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From: Ralph H Castain (rhc_at_[hidden])
Date: 2006-12-13 09:41:38


On 12/13/06 7:33 AM, "Maestas, Christopher Daniel" <cdmaest_at_[hidden]>
wrote:

> Being consistent makes sense to me. Question though, if we set:
> ---
> OMPI_MCA_rmaps_base_schedule_policy=node
> ---
>
> Would that still map -npernode allocations on a bynode basis too? I
> think it should.

Sure! All the "-bynode" command line option does, actually, is set that mca
param... :-)

>
> What's funny is how the old mpirun w/ rsh or ssh from long ago in mpich,
> used to basically map by node mapping, and we've come to see us mapping
> byslot now. Dang those smp systems. :-)

Ja, ist definitely confusing...

>
> -cdm
>
>> -----Original Message-----
>> From: users-bounces_at_[hidden]
>> [mailto:users-bounces_at_[hidden]] On Behalf Of Ralph H Castain
>> Sent: Wednesday, December 13, 2006 6:57 AM
>> To: Open MPI Users <users_at_[hidden]>
>> Subject: Re: [OMPI users] Pernode request
>>
>>
>>
>>
>> On 12/12/06 9:18 AM, "Maestas, Christopher Daniel"
>> <cdmaest_at_[hidden]>
>> wrote:
>>
>>> Ralph,
>>>
>>> I figured I should of run an mpi program ...here's what it
>> does (seems
>>> to be by-X-slot style):
>>> ---
>>> $ /apps/x86_64/system/mpiexec-0.82/bin/mpiexec -npernode 2 mpi_hello
>>> Hello, I am node an41 with rank 0
>>> Hello, I am node an41 with rank 1
>>> Hello, I am node an39 with rank 4
>>> Hello, I am node an40 with rank 2
>>> Hello, I am node an38 with rank 6
>>> Hello, I am node an39 with rank 5
>>> Hello, I am node an38 with rank 7
>>> Hello, I am node an40 with rank 3
>>> ---
>>
>> Clearly mapping by slot here. Question: our default mapping
>> mode is by slot,
>> as this example also shows. I could turn the npernode
>> behavior around from
>> what I previously described - we could default to mapping by
>> slot (as we do
>> normally, and in concert with what mpiexec appears to be
>> doing), and let
>> users provide the "-bynode" option to change to mapping by node.
>>
>> This wouldn't have any affect on the pernode behavior since
>> that option only
>> maps one proc/node anyway (so mapping by slot or by node
>> yields the same
>> result).
>>
>> It seems to me this would be more consistent. Make sense?
>> Ralph
>>
>>
>>
>
>
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