-2

And I run it on Linux , it can be even 200 or 1000. It really confused me. Could anyone explain that? thx!

Gilles Gouaillardet
  • 8,193
  • 11
  • 24
  • 30
Maple
  • 11
  • Welcome to Stack Overflow! Please read http://stackoverflow.com/help/mcve and edit your question accordingly. Like this, it's hard to discern what you are asking. – anothernode Apr 16 '18 at 11:34

1 Answers1

1

Long story short, your Mac likeky has one socket with two cores and two hyperthreads each.

By default, Open MPI can run up to 2 MPI tasks.

You have two options here

  • mpirun --use-hwthread-cpus ... so you can run up to 4 MPI tasks
  • mpirun --oversubscribe ... so you can run any number of MPI tasks
Gilles Gouaillardet
  • 8,193
  • 11
  • 24
  • 30