[Mauiusers] node allocation issue

Abhishek Gupta abhig at princeton.edu
Thu Dec 2 10:35:04 MST 2010


Hi Jeff,
Yes I did verified that multiple jobs are running on same logical cpu.
Thanks,
Abhi.

Jeff Anderson-Lee wrote:
> On 12/2/2010 9:07 AM, Abhishek Gupta wrote:
>> Our job scheduler is acting little weird. The jobs submitted are going
>> on only a few nodes and each node is running more jobs than the total
>> number of CPUs on that node. We have not changed anything recently.
>> Can anyone suggest what is the best node allocation policy that make
>> sure we do not run more jobs than number of cores available on a node
>> and jobs are evenly distributed on all the nodes and not on the few 
>> nodes?
>> Thanks,
>> Abhi.
>
> We find that many users understate the number of cores/procs needed in 
> their requests.  They ask for a single cpu, then spawn multiple tasks, 
> or run Java in a way that runs two or more active threads instead of 
> one.  Maui does not seem to set any cpu affinity to prevent 
> interference nor enforce the requested number of cores as far as I know.
>
> Do you know for certain that you are getting multiple jobs allocated 
> to the same logical cpu and not just user task forks?
>
> If you use Torque as your underlying scheduler, the following should 
> help you to find true duplicate assignments:
>
> qstat -f | grep exec | sort | uniq -c | sort -n
>
> Jeff Anderson-Lee


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