[mvapich-discuss] MPI_Comm_spawn always uses just 1 host

[Jonathan Perkins]

On Mon, Feb 13, 2012 at 8:45 AM, Rutger Hofman <rutger at cs.vu.nl> wrote:
> On 02/13/2012 02:06 PM, Rutger Hofman wrote:
>> On 02/12/2012 05:42 PM, Jonathan Perkins wrote:
>>> On Sat, Feb 11, 2012 at 10:15 AM, Rutger Hofman<rutger at cs.vu.nl> wrote:
>>>> On 02/10/2012 11:26 PM, Jonathan Perkins wrote:
>>>>> Hello, in order to control which processes are spawned on which hosts
>>>>> you can modify your hostfile.
>>>>>
>>>>> In your mpirun_rsh invocation I see that you start out with 3
>>>>> processes.
>>>>> If your hostfile contains
>>>>>
>>>>> nodeA
>>>>> nodeB
>>>>> nodeC
>>>>> nodeD
>>>>> nodeE
>>>>>
>>>>> then the first spawned process will be on nodeD and the next spawned
>>>>> process will be on nodeE. Let me know if this helps.
>>>>>
>>>>
>>>> Thanks, this is what I had figured out too.
>>
>> Sorry, I must correct this. What I see is that *all* spawned processes
>> run on nodeD, even from multiple subsequent MPI_Comm_spawn() calls. So,
>> what else can I do to create processes on machines where I want them?
>> Would MPI_Comm_accept/connect work over Infiniband?
>
>
> One more note. I try mpiexec.hydra and it behaves as you describe.

Thanks for the updates.  It sounds like you may have discovered a bug
in mpirun_rsh.  I'll try to reproduce this behavior and see if we can
fix this in an upcoming mvapich2 release.

-- 
Jonathan Perkins
http://www.cse.ohio-state.edu/~perkinjo