[mpich-discuss] Specifying hosts

[Dave Goodell]

On May 6, 2009, at 9:38 AM, Scott Atchley wrote:

> On May 5, 2009, at 5:21 PM, Dave Goodell wrote:
...
> I do not see any switches that would provide a mapping of ranks to  
> hosts. Have I missed it? If there is not, has there been any  
> discussion about providing one? I can imagine that it would be very  
> helpful in combination with "-l" to determine if a job aborts to  
> pinpoint the node for further investigation.

A switch like that would probably be a worthwhile option to add in  
Hydra.  I've filed a ticket for it [1].

> I guess I could just add something like this to my submit scripts:
>
> mpiexec -l -n <num_cores> hostname
>
> before running my actual application.

That might work, although I can't remember if mpd will always launch  
processes in the same order every time.  I think it will, but I don't  
recall right now.

>> Sorry for the very surprising behavior.  I believe that this gotcha  
>> is not present in our new process manager, Hydra.  If this doesn't  
>> solve your problem, let us know and we can dig in a bit deeper.
>>
>> -Dave
>
> Is Hydra in the 1.1b1 tarball? If so, I will give it a try.

Hydra is available in the 1.1b1 tarball but you might be better off  
waiting a week or so for 1.1rc1 to be released.  There are numerous  
bug fixes and improvements in the upcoming release.  Pavan could tell  
you for sure whether or not you will have any trouble with 1.1b1, I  
haven't been following the Hydra issues closely enough to say anything  
definitive about it.

-Dave

[1] https://trac.mcs.anl.gov/projects/mpich2/ticket/575