--- /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"
+
+int bcast_arrival_pattern_aware_wait_segment_size_in_byte = 8192;
+
+#ifndef BCAST_ARRIVAL_PATTERN_AWARE_HEADER_SIZE
+#define BCAST_ARRIVAL_PATTERN_AWARE_HEADER_SIZE 1024
+#endif
+
+#ifndef BCAST_ARRIVAL_PATTERN_AWARE_MAX_NODE
+#define BCAST_ARRIVAL_PATTERN_AWARE_MAX_NODE 128
+#endif
+
+/* Non-topology-specific pipelined linear-bcast function */
+int smpi_coll_tuned_bcast_arrival_pattern_aware_wait(void *buf, int count,
+ MPI_Datatype datatype,
+ int root, MPI_Comm comm)
+{
+ 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;
+
+
+ MPI_Status temp_status_array[BCAST_ARRIVAL_PATTERN_AWARE_MAX_NODE];
+
+ int rank, size;
+ int i, j, k;
+ int tag = -COLL_TAG_BCAST;
+ int will_send[BCAST_ARRIVAL_PATTERN_AWARE_MAX_NODE];
+
+ int sent_count;
+ int header_index;
+ int flag_array[BCAST_ARRIVAL_PATTERN_AWARE_MAX_NODE];
+ int already_sent[BCAST_ARRIVAL_PATTERN_AWARE_MAX_NODE];
+
+ int header_buf[BCAST_ARRIVAL_PATTERN_AWARE_HEADER_SIZE];
+ char temp_buf[BCAST_ARRIVAL_PATTERN_AWARE_MAX_NODE];
+
+ int max_node = BCAST_ARRIVAL_PATTERN_AWARE_MAX_NODE;
+ int header_size = BCAST_ARRIVAL_PATTERN_AWARE_HEADER_SIZE;
+
+ MPI_Aint extent;
+ extent = smpi_datatype_get_extent(datatype);
+
+ /* source and destination */
+ int to, from;
+
+
+
+ rank = smpi_comm_rank(comm);
+ size = smpi_comm_size(comm);
+
+
+ /* segment is segment size in number of elements (not bytes) */
+ int segment = bcast_arrival_pattern_aware_wait_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);
+ }
+ }
+
+
+ /* value == 0 means root has not send data (or header) to the node yet */
+ for (i = 0; i < max_node; i++) {
+ already_sent[i] = 0;
+ }
+
+ /* when a message is smaller than a block size => no pipeline */
+ if (count <= segment) {
+ segment = count;
+ pipe_length = 1;
+ }
+
+ /* start pipeline bcast */
+
+ 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 */
+ if (rank == 0) {
+ sent_count = 0;
+ int iteration = 0;
+
+ for (i = 0; i < BCAST_ARRIVAL_PATTERN_AWARE_MAX_NODE; i++)
+ will_send[i] = 0;
+ while (sent_count < (size - 1)) {
+ iteration++;
+
+ /* loop k times to let more processes arrive before start sending data */
+ for (k = 0; k < 3; k++) {
+ for (i = 1; i < size; i++) {
+ if ((already_sent[i] == 0) && (will_send[i] == 0)) {
+ smpi_mpi_iprobe(i, MPI_ANY_TAG, comm, &flag_array[i],
+ &temp_status_array[i]);
+ if (flag_array[i] == 1) {
+ will_send[i] = 1;
+ smpi_mpi_recv(&temp_buf[i], 1, MPI_CHAR, i, tag, comm,
+ &status);
+ i = 0;
+ }
+ }
+ }
+ }
+
+ header_index = 0;
+
+ /* recv 1-byte message */
+ for (i = 1; i < size; i++) {
+ /* message arrive */
+ if ((will_send[i] == 1) && (already_sent[i] == 0)) {
+ header_buf[header_index] = i;
+ header_index++;
+ sent_count++;
+
+ /* will send in the next step */
+ already_sent[i] = 1;
+ }
+ }
+
+ /* send header followed by data */
+ if (header_index != 0) {
+ header_buf[header_index] = -1;
+ to = header_buf[0];
+
+ /* send header */
+ smpi_mpi_send(header_buf, header_size, MPI_INT, to, tag, comm);
+
+ /* send data - pipeline */
+ for (i = 0; i < pipe_length; i++) {
+ send_request_array[i] = smpi_mpi_isend((char *)buf + (i * increment), segment, datatype, to, tag, comm);
+ }
+ smpi_mpi_waitall((pipe_length), send_request_array, send_status_array);
+ }
+
+
+ /* end - send header followed by data */
+ /* randomly MPI_Send to one node */
+ /* this part has been commented out - performance-wise */
+ else if (2 == 3) {
+ /* search for the first node that never received data before */
+ for (i = 0; i < size; i++) {
+ if (i == root)
+ continue;
+ if (already_sent[i] == 0) {
+ header_buf[0] = i;
+ header_buf[1] = -1;
+ to = i;
+
+ smpi_mpi_send(header_buf, header_size, MPI_INT, to, tag, comm);
+
+ /* still need to chop data so that we can use the same non-root code */
+ for (j = 0; j < pipe_length; j++) {
+ smpi_mpi_send((char *)buf + (j * increment), segment, datatype, to, tag, comm);
+ }
+ }
+ }
+ }
+ } /* end - while (send_count < size-1) loop */
+ }
+
+ /* end - root */
+ /* none root */
+ else {
+
+ /* send 1-byte message to root */
+ smpi_mpi_send(temp_buf, 1, MPI_CHAR, 0, tag, comm);
+
+ /* wait for header forward when required */
+ request = smpi_mpi_irecv(header_buf, header_size, MPI_INT, MPI_ANY_SOURCE, tag, comm);
+ smpi_mpi_wait(&request, MPI_STATUS_IGNORE);
+
+ /* search for where it is */
+ int myordering = 0;
+ while (rank != header_buf[myordering]) {
+ myordering++;
+ }
+
+ to = header_buf[myordering + 1];
+ if (myordering == 0) {
+ from = 0;
+ } else {
+ from = header_buf[myordering - 1];
+ }
+
+ /* send header when required */
+ if (to != -1) {
+ smpi_mpi_send(header_buf, header_size, MPI_INT, to, tag, comm);
+ }
+
+ /* receive data */
+
+ for (i = 0; i < pipe_length; i++) {
+ recv_request_array[i] = smpi_mpi_irecv((char *)buf + (i * increment), segment, datatype, from, tag, comm);
+ }
+
+ /* forward data */
+ if (to != -1) {
+ for (i = 0; i < pipe_length; i++) {
+ smpi_mpi_wait(&recv_request_array[i], MPI_STATUS_IGNORE);
+ send_request_array[i] = smpi_mpi_isend((char *)buf + (i * increment), segment, datatype, to, tag, comm);
+ }
+ smpi_mpi_waitall((pipe_length), send_request_array, send_status_array);
+ }
+
+ /* recv only */
+ else {
+ smpi_mpi_waitall((pipe_length), recv_request_array, recv_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_arrival_pattern_aware_wait use default MPI_bcast.");
+ smpi_mpi_bcast((char *)buf + (pipe_length * increment), remainder, datatype, root, comm);
+ }
+
+ return MPI_SUCCESS;
+}
