Open MPI logo

Open MPI User's Mailing List Archives

  |   Home   |   Support   |   FAQ   |   all Open MPI User's mailing list

Subject: Re: [OMPI users] slowdown with infiniband and latest CentOS kernel
From: Patrick Begou (Patrick.Begou_at_[hidden])
Date: 2014-02-27 02:36:20


Bernd Dammann wrote:
> Using the workaround '--bind-to-core' does only make sense for those jobs,
> that allocate full nodes, but the majority of our jobs don't do that.
Why ?
We still use this option in OpenMPI (1.6.x, 1.7.x) with OpenFOAM and other
applications to attach each process on its core because sometimes linux move
processes and 2 process can run on the same core, slowing the application. Even
if we do not use full nodes.
'--bind-to-core' is only not applicable if you mix OpenMP and MPI as all your
threads will be binded to the same core but I do not remember that OpenFOAM does
this yet.

Patrick

-- 
===================================================================
|  Equipe M.O.S.T.         |                                      |
|  Patrick BEGOU           | mailto:Patrick.Begou_at_[hidden] |
|  LEGI                    |                                      |
|  BP 53 X                 | Tel 04 76 82 51 35                   |
|  38041 GRENOBLE CEDEX    | Fax 04 76 82 52 71                   |
===================================================================