HPC Monthly Call -- 2019-09-29
===

###### tags: `HPC`

:::info
- **Date:** September 29th, 2020
- **Agenda**
1. Spindle
- **Participants:**
- Valentin Churavy
- Simon Byrne
- Elliot Saba
- Todd Gamblin
- Bart Janssens
- Jake Bolewski
- Mose Giordano
- Albert Reuther
- Charlie Kawczynski
- Chris Hill

- [Previous notes](/@juliaparallel/2019-09-03)
- [Next notes](/@juliaparallel/2019-10-27)
:::

## Notes

1. Spindle
- `JULIA_DEBUG=loading` — relocating `.ji` files
- Skip timecheck to avoid hitting HD for files https://github.com/JuliaLang/julia/blob/73413fc2b279b88ca79f298e68d2789497c3ddec/base/loading.jl#L1465

2. MPIABIWrapper
3. Segway into rpath on Windows
- Wrapper executable
- Zero dependencies
- Manually dlopen the world
- Code is in master Julia
4. Action item: Review Julia spack recipe
5. Extensible _jll
- Preferences.jl to force system artifacts
6. Overrides.toml
- Maps prefixes
- Issue with `lib64`/`lib`

7. Spack
- Merged prefix
- concretization=together
8. https://github.com/JuliaPackaging/Spack.jl
9. Variants mapping
- Julia resolver only knows about versions
- _jll packages choose the “variant” they download e.g. i686-linux-musl
- Can we use Preferences to encode tags/variants?
10. Testing example:
- HDF5
- Oceananigans.jl
- Trillinos.jl
- Petsc.jl