[Trilinos-Users] Epetra slow down instead of speed up on local machine (OpenMPI?)

[Bart Janssens]

On Wed, Jun 18, 2014 at 7:29 PM, Gyorgy Matyasfalvi <matyasfalvi at gmail.com>
wrote:

> On the local machine I'm using OpenMPI and OpenBLAS. On Stampede MVAPICH2
> and Intel MKL. I wonder if this could be the problem. Does anyone have
> experience with OpenMPI and Epetra? It seems to me there is a communication
> issue.
>
>
Hi Gyorgy,

Did you compile OpenBLAS without threads (i.e. set USE_THREAD = 0) ? This
is necessary when combining with MPI, since otherwise you may overload the
machine as OpenBLAS itself can spawn multiple threads.

Cheers,

Bart
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