[slurm-users] Meaning of --cpus-per-task and --mem-per-cpu when SMT processors are used

[Alexander Grund]

Hi,










Thanks a lot,
Alexander Grund

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Alexander Grund
Interdisziplinäre Anwendungsunterstützung und Koordination (IAK)

Technische Universität Dresden
Zentrum für Informationsdienste und Hochleistungsrechnen (ZIH)
Würzburger Str.35/Chemnitzer Str.50, Raum 010 01062 Dresden
Tel.: +49 (351) 463-35982
E-Mail: alexander.gr...@tu-dresden.de
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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" 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?

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