constexpr int COLL_TAG_ALLTOALL = -1112;
constexpr int COLL_TAG_GATHERV = -2223;
constexpr int COLL_TAG_BCAST = -3334;
constexpr int COLL_TAG_ALLREDUCE = -4445;
constexpr int COLL_TAG_ALLTOALL = -1112;
constexpr int COLL_TAG_GATHERV = -2223;
constexpr int COLL_TAG_BCAST = -3334;
constexpr int COLL_TAG_ALLREDUCE = -4445;