[torqueusers] Fwd: ncpus anyone?

Gareth.Williams at csiro.au Gareth.Williams at csiro.au
Tue Mar 2 19:32:22 MST 2010

> -----Original Message-----
> From: David Beer [mailto:dbeer at adaptivecomputing.com] 
> Sent: Wednesday, 3 March 2010 4:53 AM
> To: torqueusers
> Subject: [torqueusers] Fwd: ncpus anyone?
> Just to let everyone know, the qstat -a output has been 
> changed to read both the value stored in nodes and ncpus, 
> using nodes when both are specified.
> > Changing the code so that qstat -a displays correctly the number of 
> > tasks with -lnodes=1:ppn=32 would be great. Then, you could 
> also make
> > 
> > sure that -lncpus=32 is a complete synonymous of -lnodes=1:ppn=32.
> Is this the behavior that everyone expects/hopes for? If so, 
> we can look at working on it. At the same time, TORQUE 3.0 is 
> likely to include much superior specification for how we are 
> requesting resources, which may end up including ncpus and 
> may not. We're looking to remove a lot of ambiguity and 
> enhance capability. By the way. we're still open to input as 
> to how all that will work, but maybe we'll send out some 
> ideas shortly if nobody has any input yet.
> Cheers,
> David

Hi David,

I agree that ncpus=X should be completely synonymous with nodes=1:ppn=X - that would make it worth keeping ncpus.  This would be complementary to specifying procs (meaning a given core count on any available hosts), and provide a more intuitive way of describing SMP jobs. In principle you could change the names nodes-ppn/ncpus/procs but in practise that would be a major pain for everybody.

BTW. I realised far later than I'd like that specifying both ncpus and nodes conflicts but does not give an error.  We had set a queue default resource nodes=1 (we no longer do so) which confounded me understanding the issue.

I think it would be good if torque would give errors if you specify more than one of nodes, ncpus or procs, as the specifications clearly conflict.  Silently choosing one (nodes - yet keeping info on the others) is confusing.



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