[torqueusers] Problem with ppn and routing : Possible way to get the routing you want continued.

Ken Nielson knielson at adaptivecomputing.com
Thu Dec 2 14:33:01 MST 2010

The TORQUE "resource manager" knows nothing of ncpus. When a job is submitted and the ncpus keyword is used the string is passed through to the scheduler. In the case of PBS this would be pbs_sched. If you run torque without a scheduler and call qrun for a job you will get a single node and a single processor to run the job.

There are probably other PBS old timers who may know more. 


----- Original Message -----
From: "Glen Beane" <glen.beane at gmail.com>
To: "Torque Users Mailing List" <torqueusers at supercluster.org>
Sent: Thursday, December 2, 2010 2:26:55 PM
Subject: Re: [torqueusers] Problem with ppn and routing : Possible way to get the routing you want continued.

On Thu, Dec 2, 2010 at 1:27 PM, Ken Nielson
<knielson at adaptivecomputing.com> wrote:
> On 12/02/2010 11:06 AM, Garrick Staples wrote:
>> ncpus and nodes are competing ways to specify a resource request. Don't mix
>> them and everything works better.
>> ncpus pre-dates clusters and is used to specify the number of cpus on 1 node.
>> nodes was grafted into OpenPBS later in life to deal with clusters.
> The TORQUE resource manager has no concept of ncpus. It is interpreted
> by the scheduler. In the case of Moab it indicates the number of procs
> to be used per task.
I don't know much about how ncpus are handled, but torque must have
some kind of concept, as it predates nodes, and I don't think anyone
went through and stripped out all kinds of code related to ncpus.  I
do know that your $PBS_NODEFILE only gets one host for requests using
ncpus unless you are using something like Maui or Moab.
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