[Mauiusers] RE: maximizing processor use

Sarah Mulholland smm at rincon.com
Thu Mar 5 10:21:07 MST 2009

I never saw my message get posted, but I thought I'd send a follow up for when it does come through in case anybody else has a similar issue.

We solved the problem by setting


The nodes with the fewest jobs on them are selected first.  Our node utilization went way up.


Sent: Wednesday, March 04, 2009 10:48 AM
To: 'mauiusers at supercluster.org'
Subject: maximizing processor use


I am running the maui scheduler 3.2.6 patch level 16 with torque 2.1.6.  It seems like resources aren't being used as efficiently as we would like.

In our maui.cfg, we set several quality of service levels, but I think our issue has to do with a requirement that each job only uses one processor per node.  To meet this requirement, we set JOBNODEMATCHPOLICY to EXACTNODE.

To illustrate what I think I'm seeing, I'd like to give an example of 5 nodes with two processors each.  The nodes are named 1,2,3,4,5.

Example 1:
Run simultaneous jobs:
j1 requests 5 nodes, 1ppn
j2 requests 5 nodes, 1ppn
j1 gets 1,2,3,4,5
j2 gets 1,2,3,4,5
Runs great, resources (processors, nodes) are all used

Example 2:
Run simultaneous jobs:
j1 requests 3 nodes, 1ppn
j2 requests 4 nodes, 1ppn
j3 requests 3 nodes, 1ppn
j1 gets 1,2,3
j2 gets 1,2,3,4
j3 waits because available is 1 processor on node 4 and 2 on node 5 which doesn't meet EXACTNODE
3 processors are idle while j3 waits.

I seem to recall a past discussion where it was mentioned that nodes are allocated in order.  If rather than starting at the beginning of the node list when trying to allocate each time, maui picked up where it left off and wrapped through the list, we could get this result:
j1 gets 1,2,3
j2 gets 4,5,1,2
j3 gets 3,4,5
All processors and nodes in use.  No job uses two processors on the same node.  Exactly what we hope for.

Is there an attribute I can set to get this behavior?

Thanks in advance.

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