[torqueusers] Curious question

Fernando Campos fernando.campos at uam.es
Tue Mar 30 10:35:27 MDT 2010


Hi all!!

I'm running a TORQUE cluster with "pbs_sched" scheduler. Which is the policy
for node allocation?? Can you define it anywhere on Torque?? Is this case
depending on the nodes order in "nodes" file? Should I then put the better
performance nodes at the beggining?

Thanks!

Fer.



On Tue, Mar 30, 2010 at 16:54, Charles Johnson <
charles.johnson at accre.vanderbilt.edu> wrote:

> On Mar 30, 2010, at 9:40 AM, Ken Nielson wrote:
>
> > Glen Beane wrote:
> >>
> >>
> >> On Tue, Mar 30, 2010 at 10:07 AM, Glen Beane <glen.beane at gmail.com<mailto:
> glen.beane at gmail.com
> >> >> wrote:
> >>
> >>
> >>
> >>    On Tue, Mar 30, 2010 at 9:55 AM, Charles Johnson
> >>    <charles.johnson at accre.vanderbilt.edu
> >>    <mailto:charles.johnson at accre.vanderbilt.edu>> wrote:
> >>
> >>        About the nodes file ... I have always been under the
> >>        impression that
> >>        the nodes file gives an ordering to nodes selected for jobs,
> >> i.e.,
> >>        nodes at the top of the list are considered before nodes at
> >> the
> >>        bottom. We are currently in a down time for refreshing
> >>        hardware, and
> >>        the whole cluster is quiescent. As a test of hardware we
> >>        submitted a
> >>        single job suitable for any one of several hundred nodes at
> >>        the top of
> >>        the nodes file. The job ran on a node roughly halfway down the
> >>        nodes
> >>        file. Again, there were no other jobs on the cluster.
> >>
> >>        I am curious as to why? Any ideas?
> >>
> >>        We are using torque 2.4.5 and moab 5.3.6
> >>
> >>
> >>
> >>    This is really a Moab question since Moab selects the node that
> >>    the job will run on, it has nothing to do with the order of the
> >>    nodes in the TORQUE node file. I think the default for Moab might
> >>    be "last fit", so as it scans the available nodes it will select
> >>    the last one it finds that satisfies the requirements for the
> >>    job.  There is a "first fit" and "best fit" option if I remember
> >>    correctly.
> >>
> >>    With the fifo scheduler, then yes, I think the job would run on
> >>    the first available node in the node list.
> >>
> >>
> >> actually, I was thinking of LASTAVAILABLE, not "last fit", so the
> >> definition would be different than what I stated.  This is the
> >> correct definition: "This algorithm is a best fit in time algorithm
> >> that minimizes the impact of reservation based node-time
> >> fragmentation."  I think this might be the default, but I don't
> >> remember for sure.
> >> ------------------------------------------------------------------------
> >>
> >> _______________________________________________
> >> torqueusers mailing list
> >> torqueusers at supercluster.org
> >> http://www.supercluster.org/mailman/listinfo/torqueusers
> >>
> > If you were to run TORQUE without a scheduler and started the job
> > manually TORQUE will choose the last node in the nodes file to run on.
> >
> > Ken Nielson
> > Adaptive Computing
>
>
> Thanks to all who replied. Clarity reigns. :)
>
> ~Cheers--
>
> Charles
> --
> Charles Johnson
> Advanced Computing Center for Research and Education
> Office: 615-343-2776
> Cell: 615-478-5743
> _______________________________________________
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>
>


-- 
---------------------------------------------------------------------------------------------------------
Fernando Campos Del Pozo
Departamento de Física Teórica
Facultad de Ciencias / Módulo 15 (C-XI) / Despacho 512
Universidad Autónoma de Madrid
Tlf.: +34-914974893
e-mail: fernando.campos at uam.es
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