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From: Jorge Parra (jeparra_at_[hidden])
Date: 2007-10-30 12:42:06


Hi Rainer,

Thank you for your reply. Linux does not freeze. The one that freezes is
OpenMPI. Sorry for my unaccurate choice of words that led to confusion.
Therefore dmesg does not show anything abnormal (I attached to this email
a full dmesg log, captured when openmpi freezes).

When openmpi ferezes I can, from another terminal, see that the node on
which openmpi is originaly run (the local one) has two processes: orted
and mpirun. The remote node has one: orted. This seems to be normal.
However, in both nodes there are not any openmpi activity. There is only
an initial "calling init" printout in the local node (I included it in
the greetins.c program for testing purposes).

Unfortunately, I have not been able to compile openmpi 1.2.4 or any of the
1.2 trunk versions. Trunks 1.0 and 1.1 copiled well in my system. I
already opened a case for this, but I received a message that the person
it was assigned is in paternal leave. So I think I need to wait a bit for
help on that :). So I am stuck with version 1.1.5.

I am running openmpi as root because my system has some special
conditions. This is an attempt to make an embedded Massive Parallel
Processor (MPP), so the nodes are running embedded versions of linux,
where normally there is just one user (root). Since this is an isolated
system, I did not thing this could be a problem (I don't care about
security issues too).

Again, thank you for all your help,

Jorge

On Tue, 30 Oct 2007, Rainer Keller wrote:

> Hello Jorge,
> On Monday 29 October 2007 18:27, Jorge Parra wrote:
>> When running openMPI my system freezes when initializing MPI (function
>> MPI_init). This happens only when I try to run the process in multiples
>> nodes in my cluster. Running multiple instances of the testing code
>> locally (i.e ./mpirun -np 2 greetings) is succesful.
> would it be possible to repeat the tests with the latest Open MPI-1.2.4
> version?
>
> Even though nothing in Open MPI should make Your system freeze.
> Could You check the logs on the nodes and possibly have a dmesg created just
> before the MPI_Init...
>
>> - rsh runs well, and is configured to full access. (i.e. rsh
>> "192.168.1.103 date" is succesful, so they are "rsh AFRLMPPBM2 date" or
>> "rsh AFRLMPPBM2.MPPdomain.com"). Security is not an issue in this system.
>>
>> - uname -n and hostname return a valid hostname
>>
>> - The testing code (attached to this email) is run (and fails) as:
>> ./mpirun --hostfile /root/hostfile -np 2 greetings . The hostfile has the
>> names of the localnode (first entry:AFRLMPPBM1) and the remote node
>> (second entry: AFRLMPPBM2). This file is also attached to this email.
>>
>> - The environment variables seem to be properly set (see env.log attached
>> file). Local mpi programs (i.e. ./mpirun -np 2 greetings) run well.
>>
>> -.profile has the path information for both the executables and the
>> libraries
>>
>> - orted runs in the remote node, however it does not print anything in
>> console. The only output in the remote node is:
>>
>> pam_rhosts_auth[235]: user root has a `+' user entry
>> pam_rhosts_auth[235]: allowed to root_at_[hidden] as root
>> PAM_unix[235]: (rsh) session opened for user root by (uid=0)
>> in.rshd[236]: root_at_[hidden] as root: cmd='( ! [ -e
>> ./.profile ]
>>
>> || . ./.profile; orted --bootproxy 1 --name 0.0.1 --num_procs 3
> You're running as root? Why is that?
>
>> Then the remote process returns command prompt. However orted is in the
>> background. The local process is frozen, and just prints: "Calling init",
>> which is just before MPI_Init (see greetings.c).
>>
>> I believe the COMM WORLD cannot be correctly initialized. However I can't
>> see which part of my configuration is wrong.
>>
>> Any help is greatly appreciated.
>
> With best regards,
> Rainer
>