bcast on one process is a no-op

[simgrid.git] / src / smpi / smpi_pmpi.cpp

diff --git a/src/smpi/smpi_pmpi.cpp b/src/smpi/smpi_pmpi.cpp
index 5a3cd2a..707e29f 100644 (file)
--- a/src/smpi/smpi_pmpi.cpp
+++ b/src/smpi/smpi_pmpi.cpp
@@ -1494,11 +1494,14 @@ int PMPI_Waitany(int count, MPI_Request requests[], int *index, MPI_Status * sta
   smpi_bench_end();
   //save requests information for tracing
   int i;
-  int *srcs = xbt_new0(int, count);
-  int *dsts = xbt_new0(int, count);
-  int *recvs = xbt_new0(int, count);
-  MPI_Comm *comms = xbt_new0(MPI_Comm, count);
-
+  int *srcs = NULL, *dsts = NULL, *recvs = NULL;
+  MPI_Comm* comms = NULL;
+  if(count>0){
+    srcs = xbt_new0(int, count);
+    dsts = xbt_new0(int, count);
+    recvs = xbt_new0(int, count);
+    comms = xbt_new0(MPI_Comm, count);
+  }
   for (i = 0; i < count; i++) {
     MPI_Request req = requests[i];      //already received requests are no longer valid
     if (req) {
@@ -1651,11 +1654,11 @@ int PMPI_Bcast(void *buf, int count, MPI_Datatype datatype, int root, MPI_Comm c
     dt_size_send = smpi_datatype_size(datatype);
   extra->send_size = count*dt_size_send;
   TRACE_smpi_collective_in(rank, root_traced, __FUNCTION__, extra);
-
+  if(smpi_comm_size(comm)>1)
     mpi_coll_bcast_fun(buf, count, datatype, root, comm);
-    retval = MPI_SUCCESS;
+  retval = MPI_SUCCESS;
 
-    TRACE_smpi_collective_out(rank, root_traced, __FUNCTION__);
+  TRACE_smpi_collective_out(rank, root_traced, __FUNCTION__);
   }
 
   smpi_bench_begin();