Telcon: 2015 08 27

Participants

Had a good meeting with NERSC Monday
- Took NERSC USG through Spack feature list
- Discussed remaining gaps for Cray support for Cori.
  - Most important needed features:
    - Ability to specify external dependencies (Matt is working on this already)
    - Group/umask settings for shared usage
      - NERSC also considering having a dedicated spack user for production
    - Cray compiler usage and module detection. Requirements:
      - Update the build environment to do this:
        
        fork a shell
        
        load required modules for the package.
        
        run the real install (planned for parallel builds anyway)
      - Ability to detect compilers from modules, not just paths.
- Very important to NERSC and to LLNL to be able to use externally (non-spack) installed packages.
- Follow up by working with Joaquin Correa and USG members on features above.
Ben Woodard at RedHat has done some interesting work to find ABI incompatibilities across compilers using Spack
- Looked at many gperftools versions
- Used libabigail (see this article)
- to see what ABI differences were bt/w gcc, clang, intel, pgi versions.
- Found ABI and DWARF bugs in clang's generated code.

Greg Becker working on an indexing capability for Spack install directories
- See PR #100
- DB will make commands like spack find faster
  - especially on shared filesystems where dir traversal is expensive.
- Will support concurrent spack instances and multiple users installing things at once.
- Greg is ironing out the final bits of his first Spack contribution.
From the Spack session at the 2015 Scalable Tools Workshop in Tahoe:
- elfutils
  - ABI-incompatible substitute for libelf
From Greg Lee:
- Several new packages:
  - ghostscript
  - graphviz
  - pkg-config
From Timo Bremer:
- PIDX package merged to develop

David S:
- module purge is broken on Cray; can't reconstruct environment after a purge.
  - module environment depends on unload order
  - starting with no environment and building a sane one may be difficult.
  - suggest: have users specify what they want as initial environment
  - tcl modules are bad at dependencies; Lmod has good support for this.
- Cray has a programming environment "interest group"
  - Might be good people to talk to about Spack/module generation/making this work.
Jim G
- Has contacts at Cray who might know the programming environment
David S
- Admins at LANL becoming more interested in Cray environment
- want someone to know "should we install this RPM from the next PE update"
  - no one knows if it'll integrate.
Mike Collette has spack create issue
- "works if you do it right, but if you do it wrong it has some weird thing I didn't understand"
- Spack wasn't understanding file URLs.
  - not enough slashes?
  - may have issue with protocol-less paths or with file:/// URLs.
Jim G:
- How to find compilers on a new machine?
  - use spack compiler add
  - May need to load module when building