[slurm-users] Job allocating more CPUs than requested
chris at csamuel.org
Sat Sep 22 19:30:48 MDT 2018
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
All the best!
Chris Samuel : http://www.csamuel.org/ : Melbourne, VIC
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