I have a slightly odd problem, that you might not think is important
at all. Anyways, here it goes:
I'm using a single eight-core machine. I want to oversubscribe four of
the cores and leave the other four idle. My approach is to make a
localhost slot=4 # shouldn't this limit the core count to 4?
and run the command:
$mpirun -np 8 --hostfile my_hostfile ./my_mpiprog
or the command:
$mpirun -np 8 --host localhost,localhost,localhost,localhost ./
Still, all eight cores are being used. I can see why you would want to
use all cores, and I can see that oversubscribing a sub-set of the
cores might seem silly. My question is, is it possible to do what I
want to do without hacking the open mpi code?
Guess I just wanted to know is there is a solution I overlooked before
I start hacking like a madman :)