it at a stage where all jobs are waiting for a dependency to finish.
Setting MAKE_JOBS_NUMBER makes sense if you're low on memory but have many cores for instance as performance is going to hit rock bottom if your machine starts swapping, it's also a simple way of preventing ports to fire up jobs for all cores.