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OpenMDAO / testflo

A simple python testing framework that can run unit tests under MPI (or not).
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Allow MPI to oversubscribe when running tests #41

Closed ewu63 closed 4 years ago

ewu63 commented 4 years ago

I think this is a behaviour introduced in more recent versions of OpenMPI, but by default you cannot oversubscribe MPI jobs (i.e. run with more processes than the number of processors available). To do this, you must specify --oversubscribe when calling mpirun, otherwise parallel tests that require more procs than available will fail.

To allow this with testflo I think these lines have to be modified, but I'm not sure if you want a dedicated flag, or if you want a general argument where arbitrary flags can be passed to mpirun.

naylor-b commented 4 years ago

We set the following in our environment to get around issues with newer versions of OpenMPI:

export OMPI_MCA_btl=self,tcp export OMPI_MCA_rmaps_base_oversubscribe=1

ewu63 commented 4 years ago

Ah, I tried to google MCA environment variables that would control this, but didn't figure out the right ones. Thanks.