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Subject: Re: [OMPI users] Problems with OpenMPI running with Rmpi
From: Dirk Eddelbuettel (edd_at_[hidden])
Date: 2008-10-17 12:06:16


On 17 October 2008 at 12:42, Simone Giannerini wrote:
| Dear all,
|
| I managed to install successfully Rmpi 0.5-5 on a quad opteron machine (8
| cores overall) running on OpenSUSE 11.0 and Open MPI 1.5.2.
|
| this is what I get
|
| > library(Rmpi)
| [gauss:24207] mca: base: component_find: unable to open osc pt2pt: file not
| found (ignored)
| libibverbs: Fatal: couldn't read uverbs ABI version.
| --------------------------------------------------------------------------
| [0,0,0]: OpenIB on host gauss was unable to find any HCAs.
| Another transport will be used instead, although this may result in
| lower performance.
| --------------------------------------------------------------------------

I am surprised that your googling did lead to you stumbling on dozens of
posts on this telling you that the config file

        /etc/openmpi/openmpi-mca-params.conf (location for Debian etc)

can be changed to explicitly setting btl to 'no openib' as in

        # Disable the use of InfiniBand
        # btl = ^openib
        btl = ^openib

which will suppress the warning by suppressing the load of IB. Better still,
newer Open MPI release do this by default.

| I have searched the archives and found that the following suggestion was
| given for a similar problem:
|
| > Open MPI has Infiniband module compiled but there is no IB device found
| > on your host. Try to add "--mca btl ^openib" string to your command
| > line.

That's one way of suppressing it, but not the only one.

| Since I am not calling mpi directly but through Rmpi I do not know where to
| put that flag, I might contact the Rmpi mantainer, in any case, I would be
| grateful if you had further suggestions.

There is nothing Rmpi can do there so contacting Dr Yu, while generally a
good idea with actual Rmpi issues, is not really advised here.

Cheers, Dirk

-- 
Three out of two people have difficulties with fractions.