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From: Brock Palen (brockp_at_[hidden])
Date: 2006-07-14 10:58:46

On Jul 14, 2006, at 10:40 AM, Michael Kluskens wrote:

> I've looked through the documentation but I haven't found the
> discussion about what each BTL device is, for example, I have:
> MCA btl: self (MCA v1.0, API v1.0, Component v1.2)
> MCA btl: sm (MCA v1.0, API v1.0, Component v1.2)
> MCA btl: tcp (MCA v1.0, API v1.0, Component v1.0)
> I found a PDF presentation that describes a few:
> • tcp - TCP/IP
> • openib – Infiniband OpenIB Stack
> • gm/mx- Myrinet GM/MX
> • mvapi - Infiniband Mellanox Verbs
> • sm - Shared Memory
> Are there any others I may see when interacting with other people's
> computers?

These will be the most common. I don't know OMPI plans to support
other networks like quadrics in the future or not.
> I assume that if a machine has Myrinet and I don't see MCA btl: gm or
> MCA btl: mx then I have to explain the problem to the sysadm's.

Yes, did you build OMPI your self or is this a system wide install?
If you installed it your self you need to find ware the gm or mx libs
are stored and run ./configure with the --with-gm=/path/to/gm or --
On our Mac cluster the gm libs are in /opt/gm/lib but you only need
to do ./configure --with-gm=/opt/gm --other-options

Hope that helps

Brock Palen
Center for Advanced Computing

> The second question is should I see both gm & mx, or only one or the
> other.

You only need one of them. We have only used GM as our older
hardware does not support MX, but if i understand correctly if you
can use MX use it. Maybe someone who has tested both will chime in?

> Michael
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