[Swift-devel] Changing ppn on a per-application basis

[David Kelly]

Hello,

I have a user who would like to change ppn on a per-application basis. Is this possible right now? As far as I know, the only way to do this is currently is to create separate pool entries with varying ppn values.

The example he gave me is this: the cluster he is working on supports node sharing. For some applications he may want to use all available processors. For other applications, especially those which use GPUs to do the heavy lifting, he may only want 1 ppn and leave the other processors for other users. I can also envision cases where ppn may need to be adjusted based on memory requirements or possibly based on some data that isn't known until the program runs.

Mike and I were talking about this the other day. One of the ideas he suggested was adding a new value like stdout to the app definition. Something like this I'd imagine:

app (file o) cat (file i, int myppn)
{
  cat @i stdout=@o ppn=myppn;
}

>From what I can gather, the user is only interested in ppn at the moment. But it may be useful to eventually have a generic way to override all settings in sites.xml from an app function.

David