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Subject: Re: [OMPI users] OpenMPI / SLURM -> Send/Recv blocking
From: Jeff Squyres (jsquyres_at_[hidden])
Date: 2012-02-02 08:09:09


Have you disabled iptables (firewalling) on your nodes?

Or, if you want to leave iptables enabled, set it such that all nodes in your cluster are allowed to open TCP connections from any port to any other port.

On Feb 2, 2012, at 4:49 AM, adrian sabou wrote:

> Hi,
>
> The only example that works is hello_c.c. All others (that use MPI_Send and MPI_Recv)(connectivity_c.c and ring_c.c) block after the first MPI_Send / MPI_Recv (although the first Send/Receive pair works well for all processes, subsequent Send/Receive pairs block). My slurm version is 2.1.0. It is also worth mentioning that all examples work when not using SLURM (launching with "mpirun -np 5 <exaple_app>"). Blocking occurs only when I try to run on multiple hosts with SLURM ("salloc -N5 mpirun <example_app>").
>
> Adrian
>
> From: Jeff Squyres <jsquyres_at_[hidden]>
> To: adrian sabou <adrian.sabou_at_[hidden]>; Open MPI Users <users_at_[hidden]>
> Sent: Wednesday, February 1, 2012 10:32 PM
> Subject: Re: [OMPI users] OpenMPI / SLURM -> Send/Recv blocking
>
> On Jan 31, 2012, at 11:16 AM, adrian sabou wrote:
>
> > Like I said, a very simple program.
> > When launching this application with SLURM (using "salloc -N2 mpirun ./<my_app>"), it hangs at the barrier.
>
> Are you able to run the MPI example programs in examples/ ?
>
> > However, it passes the barrier if I launch it without SLURM (using "mpirun -np 2 ./<my_app>"). I first noticed this problem when my application hanged if I tried to send two successive messages from a process to another. Only the first MPI_Send would work. The second MPI_Send would block indefinitely. I was wondering whether any of you have encountered a similar problem, or may have an ideea as to what is causing the Send/Receive pair to block when using SLURM. The exact output in my console is as follows:
> >
> > salloc: Granted job allocation 1138
> > Process 0 - Sending...
> > Process 1 - Receiving...
> > Process 1 - Received.
> > Process 1 - Barrier reached.
> > Process 0 - Sent.
> > Process 0 - Barrier reached.
> > (it just hangs here)
> >
> > I am new to MPI programming and to OpenMPI and would greatly appreciate any help. My OpenMPI version is 1.4.4 (although I have also tried it on 1.5.4), my SLURM version is 0.3.3-1 (slurm-llnl 2.1.0-1),
>
> I'm not sure what SLURM version that is -- my "srun --version" shows 2.2.4. 0.3.3 would be pretty ancient, no?
>
> --
> 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/