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Subject: Re: [OMPI users] COMM_ACCEPT/COMM_CONNECT: what BTL will the connected processes use?
From: George Bosilca (bosilca_at_[hidden])
Date: 2009-04-21 10:48:09


With few exceptions, Open MPI will choose the best BTL. There are two
exceptions I know about:
1. sm - we didn't figure out a clean way to do it, nor we spent too
much time trying to
2. elan - the initialization of the device is a global operation, and
we cannot guarantee that all nodes are involved in the accept/connect.

   george.

On Apr 21, 2009, at 09:28 , Katz, Jacob wrote:

> Hi,
>
> In a dynamically connected client/server-style application, where
> the server uses MPI_OPEN_PORT/MPI_COMM_ACCEPT and the client uses
> MPI_COMM_CONNECT, what will be the communication method (BTL) chosen
> by OMPI? Will the communication thru the resultant inter-
> communicator use TCP, or will OMPI choose the best possible method
> (e.g. sm if the client and the server are on the same node)?
>
> Thanks.
> --------------------------------
> Jacob M. Katz | jacob.katz_at_[hidden] | Work: +972-4-865-5726 | iNet:
> (8)-465-5726
>
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