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From: Ralph Castain (rhc_at_[hidden])
Date: 2006-12-11 19:41:18


Hi Chris

Okay, we have modified the pernode behavior as you requested (on the trunk
as of r12821)- give it a shot and see if that does it. I have not yet added
the npernode option, but hope to get that soon.

I have a question for you about the npernode option. I am assuming that you
want n procs/node, but that you want it mapped by NODE. For example, proc 0
goes on the first node, proc 1 goes on the second node, etc. until I get one
on each node; then I wrap back to the beginning and do this again until I
get the specified number of procs on each node.

Correct?
Ralph

>Ralph,

>I agree with what you stated in points 1-4. That is what we are looking
>for.
>I understand your point now about the non-MPI users too. :-)
>
>Thanks,
>-cdm

>>-----Original Message-----
>>From: users-bounces_at_[hidden] [mailto:users-bounces_at_[hidden]] On
>>Behalf Of Ralph Castain
>>Sent: Wednesday, November 29, 2006 8:01 AM
>>To: Open MPI Users
>>Subject: Re: [OMPI users] Pernode request
>>
>>Hi Chris
>>
>>Thanks for the patience and the clarification - much appreciated. In
>>fact, I have someone that needs to learn more about the code base, so I
>>think I will assign this to him. At the least, he will have to learn a
>>lot more about the mapper!
>>
>>I have no problem with modifying the pernode behavior to deal with the
>>case of someone specifying -np as you describe. It would be relatively
>>easy to check. As I understand it, you want the behavior to be:
>>
>>1. if no -np is specified, launch one proc/node across entire allocation
>>
>>2. if -np n is specified AND n is less than the number of allocated
>>nodes, then launch one proc/node up to the specified number. Of course,
>>this is identical to just doing -np n -bynode, but that's immaterial.
>>;-)
>>
>>3. if -np n is specified AND n is greater than the number of allocated
>>nodes, error message and exit
>>
>>4. add a -npernode n option that launches n procs/node, subject to the
>>same tests above.
>>
>>Can you confirm?
>>
>>Finally, I think you misunderstood my comment about the MPI folks. Our
>>non-MPI users couldn't care less about commonality of command line
>>arguments across MPI implementations. Hence, I leave issues in that area
>>to the MPI members of the team - they are the ones that decide how to
>>deal with the myriad of different option syntaxes in the MPI community.
>>
>>Gives me too much of a headache! :-)
>>
>>Ralph