[Mauiusers] ppn=2 specification ignored

[Georg Hager]

> When a job specifies -l nodes=X:ppn=2, it sometimes happens that
> nodes on our dual-Xeon cluster are not scheduled as a whole,
> but that MAUI uses single CPUs (half nodes), as if the user had
> used ppn=1. This is a rare case, but it happens from time to time.

I have gathered some more information on this. Here is the Maui log
snippet for a job that had specified nodes=4:ppn=2 but for which Maui
decided to schedule three full nodes plus two single CPUs:

01/13 08:39:06 INFO:     processing node request line '4:ppn=2'
01/13 08:39:06 INFO:     job '55718' loaded:   1   mpt103     mpt1  86400       Idle   0 1105601945   [NONE] [NONE] [NONE] >=      0 >=      0 [NONE] 1105601946
01/13 08:39:06 INFO:     59 PBS jobs detected on RM base
01/13 08:39:06 INFO:     jobs detected: 59
01/13 08:39:06 INFO:     total jobs selected (ALL): 1/59 [State: 58]
01/13 08:39:06 INFO:     total jobs selected (ALL): 1/59 [State: 58]
01/13 08:39:06 INFO:     total jobs selected in partition ALL: 1/1 
01/13 08:39:06 MQueueScheduleRJobs(Q)
01/13 08:39:06 INFO:     total jobs selected in partition ALL: 1/1 
01/13 08:39:06 INFO:     total jobs selected in partition DEFAULT: 1/1 
01/13 08:39:06 MQueueScheduleIJobs(Q,DEFAULT)
01/13 08:39:06 INFO:     296 feasible tasks found for job 55718:0 in partition DEFAULT (8 Needed)
01/13 08:39:06 INFO:     tasks located for job 55718:  8 of 8 required (13 feasible)
01/13 08:39:06 MJobStart(55718)
01/13 08:39:06 MRMJobStart(55718,Msg,SC)
01/13 08:39:06 MPBSJobStart(55718,base,Msg,SC)
01/13 08:39:06 MPBSJobModify(55718,Resource_List,Resource,snode033:ppn=2+snode031:ppn=2+snode030:ppn=2+snode027+snode016)
01/13 08:39:06 MPBSJobModify(55718,Resource_List,Resource,4:ppn=2)
01/13 08:39:06 WARNING:  cannot set job '55718.sserver01' attr 'Resource_List:neednodes' to '4:ppn=2' (rc: 15015 'Cannot modify attribute while job running  Resource_List.neednodes')
01/13 08:39:06 INFO:     job '55718' successfully started
01/13 08:39:06 INFO:     starting job '55718'
01/13 08:39:06 INFO:     1 jobs started on iteration 135

So Maui gets the correct '4:ppn=2' spec, but ignores (?) it...

Can anyone help with this? 

Thanks,
Georg.

-- 
Georg Hager               | Email: 
Regionales Rechenzentrum  |    Georg.Hager at rrze.uni-erlangen.de
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