[GE users] Multithreading and resource consumption

Reuti reuti at staff.uni-marburg.de
Wed Feb 21 01:12:42 GMT 2007


Am 21.02.2007 um 01:22 schrieb Bevan C. Bennett:

> Situation: We have some applications that (either by default or  
> sometimes by
> user-configuration) run multi-threaded and use up more than a  
> single CPU worth
> of computational resources.
> I figured that creating a default parallel environment seemed like  
> the correct
> answer for this, so a job known to spawn two active threads could  
> use "-pe multi
> 2" and get issued two slots, preventing it from stepping on, or  
> being stepped on
> by, other jobs on the same system.
> At first these jobs weren't running at all, claiming "no suitable  
> queues", until
> I figured out that consumables specified with "-l" appear to get  
> multiplied by
> the number of nodes requested, so "qsub -pe multi 4 -l mem=2G"  
> would look for a
> system with 4 open slots and mem=8G (2Gx4), not 4 slots and mem=2G.
> The problem has now arisen, however, that some of these  
> applications have a
> limited number of licenses available. We've been tracking the  
> licenses through
> SGE as well, but a multi-threaded "-pe multi 4" job doesn't need to  
> take up 4
> licenses (and, in fact, can't, because they don't exist). Is there  
> any way to
> over-ride this resource multiplication?
> FWIW, the job in question needs 1 "standard" and 1 "enable  
> multithreading"
> license, no matter how many threads we tell it to spawn.

for now you have to devide the license by the number of slots, i.e. - 
l standard=0.25,multithreading=0.25

-- Reuti

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