Build and optimise tasks before release

[manodeep]

Mostly a task list for me so I don't forget.

Build

• use upstream oasis3-mct v5.2
• check with Harshula if this patch can be added to oasis3-mct. Helps with loadbalancing analysis
• re-order the spack.yaml so that the top-level ACCESS-supported models occur first (UM7, MOM5, CICE5), then intermediate dependencies (fms, gcom4, oasis3-mct), and finally infrastructure level dependencies (netcdf, hdf5, openmpi, compiler etc)

Optimisation options

Since we need more throughput, we will switch to a 5-node config. Needs new layouts and tests with the segment sizes

• Generate and test new layouts varying UM7, MOM5 and CICE5 core counts and distribution
• Check for all combinations with segment sizes (if time permits, check for multiple different values of the segment sizes, all combinations if time really permits)

Checks for bitwise-repro

• Confirm that re-running an experiment produces bitwise identical results
• Check whether changing the ATM layout (keeping the ocean and ice fixed) preserves bitwise identical output. Might not be true if total number of ATM cores are changed (this is a change in behaviour from ESM1.5, might go away if we use -xCORE-AVX2 instead of -x86_64_v4)

[manodeep]

Update to upstream oasis3-mct v5.2 happening in here