Re: [OMPI devel] Q: Using a hostfile in managed environment?

[Thomas Naughton]

Hi Ralph,

OK, that's pretty much what I thought but wanted to get a sanity check. :-)
I'll see if I can reproduce the issue in a more precise manner and open an
issue if I find something off in the mapping.

Thanks,
--tjn

 _
  Thomas Naughton  naught...@ornl.gov
  Research Associate   (865) 576-4184


On Fri, 24 Feb 2017, r...@open-mpi.org wrote:




On Feb 24, 2017, at 11:57 AM, Thomas Naughton  wrote:

Hi,

We're trying to track down some curious behavior and decided to take a step
back and check a base assumption.

When running within a managed environment (job allocation):

   Q: Should you be able to use `--hostfile` or `--host` options to
  operate on a subset of the resources in the allocation?
  (Example: within 4 node SLURM allocation, run on just 2 nodes in
   allocation.)


Yes - those options are used to “filter” the allocation prior to launch



   Q: Additionally, should this be the same when launching the DVM in
  order to run on a subset of resources using subsequent
  'mpirun --hnp ...' commands?
  (Only 'orte-dvm' would need to have `--hostfile` or `--host` args.)


Yes - only the DVM needs to know the filter. When operating with a DVM, “mpirun 
--hnp...” only packages up the cmd line and sends it to the DVM. All the 
mapping occurs in orte-dvm.



There are a variety of interactions with ess/ras/rmaps and the resource
manager, but the thought was that you "should" be able to use a hostfile to
operate on a subset of the allocation. Is that a flawed assumption?

Thanks,
--tjn

_
 Thomas Naughton  naught...@ornl.gov
 Research Associate   (865) 576-4184

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Re: [OMPI devel] Q: Using a hostfile in managed environment?

[r...@open-mpi.org]

> On Feb 24, 2017, at 11:57 AM, Thomas Naughton  wrote:
> 
> Hi,
> 
> We're trying to track down some curious behavior and decided to take a step
> back and check a base assumption.
> 
> When running within a managed environment (job allocation):
> 
>Q: Should you be able to use `--hostfile` or `--host` options to
>   operate on a subset of the resources in the allocation?
>   (Example: within 4 node SLURM allocation, run on just 2 nodes in
>allocation.)

Yes - those options are used to “filter” the allocation prior to launch

> 
>Q: Additionally, should this be the same when launching the DVM in
>   order to run on a subset of resources using subsequent
>   'mpirun --hnp ...' commands?
>   (Only 'orte-dvm' would need to have `--hostfile` or `--host` args.)

Yes - only the DVM needs to know the filter. When operating with a DVM, “mpirun 
--hnp...” only packages up the cmd line and sends it to the DVM. All the 
mapping occurs in orte-dvm.

> 
> There are a variety of interactions with ess/ras/rmaps and the resource
> manager, but the thought was that you "should" be able to use a hostfile to
> operate on a subset of the allocation. Is that a flawed assumption?
> 
> Thanks,
> --tjn
> 
> _
>  Thomas Naughton  naught...@ornl.gov
>  Research Associate   (865) 576-4184
> 
> ___
> devel mailing list
> devel@lists.open-mpi.org
> https://rfd.newmexicoconsortium.org/mailman/listinfo/devel

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[OMPI devel] Q: Using a hostfile in managed environment?

[Thomas Naughton]

Hi,

We're trying to track down some curious behavior and decided to take a step
back and check a base assumption.

When running within a managed environment (job allocation):

Q: Should you be able to use `--hostfile` or `--host` options to
   operate on a subset of the resources in the allocation?
   (Example: within 4 node SLURM allocation, run on just 2 nodes in
allocation.)

Q: Additionally, should this be the same when launching the DVM in
   order to run on a subset of resources using subsequent
   'mpirun --hnp ...' commands?
   (Only 'orte-dvm' would need to have `--hostfile` or `--host` args.)

There are a variety of interactions with ess/ras/rmaps and the resource
manager, but the thought was that you "should" be able to use a hostfile to
operate on a subset of the allocation. Is that a flawed assumption?

Thanks,
--tjn

 _
  Thomas Naughton  naught...@ornl.gov
  Research Associate   (865) 576-4184

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