[torqueusers] Question about what does PBS_NUM_NODES and PBS_NUM_PPN means

David Beer dbeer at adaptivecomputing.com
Tue Dec 7 09:41:46 MST 2010

> This kind of limits the usefulness of this information... A user can
> get more accurate information by parsing the nodefile, but if we
> wanted to make this information easier to get why not put it in a
> file? One line per node allocated, the format could be something
> like:
> so for a job that requested nodes=4:ppn=16 you would end up with a
> file like this:
> 0:16
> 1:16
> 2:16
> 3:16
> then we just set a environment variable that points to the location of
> this file.
> However, this idea probably has a few problems as well -- I still
> think it is better than a static ENV variable. I think in the future
> there might be a concept of a dynamically sized job that can
> grow/shrink, in that case at least the pbs_mom can rewrite the file,
> but there might be a better way to convey that information.
> This is the type of change that should be discussed by the TORQUE
> community before they are made -- the approach clearly has
> limitations, perhaps we could have come up with a better solution by
> just spending a little time talking about it first.

This wasn't really designed to be a widely-used feature to make things easier - it was a quick solution to a specific site's use case. It took about 30 minutes to implement in TORQUE, and it doesn't affect anyone who doesn't want to use it. If there is a need to make the $PBS_NODEFILE information more accessible, then that is a different discussion. This is just an easy solution for a customer.

David Beer 
Direct Line: 801-717-3386 | Fax: 801-717-3738
     Adaptive Computing
     1656 S. East Bay Blvd. Suite #300
     Provo, UT 84606

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