--- /dev/null
+/* Copyright (c) 2013-2014. The SimGrid Team.
+ * All rights reserved. */
+
+/* This program is free software; you can redistribute it and/or modify it
+ * under the terms of the license (GNU LGPL) which comes with this package. */
+
+#include "colls_private.h"
+
+static int bcast_NTSL_segment_size_in_byte = 8192;
+
+/* Non-topology-specific pipelined linear-bcast function
+ 0->1, 1->2 ,2->3, ....., ->last node : in a pipeline fashion
+*/
+int smpi_coll_tuned_bcast_NTSL_Isend(void *buf, int count, MPI_Datatype datatype,
+ int root, MPI_Comm comm)
+{
+ int tag = COLL_TAG_BCAST;
+ MPI_Status status;
+ MPI_Request request;
+ MPI_Request *send_request_array;
+ MPI_Request *recv_request_array;
+ MPI_Status *send_status_array;
+ MPI_Status *recv_status_array;
+ int rank, size;
+ int i;
+ MPI_Aint extent;
+ extent = smpi_datatype_get_extent(datatype);
+
+ rank = smpi_comm_rank(comm);
+ size = smpi_comm_size(comm);
+
+ /* source node and destination nodes (same through out the functions) */
+ int to = (rank + 1) % size;
+ int from = (rank + size - 1) % size;
+
+ /* segment is segment size in number of elements (not bytes) */
+ int segment = bcast_NTSL_segment_size_in_byte / extent;
+ segment = segment == 0 ? 1 :segment;
+ /* pipeline length */
+ int pipe_length = count / segment;
+
+ /* use for buffer offset for sending and receiving data = segment size in byte */
+ int increment = segment * extent;
+
+ /* if the input size is not divisible by segment size =>
+ the small remainder will be done with native implementation */
+ int remainder = count % segment;
+
+ /* if root is not zero send to rank zero first
+ this can be modified to make it faster by using logical src, dst.
+ */
+ if (root != 0) {
+ if (rank == root) {
+ smpi_mpi_send(buf, count, datatype, 0, tag, comm);
+ } else if (rank == 0) {
+ smpi_mpi_recv(buf, count, datatype, root, tag, comm, &status);
+ }
+ }
+
+ /* when a message is smaller than a block size => no pipeline */
+ if (count <= segment) {
+ if (rank == 0) {
+ smpi_mpi_send(buf, count, datatype, to, tag, comm);
+ } else if (rank == (size - 1)) {
+ request = smpi_mpi_irecv(buf, count, datatype, from, tag, comm);
+ smpi_mpi_wait(&request, &status);
+ } else {
+ request = smpi_mpi_irecv(buf, count, datatype, from, tag, comm);
+ smpi_mpi_wait(&request, &status);
+ smpi_mpi_send(buf, count, datatype, to, tag, comm);
+ }
+ return MPI_SUCCESS;
+ }
+
+ /* pipeline bcast */
+ else {
+ send_request_array =
+ (MPI_Request *) xbt_malloc((size + pipe_length) * sizeof(MPI_Request));
+ recv_request_array =
+ (MPI_Request *) xbt_malloc((size + pipe_length) * sizeof(MPI_Request));
+ send_status_array =
+ (MPI_Status *) xbt_malloc((size + pipe_length) * sizeof(MPI_Status));
+ recv_status_array =
+ (MPI_Status *) xbt_malloc((size + pipe_length) * sizeof(MPI_Status));
+
+ /* root send data */
+ if (rank == 0) {
+ for (i = 0; i < pipe_length; i++) {
+ send_request_array[i] = smpi_mpi_isend((char *) buf + (i * increment), segment, datatype, to,
+ (tag + i), comm);
+ }
+ smpi_mpi_waitall((pipe_length), send_request_array, send_status_array);
+ }
+
+ /* last node only receive data */
+ else if (rank == (size - 1)) {
+ for (i = 0; i < pipe_length; i++) {
+ recv_request_array[i] = smpi_mpi_irecv((char *) buf + (i * increment), segment, datatype, from,
+ (tag + i), comm);
+ }
+ smpi_mpi_waitall((pipe_length), recv_request_array, recv_status_array);
+ }
+
+ /* intermediate nodes relay (receive, then send) data */
+ else {
+ for (i = 0; i < pipe_length; i++) {
+ recv_request_array[i] = smpi_mpi_irecv((char *) buf + (i * increment), segment, datatype, from,
+ (tag + i), comm);
+ }
+ for (i = 0; i < pipe_length; i++) {
+ smpi_mpi_wait(&recv_request_array[i], &status);
+ send_request_array[i] = smpi_mpi_isend((char *) buf + (i * increment), segment, datatype, to,
+ (tag + i), comm);
+ }
+ smpi_mpi_waitall((pipe_length), send_request_array, send_status_array);
+ }
+
+ free(send_request_array);
+ free(recv_request_array);
+ free(send_status_array);
+ free(recv_status_array);
+ } /* end pipeline */
+
+ /* when count is not divisible by block size, use default BCAST for the remainder */
+ if ((remainder != 0) && (count > segment)) {
+ XBT_WARN("MPI_bcast_NTSL_Isend_nb use default MPI_bcast.");
+ smpi_mpi_bcast((char *) buf + (pipe_length * increment), remainder, datatype,
+ root, comm);
+ }
+
+ return MPI_SUCCESS;
+}
