Julia workers: why so many processes? what is --bind-to doing?

I just looked at my htop output after doing addprocs(3). I was surprised by couple of things:

  1. why are there so many julia processes?
  2. What are all the options at the worker processes? I did julia --help but the --bind-to and --worker options don’t show up. What do they mean?

here is htop:

If you switch into tree view you can see that a number of displayed processes are dependent processes/childs (in my case 4, but that might vary according to the number of CPUs your system has) these workers go away when I set OPENBLAS_NUM_THREADS=1 and UV_THREADPOOL_SIZE=1.