[slurm-users] Meaning of --cpus-per-task and --mem-per-cpu when SMT processors are used
Ole Holm Nielsen
Ole.H.Nielsen at fysik.dtu.dk
Wed Mar 4 09:31:00 UTC 2020
On 3/4/20 10:12 AM, Alexander Grund wrote:
> we have a Power9 partition with 44 processors having 4 cores each totaling
What is your hardware configuration? Do you have 1 server with 44
processor sockets, and each processor has 4 CPU cores? Or is it maybe 1
server with 1 or more sockets for a total of 44 CPU cores, and each CPU
core is running 4 hyperthreads?
I think you should give the relevant node and partition lines from your
Which Slurm version do you run?
> `scontrol show node <node>` shows "CoresPerSocket=22" and "CPUTot=176"
> which confuses me. Especially as `whypending` reports e.g. "172 cores free: 1"
The whypending tool does not appear in a google search. Where did you get
it from and what does it do?
> So what are "CPUs" and what are "Cores" to SLURM? Why does it mix up those 2?
> 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?
Perhaps this page will be of use to you:
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