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Subject: Re: [OMPI users] I want to check our own modified Ofed stack with MPI application
From: bhimesh akula (bhimesh.akula_at_[hidden])
Date: 2011-09-06 01:10:33


Thanks for the information.I got understanding like openmpi is a library not
a tool like qperf,correct me if i am wrong.If it is a tool,explain me how to
run it.

On Fri, Sep 2, 2011 at 5:13 PM, Jeff Squyres <jsquyres_at_[hidden]> wrote:

> If I understand you correctly, it sounds like MPI -- overall -- is new to
> you.
> If that's the case, here's the 2 minute overview: MPI is communications
> middleware, typically used for parallel applications. MPI, as an API, is
> underlying-network-agnostic; hence, it can be used with TCP sockets,
> ethernet, OpenFabrics-based networks, etc., without the upper-layer
> application being aware of the differences between these networks.
> There's lots of MPI-based applications out there, including bunches of
> benchmarks and tests. You might want to get the Intel MPI Benchmarks (aka
> "IMB") and compile and run those with Open MPI over your modified OFED
> stack. The IMB are sufficiently complex, and MPI implementations themselves
> are sufficiently complex and different from each other that running IMB with
> 4 or 8 processes will exercise your OFED stack in many different ways;
> that's probably why MPI was recommended to you.
> The two big open source MPI implementations -- Open MPI and MPICH2 -- both
> come with "wrapper" compilers (mpicc, mpic++, mpf77, mpif90, ...etc.) that
> add all the relevant compiler/linker flags to the command line to
> compile/link your application. Hence, in Makefiles, you can typically
> remove all MPI-inspired references to -I, -L, and -l and just use the
> wrapper compilers. For example:
> mpicc -c foo.c
> mpicc -c bar.c
> mpicc foo.o bar.o -o my_mpi_application
> You then use "mpirun" to launch your application in parallel. For example:
> mpirun -np 8 --hostfile my_hostfile my_mpi_application
> See the mpirun(1) for more details, and the FAQ. Each MPI implementation's
> mpirun is typically different than the others (e.g., Open MPI's mpirun has
> different CLI options than MPICH2's mpirun).
> Open MPI also allows the concept of run-time customization of the
> underlying MPI processing engine via "MCA" parameters. You can pass MCA
> params via the command line, environment, or files (see the FAQ). Open MPI
> should probably pick the OpenFabrics-based transport by default on your
> machines, but just to be sure, you can force the use of the "openib" BTL
> (byte transport layer) in Open MPI thusly:
> mpirun -np 8 --hostfile my_hostfile --mca btl openib,sm,self
> my_mpi_application
> openib = OFED-based transport (for MPI procs on remote servers)
> sm = shared memory-based transport (for MPI procs on the same server)
> self = process loopback
> That should be enough to get you going; good luck.
> On Sep 2, 2011, at 7:17 AM, bhimesh akula wrote:
> > Hi ,
> >
> > We developed new OFED stack as for our requirements to our new
> product.Now it is needed to check the functionality of new OFED stack using
> MPI,used multi node setup to check this stack.But problem is we are not
> having no idea how to use OPEN-MPI tool to check our stack.I went through
> this site "",here only mentioned how to run MPI
> applications but we need our new stack has to be checked using MPI.
> >
> > As we checked our new stack using qperf tool but MPI is more recommended
> .Want to know how to run MPI as how we used qperf. we used qperf like "at
> one node running qperf as server and running qperf at other node as
> client,ran all the qperf test cases from client to see the functionality and
> performance of OFED".Like this how we can use OPEN-MPI tool to test the new
> stack.
> >
> > I think problem conveyed well,please get back to me on this as soon as
> possible.
> >
> > Thanks & regards,
> > Punya Bhimesh.
> > _______________________________________________
> > users mailing list
> > users_at_[hidden]
> >
> --
> Jeff Squyres
> jsquyres_at_[hidden]
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