Notes 2020 04 30

Meeting 2020-04-30

Participants

• Marc-Andre Hermanns
• Michael Knobloch
• Bengisu Elis
• Bharath Ramesh
• Joachim Protze
• John DelSignore
• Kathryn Mohror
• Martin Schulz

Topics

Handle Introspection

• How to implement the prototype

  • PMPI-based implementation favored
    • Direct integration into one of the MPI implementations may be too daring without direct involvement of one of the core developers

• This is a third party interface

  • Similar to OMPD
    • Focussing on opaque handles
  • First get a debugging handle for an MPI handle
    • Use debugging handle further on
  • Bootstrapping problem also applies here
  • OMPD was partly inspired by handle introspection/MQD
    • Leverage common characterisitcs
  • Potentially develop a first party interface from this

• Wiki vs. Issue vs. Google Doc?

  • Brainstorm/Sketch via Google Docs Presentation (that can easily be used to present at a meeting)
  • Work on a specific issue once concepts are clear and we work on the text

• Proposal has to core topics

  • Bootstrap

    • Getting Debugger & Library in touch
    • Initializing the library
      • ompd_initialize & ompd_process_initialize
      • Would this be different for MPI? Would this work for MPI?
        • Each process might have a different DLL
          • On each node each process will likely use the same MPI library
          • Interface still supports the case where it would be different
    • Providing the callbacks
    • List of shared-library names
      • Variable (argv-style vector) ompd_dll_locations
      • Rules in the standard
      • OMPD Env-Var informs runtime about presence of debugger

  • Library

    • Interaction with debugger

• Use Cases

  • Debug inconsistent states of handles