On 1 September 2016 at 18:16, Christof Koehler < [email protected]> wrote:
> Hello, > > On Wed, Aug 31, 2016 at 05:52:48PM -0700, Lachlan Musicman wrote: > > I don't believe it's 100% necessary to use OverSubscribe Yes. > > > > We have > > > > select/cons_res and CR_CPU, on nodes that look like > > > > NodeName=stpr-res-compute[01-02] CPUs=40 RealMemory=385000 Sockets=2 > > CoresPerSocket=10 ThreadsPerCore=2 State=UNKNOWN > OK, I will keep this in mind. > > > > > The CPUs aren't shared, but there's 40 of them per node, so that doesn't > > really matter so much. > I do not understand this. What part of a node is shared if not its > processing resource ? Or may be there is a misunderstanding because my > question was not well formulated. So I will rephrase it: > > What we are interested in is a situation where of 40 CPUs to one user 10 > are allocated and the remaining 30 to for example one other user. So no > actual oversubscription of CPUs but a sharing of the nodes CPUs between > different users which get their exclusive cpusets. It has 40 CPUs as > GRES and up to 40 can be allocated as exlusive resources to different > users. I think cgroups would provide the necessary controls for this. > > Ok, I can't speak to GRES or cgroups - we have a simple set up. In *my* explanation, a "node" is a "motherboard". IE, each motherboard has 40 cpus, and those cpus can be shared as you would like them to be (10 to one user, 30 to the other; or even 1 to 40 users, or 4 to 10 users). > Now, the point we are not sure about is what happens if a user allocates > 10 out of 40 and sets "--exclusive" (if possible). Is the usage of that > user (job) actually computed with 40 CPUs as most people would expect ? > As described before other systems appear to bill only 10 while 40 are in > fact used up. > > > > > Also, have you found this page? http://slurm.schedmd.com/mc_support.html > > That is certainly a very useful resource explaining the different > concepts and how they relate to the terminology used by slurm. However, > skimming through it there does not appear to be a direct connection to > out usage computation question. > > Cheers L. ------ The most dangerous phrase in the language is, "We've always done it this way." - Grace Hopper
