[torquedev] nodes, procs, tpn and ncpus

Garrick Staples garrick at usc.edu
Thu Jun 10 13:09:22 MDT 2010


On Thu, Jun 10, 2010 at 08:55:58PM +0200, "Mgr. Šimon Tóth" alleged:
> Semantics of stuff like -l nodes=X,procs=Y should be defined in the
> documentation, but seriously when ANYONE writes -l nodes=4, he means
> exactly what he wrote: "I want 4 nodes".

I got it.

We toss "nodes" out the window. Beat it out of the house.

We turn the whole thing around and use "procs" only.  "-l procs=X" makes
perfect sense. Everyone knows what that means, right?

*AND* "-l procs=X:ppn=Y" makes perfect sense too!  I want X processors
distributed as Y procs per node.

Noone ever actually cared about nodes anyways. They care about processors. If
your job is CPU-bound, then all you care about is how many processors you want.
If your job is IO-bound, then you care about having enough bandwidth available
to your processor.

We could even go one better and use "cores". How many cores would you like
today, sir?


 
> Btw. I still don't think that -l procs=X is a good idea. I would much
> rather see something like #packed, or #can_pack supported in the nodespec.

Something like "#packed" could be interesting, as long as we agree that packing
a job with ppn is dumb, useless, and should be considered an error.


 
> Even more great would be disjunctive nodespec support (but that goes
> into NP-complete even for determining if the nodespec can be satisfied).
> 
> "-l nodes=4:ppn=2:vmem=4G+2:ppn=4:vmem=16G|8:ppn=3:vmem=8G"

Sure. Thank you for volunteering :)

-- 
Garrick Staples, GNU/Linux HPCC SysAdmin
University of Southern California

Life is Good!
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