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Teams subcommittee and collectives

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Nick Park edited this page Jan 29, 2019 · 17 revisions

Topic Areas

OpenSHMEM teams (a.k.a. communicator) and collective operations
Subcommittee chair: Pavel Shamis, Gorentla Venkata, Manjunath

Meeting Information

Bi-Weekly on Thursdays, 11-12AM CST starting on March. 22, 2018.

Join online meeting: https://meet.lync.com/armh/pavel.shamis/0QV03A21
Join by Phone: +1 (213) 336-0288,, 95616526# .
Find a local number: https://dialin.lync.com/7bdb65cd-97d0-44fe-bc03-bf8072eadc33
Conference ID: 95616526

Active Topics

The following topics are under active discussion for the next version of the OpenSHMEM specification:

  • Teams proposal
  • Teams integration with context
  • Teams integration with collective API

Meeting Minutes

Up-to-date Teams WG meeting notes are kept here.

June-14-2018

Anshuman's meeting minutes google doc Arm notes:

  • 3d_split - define the behaviour for the case when we have more or less PE's per dimension.
  • shmem_team_transalte should return -1 if the PE not in the destination and/or source team
  • It seems like combination of context and teams it the best path forward
  • Remove undefined behavior
  • only PE that are in the team will be participating in team creation call (asked in context of father/child team)
  • Father team can be destroyed while child team may continue to exists
  • Question about implementation - Cray has an implementation which is very similar to the current team definition
  • ORNL - will discuss the direction towards consolidation

ARs:

  • Naveen and Nick volunteer to help with transition to git/latex
  • Megan and Anshuman will kick off on the write up based on Cray's manual pages.
  • Pasha: setup new conf call. For whatever reason bluejeans does not work anymore.

Mar-01-2018

On going debate - do we want to maintain shmem_team_t as a standalone object that is passed as a separate argument to all p2p and collective operations or it should be a part of context.

1. shmem_team_t as a stand alone argument:

Pros

  • shmem_team_t and context a conceptually two different concept and object. The team represent collection of resources where context represents isolated communication conduit (typically allocated per-thread)
  • Allows any mix-and-match combinations of teams and context

Cons

  • Adds extra argument to all p2p operations

2. shmem_team_t as an object attached to context:

Pros

  • We can leverage existing context argument for passing team to p2p.

Cons

  • The notion and concept of context becomes rather very confusing. It is not cleat what it actually represents.
  • Will require additional team-to-context attach/detach routines. This routines will have the overhead of "quiet" on the context before we actually can change the team.

Teams API draft

Draft Here

Teams, Contexts, and Symmetric Heaps

WIP: API and examples sketch considering teams, contexts, and team-based symmetric heaps

Clone this wiki locally