[torquedev] [torqueusers] Question about what does PBS_NUM_NODES and PBS_NUM_PPN means

Glen Beane glen.beane at gmail.com
Tue Dec 7 10:52:34 MST 2010


On Tue, Dec 7, 2010 at 11:41 AM, David Beer <dbeer at adaptivecomputing.com> wrote:
>
>>
>> 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:
>>
>> $PBS_NODENUM:ppn
>>
>> 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.


the customer isn't always right ;)

really, I don't think we should pollute the codebase with hacks for
specific customers when there may be a better more general way to do
something that will have wider use


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