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Subject: Re: [OMPI users] MPI Program hangs when runs on more than one host
From: long thai (thaithanhlong2501_at_[hidden])
Date: 2010-04-20 05:56:59


Hi Changsheng

Thank you very much for your solution. The program runs well now :)

Regards.

On Tue, Apr 20, 2010 at 3:54 PM, Changsheng Jiang <jiangzuoyan_at_[hidden]>wrote:

> I have encountered the same problem too.
>
> By gdb attached, it's show that the processes are in a loop of (e)poll.
> After configuring the network interface in ~/.openmpi/mca-params.conf using
> btl_tcp_if_include, all hosts work fine.
>
> just fyi.
> Changsheng Jiang
>
>
> On Tue, Apr 20, 2010 at 14:39, long thai <thaithanhlong2501_at_[hidden]>wrote:
>
>> Hi all.
>>
>> I'm just using OpenMPI for few days. I'll try to run a simple MPI program,
>> the program is ProcessColors which I get from CI-Tutor<http://ci-tutor.ncsa.illinois.edu/content.php?cid=1091>.
>> I have 2 hosts, if I run the program separately on each one, it runs well.
>> However, if I run it on two hosts using following command: *mpirun --host
>> host1,host2 --preload-binary -np 8 ProcessColors*. The program hangs.
>>
>> When I use command *ps -A* to check running process, I find out that
>> there is 4 processes running on each host. So, I think that there is a
>> deadlock on my program, but why it runs well with single host?
>>
>> All those following commands run without any problem on both machine:
>>
>> - mpirun -np 8 ProcessColors
>> - mpirun --host host1 -np 8 ProcessColors
>> - mpirun --host host2 -np 8 ProcessColors
>>
>> Later, I found out that the problem comes when the remote host try to send
>> message to the host which root process (process 0) is running, which is the
>> host that I run the command. I don't know why the process is blocked at
>> sending task.
>>
>> Any help from you is precious to me.
>>
>> Regards.
>>
>> Long Thai.
>>
>>
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>> users_at_[hidden]
>> http://www.open-mpi.org/mailman/listinfo.cgi/users
>>
>
>
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