Move collective algorithms to separate folders

[simgrid.git] / src / smpi / colls / alltoall / alltoall-ring-light-barrier.cpp

diff --git a/src/smpi/colls/alltoall/alltoall-ring-light-barrier.cpp b/src/smpi/colls/alltoall/alltoall-ring-light-barrier.cpp
new file mode 100644 (file)
index 0000000..f670da3
--- /dev/null
+++ b/src/smpi/colls/alltoall/alltoall-ring-light-barrier.cpp
@@ -0,0 +1,76 @@
+/* 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"
+/*****************************************************************************
+
+ * Function: alltoall_ring_light_barrier
+
+ * Return: int
+
+ * Inputs:
+    send_buff: send input buffer
+    send_count: number of elements to send
+    send_type: data type of elements being sent
+    recv_buff: receive output buffer
+    recv_count: number of elements to received
+    recv_type: data type of elements being received
+    comm: communicator
+
+ * Descrp: Function works in P - 1 steps. In step i, node j - i -> j -> j + i.
+           Light barriers are inserted between communications in different
+           phases.
+
+ * Auther: Ahmad Faraj
+
+ ****************************************************************************/
+int
+smpi_coll_tuned_alltoall_ring_light_barrier(void *send_buff, int send_count,
+                                            MPI_Datatype send_type,
+                                            void *recv_buff, int recv_count,
+                                            MPI_Datatype recv_type,
+                                            MPI_Comm comm)
+{
+  MPI_Aint send_chunk, recv_chunk;
+  MPI_Status s;
+  int i, src, dst, rank, num_procs, next_dst, next_src;
+  int tag = COLL_TAG_ALLTOALL;
+
+  char send_sync = 'a', recv_sync = 'b';
+  char *send_ptr = (char *) send_buff;
+  char *recv_ptr = (char *) recv_buff;
+
+  rank = comm->rank();
+  num_procs = comm->size();
+  send_chunk = send_type->get_extent();
+  recv_chunk = recv_type->get_extent();
+
+  send_chunk *= send_count;
+  recv_chunk *= recv_count;
+
+  Request::sendrecv(send_ptr + rank * send_chunk, send_count, send_type, rank, tag,
+               recv_ptr + rank * recv_chunk, recv_count, recv_type, rank, tag,
+               comm, &s);
+
+  for (i = 1; i < num_procs; i++) {
+    src = (rank - i + num_procs) % num_procs;
+    dst = (rank + i) % num_procs;
+
+    Request::sendrecv(send_ptr + dst * send_chunk, send_count, send_type,
+                 dst, tag, recv_ptr + src * recv_chunk, recv_count,
+                 recv_type, src, tag, comm, &s);
+
+    if ((i + 1) < num_procs) {
+      next_src = (rank - (i + 1) + num_procs) % num_procs;
+      next_dst = (rank + (i + 1) + num_procs) % num_procs;
+      Request::sendrecv(&send_sync, 1, MPI_CHAR, next_src, tag,
+                   &recv_sync, 1, MPI_CHAR, next_dst, tag, comm, &s);
+
+    }
+  }
+
+  return MPI_SUCCESS;
+}