Telcon: 2021 09 29

Attendees

• Todd Gamblin
• Peter Scheibel
• (TBD: whoever wants to discuss or add Spack issues)

Agenda

• Resolving discrepancies between spack load, module load, and spack env activate

  • See: https://github.com/spack/spack/discussions/26266
  • Discussion point: Greg pointed out that some link-type deps require env variables to be set (MY_CONFIG_FILE=/path/to/path.ini or so). This implies calling setup_run_environment on that dep. One solution is to make the dependent add a (run, link)-edge instead of just link edge, but it doesn't seem like it's the dependent's responsibility. So: should setup_run_environment be called on each transitive link type dep too (and run type deps of link type deps)? What is the difference between link/run type deps then, really? Just that only-link-type deps prefix paths aren't added to PATH?

• (Partially covered last week, TBC later) What about packages that install some other package with them (i.e. packages with vendored dependencies)

  • E.g. Mvapich2 installs hwloc with it
  • (Mark) papi vendors libperfmon (libpfm4?)
    • hpctoolkit can work with either papi or libperfmon directly
  • In Spack we typically ask if there is an option to disable the vendoring
    • What to do when it doesn't?
      • Create a patch to remove it?
  • Would it be good to allow a Spack package to describe these additional packages that "come along" with it
  • Spack-based solutions
    • Allow mvapich to provide hwloc (as a virtual)?
    • Massimiliano added a patch for the old concretizer to allow a package to add dependency specs to a concretization

• Discussion: Packages which require multiple build systems: how to handle them?

  • Discussions on this:
    • (Proposal based on using a new directive) https://github.com/spack/seps/blob/8dafadb4cae08275d168af964b3d168b4248977f/seps/sep-0002.md
    • (Notes on trying an approach based on a when class decorator) https://github.com/spack/seps/issues/4
  • Two approaches were covered: Greg thought there were issues with both; we will cover that next week.

• Discussion: Packages with multiple conflicting libraries - how to support them?

  • For now, any such package installed by Spack advertises just one from the set (this ensures that everything is consistent where needed)
  • https://github.com/spack/seps/pull/2
  • Brian: opencv will try to install its own openblas (which may conflict with what Spack chooses)
    • Mvapich2 installs its own hwloc
    • (Peter) I think this is a separate but still interesting problem.

• Discussion: long environment activations - are you having an issue with this?

  • Some large envs might have this problem, e.g.: https://github.com/spack/spack/issues/25555