diff --git a/opal/datatype/opal_datatype_get_count.c b/opal/datatype/opal_datatype_get_count.c
index ab2d69a8f3..ae085c4270 100644
--- a/opal/datatype/opal_datatype_get_count.c
+++ b/opal/datatype/opal_datatype_get_count.c
@@ -191,6 +191,9 @@ int opal_datatype_compute_ptypes( opal_datatype_t* datatype )
             datatype->ptypes[pElems[pos_desc].elem.common.type] += pElems[pos_desc].elem.count;
             nbElems += pElems[pos_desc].elem.count;
 
+            DUMP( "  compute_ptypes-add: type %d count %"PRIsize_t" (total type %"PRIsize_t" total %lld)\n",
+                  pElems[pos_desc].elem.common.type, datatype->ptypes[pElems[pos_desc].elem.common.type],
+                  pElems[pos_desc].elem.count, nbElems );
             pos_desc++;  /* advance to the next data */
         }
     }
diff --git a/opal/datatype/opal_datatype_internal.h b/opal/datatype/opal_datatype_internal.h
index 9ff3492149..bc3f8aa7ca 100644
--- a/opal/datatype/opal_datatype_internal.h
+++ b/opal/datatype/opal_datatype_internal.h
@@ -3,7 +3,7 @@
  * Copyright (c) 2004-2006 The Trustees of Indiana University and Indiana
  *                         University Research and Technology
  *                         Corporation.  All rights reserved.
- * Copyright (c) 2004-2017 The University of Tennessee and The University
+ * Copyright (c) 2004-2018 The University of Tennessee and The University
  *                         of Tennessee Research Foundation.  All rights
  *                         reserved.
  * Copyright (c) 2004-2006 High Performance Computing Center Stuttgart,
@@ -49,10 +49,9 @@ static inline void DUMP( char* fmt, ... )
    va_list list;
 
    va_start( list, fmt );
-   opal_output( opal_datatype_dfd, fmt, list );
+   opal_output_vverbose( 0, opal_datatype_dfd, fmt, list );
    va_end( list );
 }
-#      define DUMP                   printf
 #    endif  /* __GNUC__ && !__STDC__ */
 #  endif  /* ACCEPT_C99 */
 #else
@@ -329,8 +328,8 @@ struct opal_datatype_t;
         .ptypes = OPAL_DATATYPE_INIT_PTYPES_ARRAY_UNAVAILABLE                        \
     }
 
-#define OPAL_DATATYPE_INITIALIZER_LOOP(FLAGS)       OPAL_DATATYPE_INIT_BASIC_TYPE( OPAL_DATATYPE_LOOP, LOOP, FLAGS )
-#define OPAL_DATATYPE_INITIALIZER_END_LOOP(FLAGS)   OPAL_DATATYPE_INIT_BASIC_TYPE( OPAL_DATATYPE_END_LOOP, END_LOOP, FLAGS )
+#define OPAL_DATATYPE_INITIALIZER_LOOP(FLAGS)       OPAL_DATATYPE_INIT_BASIC_TYPE( OPAL_DATATYPE_LOOP, LOOP_S, FLAGS )
+#define OPAL_DATATYPE_INITIALIZER_END_LOOP(FLAGS)   OPAL_DATATYPE_INIT_BASIC_TYPE( OPAL_DATATYPE_END_LOOP, LOOP_E, FLAGS )
 #define OPAL_DATATYPE_INITIALIZER_LB(FLAGS)         OPAL_DATATYPE_INIT_BASIC_TYPE( OPAL_DATATYPE_LB, LB, FLAGS )
 #define OPAL_DATATYPE_INITIALIZER_UB(FLAGS)         OPAL_DATATYPE_INIT_BASIC_TYPE( OPAL_DATATYPE_UB, UB, FLAGS )
 #define OPAL_DATATYPE_INITIALIZER_INT1(FLAGS)       OPAL_DATATYPE_INIT_BASIC_DATATYPE( int8_t, OPAL_ALIGNMENT_INT8, INT1, FLAGS )
diff --git a/opal/datatype/opal_datatype_module.c b/opal/datatype/opal_datatype_module.c
index 7de8fae5b0..7b4f33e868 100644
--- a/opal/datatype/opal_datatype_module.c
+++ b/opal/datatype/opal_datatype_module.c
@@ -3,7 +3,7 @@
  * Copyright (c) 2004-2006 The Trustees of Indiana University and Indiana
  *                         University Research and Technology
  *                         Corporation.  All rights reserved.
- * Copyright (c) 2004-2013 The University of Tennessee and The University
+ * Copyright (c) 2004-2018 The University of Tennessee and The University
  *                         of Tennessee Research Foundation.  All rights
  *                         reserved.
  * Copyright (c) 2004-2006 High Performance Computing Center Stuttgart,
@@ -29,6 +29,7 @@
 #include <stddef.h>
 
 #include "opal/util/arch.h"
+#include "opal/util/output.h"
 #include "opal/datatype/opal_datatype_internal.h"
 #include "opal/datatype/opal_datatype.h"
 #include "opal/datatype/opal_convertor_internal.h"
@@ -40,6 +41,7 @@ bool opal_unpack_debug = false;
 bool opal_pack_debug = false;
 bool opal_position_debug = false;
 bool opal_copy_debug = false;
+int opal_ddt_verbose = -1;  /* Has the datatype verbose it's own output stream */
 
 extern int opal_cuda_verbose;
 
@@ -177,11 +179,19 @@ int opal_datatype_register_params(void)
 	return ret;
     }
 
+    ret = mca_base_var_register ("opal", "opal", NULL, "ddt_verbose",
+                                 "Set level of opal datatype verbosity",
+                                 MCA_BASE_VAR_TYPE_INT, NULL, 0, MCA_BASE_VAR_FLAG_SETTABLE,
+                                 OPAL_INFO_LVL_8, MCA_BASE_VAR_SCOPE_LOCAL,
+                                 &opal_ddt_verbose);
+    if (0 > ret) {
+        return ret;
+    }
 #if OPAL_CUDA_SUPPORT
     /* Set different levels of verbosity in the cuda related code. */
     ret = mca_base_var_register ("opal", "opal", NULL, "cuda_verbose",
                                  "Set level of opal cuda verbosity",
-                                 MCA_BASE_VAR_TYPE_INT, NULL, 0, MCA_BASE_VAR_FLAG_SETTABLE,
+                                 MCA_BASE_VAR_TYPE_INT, NULL, -1, MCA_BASE_VAR_FLAG_SETTABLE,
                                  OPAL_INFO_LVL_8, MCA_BASE_VAR_SCOPE_LOCAL,
                                  &opal_cuda_verbose);
     if (0 > ret) {
@@ -226,6 +236,12 @@ int32_t opal_datatype_init( void )
         datatype->desc.desc[1].end_loop.size            = datatype->size;
     }
 
+    /* Enable a private output stream for datatype */
+    if( opal_ddt_verbose > 0 ) {
+        opal_datatype_dfd = opal_output_open(NULL);
+        opal_output_set_verbosity(opal_datatype_dfd, opal_ddt_verbose);
+    }
+
     return OPAL_SUCCESS;
 }