Hi Marcus, Thanks for the clarification - I'd actually missed the 'SMT' in subject.
Marcus Wagner <wag...@itc.rwth-aachen.de> writes: > Hi Loris, > > CPU is the smallest schedulable unit, in case of SMT its threads. Would it be reasonable to say it's *always* threads and with HT you just have twice as many as without? Having said that, it seems a little strange to say a CPU *is* a thread, as that blurs the distinction between hardware and executing software somewhat. > At the moment we have HT disabled on our systems, therefore CPU is equal to > the > cores for us. But with HT enabled, CPU is double that large (at least form > slurm > 18.08). We also have HT disabled, so I had slightly forgotten about it. It is rather annoying that the Slurm terminology is so inconsistent as it is potentially confusing for users. Cheers, Loris > Best > Marcus > > On 3/4/20 10:33 AM, Loris Bennett wrote: >> Hi Alexander, >> >> Alexander Grund <alexander.gr...@tu-dresden.de> writes: >> >>> Hi, >>> >>> we have a Power9 partition with 44 processors having 4 cores each >>> totaling 176. >>> >>> `scontrol show node <node>` shows "CoresPerSocket=22" and "CPUTot=176" >>> which confuses me. Especially as `whypending` reports e.g. "172 cores >>> free: 1" >> What's 'whypending'? >> >>> So what are "CPUs" and what are "Cores" to SLURM? Why does it mix up those >>> 2? >> This is just historical as far as I can tell. I think 'CPU' almost >> always means 'core'. >> >>> Most importantly: Does this mean `--cpus-per-task` can be as high as >>> 176 on this node and `--mem-per-cpu` can be up to the reported >>> "RealMemory"/176? >> Yes. >> >> Cheers, >> >> Loris >> -- Dr. Loris Bennett (Mr.) ZEDAT, Freie Universität Berlin Email loris.benn...@fu-berlin.de
