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Subject: Re: [OMPI users] Number of Sockets used by OpenMPI
From: Durga Choudhury (dpchoudh_at_[hidden])
Date: 2009-11-15 19:03:15


Thanks, George

This would be an invaluable reference to me.

Best regards
Durga

On Sun, Nov 15, 2009 at 6:53 PM, George Bosilca <bosilca_at_[hidden]> wrote:
> 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
>>>> _______________________________________________
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>>>> http://www.open-mpi.org/mailman/listinfo.cgi/users
>>>
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>>
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