06 10 2020 - openucx/ucx GitHub Wiki

Participants

• Manjunath Gorentla Venkata
• Sergey Lebedev
• Valentin Petrov
• Alex Margolin
• Gil Bloch
• Pavel Shamis
• Naveen Ravi

Discussion on the UCC interface details

https://github.com/manjugv/ucc_wg_public/blob/master/docs/UCC_V1.0_API_Draft_gorentla.pdf

###Specific topics discussed

• UCC thread model discussion
  • Should UCC support all four models - SINGLE, MULTIPLE, SERIALIZED, FUNNELED
  • Inclination towards supporting SINGLE, SERIALIZED, and MULTIPLE
• BFloat16 vs FP16 datatype for reduction ?
  • What should UCC support ? BFloat16 or FP16 or both?
  • Need more input
• Support for MPI_Comm_split with colors or the current UCC interface [2]
  • Research the current literature and state of art
• When does buffer ownership transfer from user to library ?
  • Two models (1) Transfer after ucc_collective_init() (2) Transfer after ucc_collective_finalized()
  • Model 1 : Supports persistent collectives
  • Model 2 : Supports RDMA based implementation
• Signature for OOB collective team creation

typedef struct ucc_team_oob_coll_t {
  int             (*allgather)(void *src_buf, void *recv_buf, size_t size,
                        void *allgather_info,  void **request);
  ucc_status_t    (*req_test)(void *request);
  ucc_status_t    (*req_free)(void *request);
  uint32_t 	  participants;
  void            *coll_info;
} ucc_team_oob_coll_t

Next Meeting

• June 17th, 2020