message: add MPI_Barrier;useful for large meshes
diff: @@ -5142,6 +5142,7 @@ void ParMesh::PrintAsSerial(std::ostream &os) const
  {
  serialmesh.Printer(os);
  }
  + MPI_Barrier(MyComm);
  }
  Mesh ParMesh::GetSerialMesh(int save_rank) const
  @@ -5453,6 +5454,7 @@ Mesh ParMesh::GetSerialMesh(int save_rank) const
  }
  }
  + MPI_Barrier(MyComm);
  return serialmesh;
  }
  