[slurm-users] Job allocating more CPUs than requested

[Chris Samuel]

On Saturday, 22 September 2018 2:35:34 PM AEST Ryan Novosielski wrote:

> We constrain using cgroups, and occasionally someone will request 1
> core (-n1 -c1) and then run something that asks for way more
> cores/threads, or that tries to use the whole machine. They won't
> succeed obviously. Is this any sort of problem?

At that point as all their processes will be contesting a particular core.  
Load average is just about what's trying to run but can't - and in this case 
it doesn't have a relationship to how difficult it can be for other jobs to do 
things because of the core restriction.

I guess it's possible the next level caches might get a work out, but then 
unless you're restricting OS daemon processes to cores that are not used by 
Slurm then you're probably still going to get some amount of cache pollution 
anyway.

All the best!
Chris
-- 
 Chris Samuel  :  http://www.csamuel.org/  :  Melbourne, VIC