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Subject: Re: [OMPI users] Regarding OpenMPI
From: Jeff Squyres (jsquyres_at_[hidden])
Date: 2011-06-02 06:28:16


Not directly, but your IB network will not run without a subnet manager having been run at least once.

It's been a few years since I've been an IB vendor, but whenever you bring a new IB port online (e.g., if a server reboots) it has to check in with the subnet manager before it will be brought into the active state. Most sites tend to run their IB subnet manager on one of their login nodes for the cluster and just leave it running.

On Jun 1, 2011, at 11:55 PM, Bhargava Ramu Kavati wrote:

> Hi Jeff,
> Thank you for your quick response.
> I have another query, whether OpenMPI depends on Subnet manager/Subnet administration components of OFED ? (I mean, does OpenMPI require any services from Subnet manager/Subnet administration components in OFED without which it cannot run?)
>
> Thanks & Regards,
> Ramu
>
> On Wed, Jun 1, 2011 at 6:28 PM, Jeff Squyres <jsquyres_at_[hidden]> wrote:
> On Jun 1, 2011, at 8:49 AM, Bhargava Ramu Kavati wrote:
>
> > I am trying to run MPI applications using OpenMPI in OFED Cluster (over IB). I am trying to find whether OpenMPI supports a transport interface which is based on libibverbs layer in OFED (I mean, which does not use connection manager in OFED) ?
>
> You're asking two different questions.
>
> 1. Does Open MPI use the native verbs interface in OFED?
>
> Yes.
>
> 2. Does Open MPI use one of the OFED connection managers?
>
> For IB, Open MPI can use the RDMA connection manager, but it does not have to. It defaults to not using it (instead, it exchanges IB/verbs connection data via TCP sockets).
>
> --
> Jeff Squyres
> jsquyres_at_[hidden]
> For corporate legal information go to:
> http://www.cisco.com/web/about/doing_business/legal/cri/
>
>
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-- 
Jeff Squyres
jsquyres_at_[hidden]
For corporate legal information go to:
http://www.cisco.com/web/about/doing_business/legal/cri/