Notes 2016 03 24

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Marc-Andre Hermanns edited this page Apr 14, 2016 · 3 revisions

Participants

Jean-Baptiste Besnard
James Custer
Marc-Andre Hermanns
Kathryn Mohror
Soren Rassmussen
Jeff Squyres

Topics

Forum #6: MPIR line numbers
- Tools group agrees that document can get scheduled for a reading
- Marc-Andre to create appropriate pull request.
Tools #7: fix whitespace in sources
- Marc-Andre to create appropriate pull request.
Tools #9: high resolution timer
- Should this timer be different from MPI_Wtime()?
- Forum will likely declare this a quality-of-implementation issue
- Maybe advice to implementors?
MPI_T Events
- We need a flexible interface
  - Different sources for events
  - Different types of events
  - Different times at which events could be gathered
- Some events need internal queues, because they occur in situations where a callback cannot be triggered
  - Network hardware starting or ending a transfer
  - Events would need a timestamp
    - Which clock source would the generator use?
    - Can we use MPI_Wtime? Is double return value a problem for accuracy?
- Where will the callback be triggered.
  - Tools would prefer the entity/thread where it was registered
  - This might be difficult in some situations
  - How to incorporate events into thread-local event stream?
    - separate streams for these callbacks.
    - Tool may provide a link to thread-local storage with "state" pointer to callback