[Mauiusers] Maui allocation problems.

Bill Wichser bill at Princeton.EDU
Thu Dec 27 07:28:44 MST 2007


Linux cluster
Torque 2.1.6
Maui 3.2.6p17

Problem:  #PBS -l nodes=124:ppn=1+66:ppn=2 doesn't work as I'd like it to.

The setup:
Maui is setup to alloacate in a worstfit way to spread jobs across nodes 
based on a JOBCOUNT priority.

NODEALLOCATIONPOLICY PRIORITY
NODECFG[DEFAULT] PRIORITYF='-10 * JOBCOUNT'
NODESETPRIORITYTYPE WORSTFIT

It is also set up to allocate as the user specifies:
JOBNODEMATCHPOLICY      EXACTNODE

This all works as expected.

The problem is that these single core jobs end up filling up initially 
empty nodes instead of being allocated across nodes with only 1 job 
running, which is the desired allocation.  What appears to be happening 
is that PBS sends the list of nodes to maui which then takes this static 
view of things and starts allocating.  Since there are empty nodes and 
nodes with 1 core being used, those empty nodes always get filled with 
theses single core requests instead of being allocated to a node with 
one core being used.  What winds up happening is that the empty nodes 
gets filled completely (all 4 cores) while these initially almost empty 
nodes never get another core allocated.  What I expected to happen was 
that as the nodes are being allocated to jobs, their job count would 
change and thus some of these already allocated nodes would also join in 
this allocation pool as their jobcounts would now be equal.  And in all 
cases, before a third core would be used on one of these initially empty 
nodes, a second core would be used on these other nodes.

Is this possible in any way?

Thanks,
Bill


More information about the mauiusers mailing list