BwUniCluster2.0/FAQ - broadwell partition

FAQs concerning best practice of bwUniCluster broadwell partition (aka "extension" partition).

Login

Are there separate login nodes for the bwUniCluster broadwell partition?

• Yes, but primarily to be used for compiling code.

How to login to broadwell login nodes?

• You can directly login on broadwell partition login nodes using

$ ssh username@uc1e.scc.kit.edu

• If you are compiling code on broadwell login nodes, your code will not optimally run on the new "Cascade Lake" nodes.

Compilation

How to compile code on broadwell (extension) nodes?

On uc1 (old) login nodes:

$ icc/ifort -axCORE-AVX2 [-further_options]

To use the code only on the partition multiple_e:

$ icc/ifort -xHost [-further_options]

How to compile code to be used on ALL partitions?

On uc1e (= extension) login nodes:

$ icc/ifort -xCORE-AVX2 -axCORE-AVX512 [-further_options]

What happens with code compiled for old partition whic is running on the extension partition?

Code will run but significantly slower since AVX2 will not be used. Please recompile your code accordingly.

Job execution

How to submit jobs to the broadwell (= extension) partition

The submitted job will be distributed either way to the broadwell nodes if specified correctly, i.e.:

$ sbatch -p multiple_e

Can I use my old multinode job script for the new broadwell partition?

Yes, but please note that all broadwell nodes do have 28 cores per node.

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