---
# System prepended metadata

title: HPC Monthly Call -- 2019-09-29
tags: [HPC]

---

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

