#921: Automatic undersubscribing --------------------------+------------------------------------------------- Reporter: hinder | Owner: eschnett Type: enhancement | Status: new Priority: minor | Milestone: Component: SimFactory | Version: Resolution: | Keywords: --------------------------+-------------------------------------------------
Comment (by hinder):
(I just realised that in my test job submission on LoneStar I set the wrong --procs anyway, so my statement about what it actually does might be wrong)
I'm not sure exactly how it should be implemented. The basic user interface is quite simple: user requests a number of threads with --procs, and simfactory chooses everything so that at least this many threads get executed, rounded up to the granularity of the system. Maybe it is best to keep this model, as it is easy to explain (though, a warning that the number of threads being executed has been rounded might be useful). I think my suggestion is that if less than a node has been requested, the rounding shouldn't happen. Actually, in my case, what I'm interested in is setting the number of MPI processes. Maybe what I want is to be able to set this directly. I think that at the moment I have to set --procs 6 --ppn-used 6 to get one MPI process. This means I have to know that there are 6 threads per process. I would like to be able to say --processes 1 instead; that would solve my problem.