[torqueusers] processor allocation help

Martin Siegert siegert at sfu.ca
Wed Aug 15 11:16:56 MDT 2007


Hi Aaron,

On Wed, Aug 15, 2007 at 11:38:51AM -0400, Aaron Knister wrote:
> That works however my users don't possess the technical knowhow to 
> figure that out. They just want to tell the queueing system "i need 12 
> cpus anywhere. go find them". Is there a way to do this?
> 
> -Aaron
> 
> 
> David Backeberg wrote:
> >On 8/14/07, Aaron Knister <aaron at iges.org> wrote:
> >  
> >>Something still isn't right. I have two nodes with 8 processors each.
> >>qsub -l nodes=12 sits in the queue with a "Deferred" state. Any ideas?
> >>    
> >
> >Yes. You just said you have two nodes, and you asked for twelve nodes.
> >Torque decided it will hold your job until it sees you have twelve
> >nodes. That might be a while if you don't plan on buying more
> >hardware.
> >Ask for 2 nodes with six processors per node instead.
> >
> >qsub -l nodes=2:ppn=6

Actually this is the wrong answer: you want the 12p job to start
whenever there are 12 processors available regardless of their
distribution over the nodes. E.g., if there is a 4p job running
and you submit a 12p job that job should start immediately using
4p on one node and 12p on the other; -l nodes=2:ppn=6 would not
accomplish this.

The solution is to tell torque that you actually have 16 processors:

qmgr -c 'set server resources_available.nodect = 16'

After that you should be able to do what you want.

Cheers,
Martin

-- 
Martin Siegert
Head, Research Computing
WestGrid Site Lead
Academic Computing Services                phone: 778 782-4691
Simon Fraser University                    fax:   778 782-4242
Burnaby, British Columbia                  email: siegert at sfu.ca
Canada  V5A 1S6

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