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Subject: Re: [OMPI users] Number of Sockets used by OpenMPI
From: George Bosilca (bosilca_at_[hidden])
Date: 2009-11-15 18:53:21


Durga,

You can find the answer to your questions in http://www.netlib.org/netlib/utk/people/JackDongarra/PAPERS/scop3.pdf
.

   george.

On Nov 15, 2009, at 14:39 , Durga Choudhury wrote:

> I apologize for dragging in this conversation in a different
> direction, but I'd be very interested to know why the behavior with
> the Playstation is different from other architectures. The PS3 box has
> a single gigabit ethernet and no exapansion ports, so I'd assume it's
> behavior would be no different than, e.g. a regular PC using the TCP
> BTL. Perhaps it has something to do with the Cell BE architecture,
> then. What was the reasoning behind this decision?
>
> I am keen to know about such 'hybrid' parallel programming paradigm,
> e.g. using Cell BE or NUMA or CUDA on top of an MPI (or even a grid
> topology). I'd appreciate any pointers to any material in this
> regards.
>
> Durga
>
> On Sun, Nov 15, 2009 at 4:48 PM, George Bosilca
> <bosilca_at_[hidden]> wrote:
>> By default only one socket per peer per physical network is opened.
>> However,
>> Open MPI has the possibility to open multiple socket per peer per
>> network,
>> based on some experiments with the Playstation (where having
>> multiple socket
>> allow for more bandwidth). The MCA parameter that allows such
>> behavior is
>> btl_tcp_links.
>>
>> george.
>>
>> On Nov 13, 2009, at 17:59 , Charles Salvia wrote:
>>
>>> When using TCP, how many sockets does each process open per peer-
>>> process?
>>> Does each process open a single socket to connect to each peer-
>>> process, or
>>> does it use TWO sockets, one for sending, one for receiving?
>>>
>>> Thanks,
>>>
>>> -Charles Salvia
>>> _______________________________________________
>>> users mailing list
>>> users_at_[hidden]
>>> http://www.open-mpi.org/mailman/listinfo.cgi/users
>>
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