[torqueusers] Nodes dual and quad core

Prakash Velayutham prakash.velayutham at cchmc.org
Mon Feb 11 05:49:47 MST 2008


On Feb 11, 2008, at 6:04 AM, Albino Aveleda wrote:

> Hi,
>
> I have a cluster with dual and quad core processors.  Some nodes have
> two dual cores per processors and others have two quad cores per
> processors. How could I submit a job selecting number the cores?
>
> For example, the user want run the mpi program with 16 cores, if I use
> “#PBS -l nodes=2:ppn=8” only the quad cores will be use, but in this
> example I have 4 nodes with two dual cores free that they could run
> this job.
> How do I write the job for chose cores and not processors?
>
> Best regards,
> Bibo

Hi,

Which scheduler are you using? (Torque native / Maui / Moab).

I am not sure if this is completely supported in Torque, but in Maui/ 
Moab, there is a property called JOBNODEMATCHPOLICY which can be set  
(EXACTNODE, EXACTPROC).

Also, in Moab, you can request something like "qsub -lnodes=4" and  
this will only look for 4 cores.

And If you would want to get 4 cores from the same node, then you  
would use "qsub -lnodes=4,tpn=4".

Or, if you want 2 nodes with 4 cores each, you would use "qsub - 
lnodes=8,tpn=4" (here the total cores is 8, and the tasks per node is  
4, which means a total of 2 nodes). The regular syntax of "qsub - 
lnodes=2:ppn=4" would not work in Maui/Moab as in Torque.

Hope that helps.

Prakash


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