smpi_mpi_sendrecv((char *) rbuff + send_idx * extent, send_cnt, dtype, dst,
tag, tmp_buf, recv_cnt, dtype, dst, tag, comm, &status);
smpi_mpi_sendrecv((char *) rbuff + send_idx * extent, send_cnt, dtype, dst,
tag, tmp_buf, recv_cnt, dtype, dst, tag, comm, &status);