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Subject: Re: [OMPI users] Open MPI Query
From: Terry Frankcombe (terry_at_[hidden])
Date: 2009-11-24 06:13:48


On Tue, 2009-11-24 at 15:55 +0530, Vivek Satpute wrote:
> Hi,
>
> I am new to Open MPI ( which is part of OFED-1.4 packege ). I have few
> basic queries about
> Open MPI :
>
> 1) I am using openmpi-1.2.8 ( it is part of OFED-1.4 ). Is has two
> examples i) hello_c ii) ring_c
> Does those examples work on Multiple machines or meant for a
> single node (i.e. localhost) ?

MPI programs are designed to work across multiple machines. That's
largely the point of MPI. They also work well as multiple processes on
a multiple-CPU machine, or combinations of the two.

> 2) Does MPI_Send() and MPI_Recv() calls send message from process on
> one machine to
> process on another machine ? If yes, then how can I achieve this ?

Take a look at what the example codes are doing. Read man mpirun. Wait
for someone here to point you to an MPI primer or tute.

> 3) Does MPI APIs are implemented on the top of Infiniband ? Does MPI
> APIs uses Infiniband
> hardware and its module for sending and receiving data ?

If you've working infiniband, and your MPI implementation (eg. OpenMPI)
is configured to use it, then yes. As your MPI is part of OFED, this is
eminently likely.