int dst_tree_root, rank_tree_root, last_recv_count = 0, num_procs_completed;
int offset, tmp_mask;
int tag = COLL_TAG_ALLGATHER;
int dst_tree_root, rank_tree_root, last_recv_count = 0, num_procs_completed;
int offset, tmp_mask;
int tag = COLL_TAG_ALLGATHER;