[torqueusers] forcing use of one processor per node?

Jim Coyle jjc at iastate.edu
Wed Apr 16 09:52:26 MDT 2008


John,

This is a function of the launcher.

I use mpirun and create a different machinefile.
sort -u $PBSNODEFILE > ./tmp1
cat tmp1 tmp1  > tmp2
mpirun -np 4 -machinefile tmp2 ...

I have actually written a script, mprun1, to do this for me.

If you use say fluent, you need to use the cnf= argument.

 - Jim Coyle, Phd
Research Computing Group
Iowa State Univ.

-----Original Message-----
From: torqueusers-bounces at supercluster.org
[mailto:torqueusers-bounces at supercluster.org] On Behalf Of John Young
Sent: Wednesday, April 16, 2008 10:11 AM
To: torqueusers at supercluster.org
Subject: [torqueusers] forcing use of one processor per node?

I have a small cluster of dual processor machines.  Normally,
I would like to keep each processor busy, but sometimes (due
usually to memory constraints) I would like to force a job
that I want to run, say, on 4 processors to run on 4 separate 
nodes each using only one processor, rather than on two nodes
using both processors.

I have tried using things like

#PBS -l nodes=4:ppn=1

and even 

#PBS -W x=NACCESSPOLICY:SINGLETASK

but it does not seem to matter.  I always end up using both
processors on two nodes.  'qstat -a' says that the job is
using 4 nodes, but it doesn't really...  :-(

Any ideas?

						JY
------------------------------------------------------------
John E. Young				NASA LaRC B1148/R226
Analytical Services and Materials, Inc.       (757) 864-8659
'All ideas and opinions expressed in this communication are
those of the author alone and do not necessarily reflect the
ideas and opinions of anyone else.'
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