Add Reduce SMP collective from MVAPICH2

[simgrid.git] / src / smpi / colls / reduce-scatter-gather.c

diff --git a/src/smpi/colls/reduce-scatter-gather.c b/src/smpi/colls/reduce-scatter-gather.c
index 2c61d48..30d5e6e 100644 (file)
--- a/src/smpi/colls/reduce-scatter-gather.c
+++ b/src/smpi/colls/reduce-scatter-gather.c
@@ -1,3 +1,9 @@
+/* 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"
 
 /*
@@ -15,7 +21,7 @@ int smpi_coll_tuned_reduce_scatter_gather(void *sendbuf, void *recvbuf,
   int recv_idx, last_idx = 0, newdst;
   int dst, send_cnt, recv_cnt, newroot, newdst_tree_root;
   int newroot_tree_root, new_count;
-  int tag = 4321;
+  int tag = COLL_TAG_REDUCE;
   void *send_ptr, *recv_ptr, *tmp_buf;
 
   cnts = NULL;
@@ -27,9 +33,15 @@ int smpi_coll_tuned_reduce_scatter_gather(void *sendbuf, void *recvbuf,
     return 0;
   rank = smpi_comm_rank(comm);
   comm_size = smpi_comm_size(comm);
+  
 
-  extent = smpi_datatype_get_extent(datatype);
 
+  extent = smpi_datatype_get_extent(datatype);
+  /* If I'm not the root, then my recvbuf may not be valid, therefore
+  I have to allocate a temporary one */
+  if (rank != root && !recvbuf) {
+    recvbuf = (void *)xbt_malloc(count * extent);
+  }
   /* find nearest power-of-two less than or equal to comm_size */
   pof2 = 1;
   while (pof2 <= comm_size)
@@ -216,7 +228,7 @@ int smpi_coll_tuned_reduce_scatter_gather(void *sendbuf, void *recvbuf,
   }
 
 
-  else if (count >= comm_size) {
+  else /* (count >= comm_size) */ {
     tmp_buf = (void *) xbt_malloc(count * extent);
 
     //if ((rank != root))
@@ -387,6 +399,8 @@ int smpi_coll_tuned_reduce_scatter_gather(void *sendbuf, void *recvbuf,
       }
     }
   }
+  if (tmp_buf)
+    free(tmp_buf);
   if (cnts)
     free(cnts);
   if (disps)