08 19 2020

Participants

• Manjunath Gorentla Venkata
• Sergey Lebedev
• Valentine Petrov
• Alex Margolin
• Geoffroy Valle
• Lior

Discussion on the API PR

• https://github.com/openucx/ucc/pull/1#discussion_r465931967

  • No changes. The ucc_aint_t and ucc_count to stay, so both MPI 3 and MPI 4 requirements can be supported.

• https://github.com/openucx/ucc/pull/1#discussion_r465933922

  • Merge the reduction_info, op_args, and ext_op_args structures. Remove mask from the buffer info.
  • Introduce buffer info structure to reflect the requirements for collectives that have single count buffers.

• https://github.com/openucx/ucc/pull/1#discussion_r469280817

  • Will add a reduction wrapper/callback to address the needs of user-defined reductions and user-defined datatypes
  • We can add more library tailoring operations as needed.

• https://github.com/openucx/ucc/pull/1#discussion_r469281871

  • A separate field for “user-defined” reductions will be added.
  • User need to pass UCC_OP_USERDEFINED option and reduction function to UCC

• https://github.com/openucx/ucc/pull/1#discussion_r469288225

  • Briefly discussed this and will continue the discussion in the next meeting.

• https://github.com/openucx/ucc/pull/1#discussion_r469303879

  • Will not support implicit creation and destruction of the request object.
  • Discuss with MPICH team, if they need request object to be created by the MPICH rather than UCC

• https://github.com/openucx/ucc/pull/1#discussion_r469284303

  • Given that the structure can be expanded (mask), we can add additional filters as we find compelling use cases.

• https://github.com/openucx/ucc/pull/1#discussion_r469285526

  • Instead of enum+pointer, we will have a “user-defined” reduction filed to coll_op_args.

CI Update from Val/Sergey

• For now, use GitHub actions and eventually use the infrastructure used by the UCX project.
  • UCX is moving to a new infrastructure.
• Discussion with NVIDIA/Mellanox's DevOps going on.

Next meeting

Sep 2, 2020