Jeff (and everybody else)
First of all, pardon me if this is a stupid comment; I am learning the
nuts-and-bolts of parallel programming; but my comment is as follows:
Why can't this be done *outside* openMPI, by calling Linux's processor
affinity APIs directly? I work with a blade server kind of archirecture,
where each blade has 12 CPUs. I use pthread within each blade and MPI to
talk across blades. I use the Linux system calls to attach a thread to a
specific CPU and it seems to work fine. The only drawback is: it makes the
code unportable to a different OS. But even if you implemented paffinity
within openMPI, the code will still be unportable to a different
implementation of MPI, which, as is, it is not.
Hope this helps to the original poster.
Durga
On 11/28/06, Jeff Squyres <jsquy...@cisco.com> wrote:
There is not, right now. However, this is mainly because back when I
implemented the processor affinity stuff in OMPI (well over a year
ago), no one had any opinions on exactly what interface to expose to
the use. :-)
So right now there's only this lame control:
http://www.open-mpi.org/faq/?category=tuning#using-paffinity
I am not opposed to implementing more flexible processor affinity
controls, but the Big Discussion over the past few months is exactly
how to expose it to the end user. There have been several formats
proposed (e.g., mpirun command line parameters, magic MPI attributes,
MCA parameters, etc.), but nothing that has been "good" and "right".
So here's the time to chime in -- anyone have any opinions on this?
On Nov 25, 2006, at 9:31 AM, shap...@isp.nsc.ru wrote:
> Hello,
> i cant figure out, is there a way with open-mpi to bind all
> threads on a given node to a specified subset of CPUs.
> For example, on a multi-socket multi-core machine, i want to use
> only a single core on each CPU.
> Thank You.
>
> Best Regards,
> Alexander Shaposhnikov
> _______________________________________________
> users mailing list
> us...@open-mpi.org
> http://www.open-mpi.org/mailman/listinfo.cgi/users
--
Jeff Squyres
Server Virtualization Business Unit
Cisco Systems
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