Add collectives for allgather, allreduce, bcast and reduce

[simgrid.git] / src / smpi / colls / allreduce-rab1.c

diff --git a/src/smpi/colls/allreduce-rab1.c b/src/smpi/colls/allreduce-rab1.c
new file mode 100644 (file)
index 0000000..0dc64c1
--- /dev/null
+++ b/src/smpi/colls/allreduce-rab1.c
@@ -0,0 +1,101 @@
+#include "colls.h"
+//#include <star-reduction.c>
+
+// NP pow of 2 for now
+int smpi_coll_tuned_allreduce_rab1(void *sbuff, void *rbuff,
+                                   int count, MPI_Datatype dtype,
+                                   MPI_Op op, MPI_Comm comm)
+{
+  MPI_Status status;
+  MPI_Aint extent;
+  int tag = 4321, rank, nprocs, send_size, newcnt, share;
+  int pof2 = 1, mask, send_idx, recv_idx, dst, send_cnt, recv_cnt;
+
+  void *recv, *tmp_buf;
+
+  MPI_Comm_rank(comm, &rank);
+  MPI_Comm_size(comm, &nprocs);
+
+  MPI_Type_extent(dtype, &extent);
+
+  pof2 = 1;
+  while (pof2 <= nprocs)
+    pof2 <<= 1;
+  pof2 >>= 1;
+
+  mask = 1;
+  send_idx = recv_idx = 0;
+
+  // uneven count
+  if ((count % nprocs)) {
+    send_size = (count + nprocs) / nprocs;
+    newcnt = send_size * nprocs;
+
+    recv = (void *) malloc(extent * newcnt);
+    tmp_buf = (void *) malloc(extent * newcnt);
+    memcpy(recv, sbuff, extent * count);
+
+
+    mask = pof2 / 2;
+    share = newcnt / pof2;
+    while (mask > 0) {
+      dst = rank ^ mask;
+      send_cnt = recv_cnt = newcnt / (pof2 / mask);
+
+      if (rank < dst)
+        send_idx = recv_idx + (mask * share);
+      else
+        recv_idx = send_idx + (mask * share);
+
+      MPI_Sendrecv((char *) recv + send_idx * extent, send_cnt, dtype, dst, tag,
+                   tmp_buf, recv_cnt, dtype, dst, tag, comm, &status);
+
+      star_reduction(op, tmp_buf, (char *) recv + recv_idx * extent, &recv_cnt,
+                     &dtype);
+
+      // update send_idx for next iteration 
+      send_idx = recv_idx;
+      mask >>= 1;
+    }
+
+    memcpy(tmp_buf, (char *) recv + recv_idx * extent, recv_cnt * extent);
+    MPI_Allgather(tmp_buf, recv_cnt, dtype, recv, recv_cnt, dtype, comm);
+
+    memcpy(rbuff, recv, count * extent);
+    free(recv);
+    free(tmp_buf);
+
+  }
+
+  else {
+    tmp_buf = (void *) malloc(extent * count);
+    memcpy(rbuff, sbuff, count * extent);
+    mask = pof2 / 2;
+    share = count / pof2;
+    while (mask > 0) {
+      dst = rank ^ mask;
+      send_cnt = recv_cnt = count / (pof2 / mask);
+
+      if (rank < dst)
+        send_idx = recv_idx + (mask * share);
+      else
+        recv_idx = send_idx + (mask * share);
+
+      MPI_Sendrecv((char *) rbuff + send_idx * extent, send_cnt, dtype, dst,
+                   tag, tmp_buf, recv_cnt, dtype, dst, tag, comm, &status);
+
+      star_reduction(op, tmp_buf, (char *) rbuff + recv_idx * extent, &recv_cnt,
+                     &dtype);
+
+      // update send_idx for next iteration 
+      send_idx = recv_idx;
+      mask >>= 1;
+    }
+
+    memcpy(tmp_buf, (char *) rbuff + recv_idx * extent, recv_cnt * extent);
+    MPI_Allgather(tmp_buf, recv_cnt, dtype, rbuff, recv_cnt, dtype, comm);
+    free(tmp_buf);
+  }
+
+  return 0;
+}