score: Optimize scheduler priority updates

Thread priority changes may append or prepend the thread to its priority
group on the scheduler ready queue.  Previously, a separate priority
value and a prepend-it flag in the scheduler node were used to propagate
a priority change to the scheduler.

Now, use an append-it bit in the priority control and reduce the plain
priority value to 63 bits.

This change leads to a significant code size reduction (about 25%) of
the SMP schedulers.  The negligible increase of the standard priority
scheduler is due to some additional shift operations
(SCHEDULER_PRIORITY_MAP() and SCHEDULER_PRIORITY_UNMAP()).

Before:

   text filename
    136 sparc-rtems5/c/erc32/cpukit/score/src/libscore_a-schedulersimpleblock.o
    464 sparc-rtems5/c/erc32/cpukit/score/src/libscore_a-schedulersimplechangepriority.o
     24 sparc-rtems5/c/erc32/cpukit/score/src/libscore_a-schedulersimple.o
    108 sparc-rtems5/c/erc32/cpukit/score/src/libscore_a-schedulersimpleschedule.o
    292 sparc-rtems5/c/erc32/cpukit/score/src/libscore_a-schedulersimpleunblock.o
    264 sparc-rtems5/c/erc32/cpukit/score/src/libscore_a-schedulersimpleyield.o

   text filename
    280 sparc-rtems5/c/erc32/cpukit/score/src/libscore_a-schedulerpriorityblock.o
    488 sparc-rtems5/c/erc32/cpukit/score/src/libscore_a-schedulerprioritychangepriority.o
    200 sparc-rtems5/c/erc32/cpukit/score/src/libscore_a-schedulerpriority.o
    164 sparc-rtems5/c/erc32/cpukit/score/src/libscore_a-schedulerpriorityschedule.o
    328 sparc-rtems5/c/erc32/cpukit/score/src/libscore_a-schedulerpriorityunblock.o
    200 sparc-rtems5/c/erc32/cpukit/score/src/libscore_a-schedulerpriorityyield.o

   text filename
  24112 arm-rtems5/c/imx7/cpukit/score/src/libscore_a-scheduleredfsmp.o

   text filename
  37204 sparc-rtems5/c/gr740/cpukit/score/src/libscore_a-scheduleredfsmp.o

   text filename
  42236 powerpc-rtems5/c/qoriq_e6500_32/cpukit/score/src/libscore_a-scheduleredfsmp.o

After:

   text filename
    136 sparc-rtems5/c/erc32/cpukit/score/src/libscore_a-schedulersimpleblock.o
    272 sparc-rtems5/c/erc32/cpukit/score/src/libscore_a-schedulersimplechangepriority.o
     24 sparc-rtems5/c/erc32/cpukit/score/src/libscore_a-schedulersimple.o
    108 sparc-rtems5/c/erc32/cpukit/score/src/libscore_a-schedulersimpleschedule.o
    292 sparc-rtems5/c/erc32/cpukit/score/src/libscore_a-schedulersimpleunblock.o
    264 sparc-rtems5/c/erc32/cpukit/score/src/libscore_a-schedulersimpleyield.o

   text filename
    280 sparc-rtems5/c/erc32/cpukit/score/src/libscore_a-schedulerpriorityblock.o
    488 sparc-rtems5/c/erc32/cpukit/score/src/libscore_a-schedulerprioritychangepriority.o
    208 sparc-rtems5/c/erc32/cpukit/score/src/libscore_a-schedulerpriority.o
    164 sparc-rtems5/c/erc32/cpukit/score/src/libscore_a-schedulerpriorityschedule.o
    332 sparc-rtems5/c/erc32/cpukit/score/src/libscore_a-schedulerpriorityunblock.o
    200 sparc-rtems5/c/erc32/cpukit/score/src/libscore_a-schedulerpriorityyield.o

   text filename
  18860 arm-rtems5/c/imx7/cpukit/score/src/libscore_a-scheduleredfsmp.o

   text filename
  28520 sparc-rtems5/c/gr740/cpukit/score/src/libscore_a-scheduleredfsmp.o

   text filename
  32664 powerpc-rtems5/c/qoriq_e6500_32/cpukit/score/src/libscore_a-scheduleredfsmp.o

28 files changed, 495 insertions, 870 deletions

diff --git a/cpukit/score/include/rtems/score/priority.h b/cpukit/score/include/rtems/score/priority.h
index 9cc6338288..7a8ddba763 100644
--- a/cpukit/score/include/rtems/score/priority.h
+++ b/cpukit/score/include/rtems/score/priority.h
@@ -8,7 +8,7 @@
  *  COPYRIGHT (c) 1989-2011.
  *  On-Line Applications Research Corporation (OAR).
  *
- *  Copyright (c) 2016 embedded brains GmbH.
+ *  Copyright (c) 2016, 2017 embedded brains GmbH.
  *
  *  The license and distribution terms for this file may be
  *  found in the file LICENSE in this distribution or at
@@ -45,11 +45,23 @@ extern "C" {
  */
 
 /**
- * @brief A plain thread priority value.
+ * @brief The thread priority control.
  *
  * Lower values represent higher priorities.  So, a priority value of zero
  * represents the highest priority thread.  This value is reserved for internal
  * threads and the priority ceiling protocol.
+ *
+ * The format of the thread priority control depends on the context.  A thread
+ * priority control may contain a user visible priority for API import/export.
+ * It may also contain a scheduler internal priority value.  Values are
+ * translated via the scheduler map/unmap priority operations.  The format of
+ * scheduler interal values depend on the particular scheduler implementation.
+ * It may for example encode a deadline in case of the EDF scheduler.
+ *
+ * The thread priority control value contained in the scheduler node
+ * (Scheduler_Node::Priority::value) uses the least-significant bit to indicate
+ * if the thread should be appended or prepended to its priority group, see
+ * SCHEDULER_PRIORITY_APPEND().
  */
 typedef uint64_t Priority_Control;
 
diff --git a/cpukit/score/include/rtems/score/scheduler.h b/cpukit/score/include/rtems/score/scheduler.h
index 669f82c48c..a6066c8e4a 100644
--- a/cpukit/score/include/rtems/score/scheduler.h
+++ b/cpukit/score/include/rtems/score/scheduler.h
@@ -334,19 +334,32 @@ extern const Scheduler_Control _Scheduler_Table[];
 #endif
 
 /**
- * @brief Returns the thread priority.
+ * @brief Returns the scheduler internal thread priority mapped by
+ * SCHEDULER_PRIORITY_MAP().
  *
  * @param[in] scheduler Unused.
- * @param[in] priority The thread priority.
+ * @param[in] priority The user visible thread priority.
  *
- * @return priority The thread priority.
+ * @return priority The scheduler internal thread priority.
  */
 Priority_Control _Scheduler_default_Map_priority(
   const Scheduler_Control *scheduler,
   Priority_Control         priority
 );
 
-#define _Scheduler_default_Unmap_priority _Scheduler_default_Map_priority
+/**
+ * @brief Returns the user visible thread priority unmapped by
+ * SCHEDULER_PRIORITY_UNMAP().
+ *
+ * @param[in] scheduler Unused.
+ * @param[in] priority The scheduler internal thread priority.
+ *
+ * @return priority The user visible thread priority.
+ */
+Priority_Control _Scheduler_default_Unmap_priority(
+  const Scheduler_Control *scheduler,
+  Priority_Control         priority
+);
 
 #if defined(RTEMS_SMP)
   /**
diff --git a/cpukit/score/include/rtems/score/scheduleredfimpl.h b/cpukit/score/include/rtems/score/scheduleredfimpl.h
index 94a78fcff5..f6bd7d8384 100644
--- a/cpukit/score/include/rtems/score/scheduleredfimpl.h
+++ b/cpukit/score/include/rtems/score/scheduleredfimpl.h
@@ -79,7 +79,7 @@ RTEMS_INLINE_ROUTINE bool _Scheduler_EDF_Less(
   return prio_left < prio_right;
 }
 
-RTEMS_INLINE_ROUTINE bool _Scheduler_EDF_Less_or_equal(
+RTEMS_INLINE_ROUTINE bool _Scheduler_EDF_Priority_less_equal(
   const void        *left,
   const RBTree_Node *right
 )
@@ -101,28 +101,14 @@ RTEMS_INLINE_ROUTINE bool _Scheduler_EDF_Less_or_equal(
 RTEMS_INLINE_ROUTINE void _Scheduler_EDF_Enqueue(
   Scheduler_EDF_Context *context,
   Scheduler_EDF_Node    *node,
-  Priority_Control       priority
+  Priority_Control       insert_priority
 )
 {
   _RBTree_Insert_inline(
     &context->Ready,
     &node->Node,
-    &priority,
-    _Scheduler_EDF_Less
-  );
-}
-
-RTEMS_INLINE_ROUTINE void _Scheduler_EDF_Enqueue_first(
-  Scheduler_EDF_Context *context,
-  Scheduler_EDF_Node    *node,
-  Priority_Control       priority
-)
-{
-  _RBTree_Insert_inline(
-    &context->Ready,
-    &node->Node,
-    &priority,
-    _Scheduler_EDF_Less_or_equal
+    &insert_priority,
+    _Scheduler_EDF_Priority_less_equal
   );
 }
 
diff --git a/cpukit/score/include/rtems/score/schedulerimpl.h b/cpukit/score/include/rtems/score/schedulerimpl.h
index ba04ec9492..10c12242a9 100644
--- a/cpukit/score/include/rtems/score/schedulerimpl.h
+++ b/cpukit/score/include/rtems/score/schedulerimpl.h
@@ -37,6 +37,36 @@ extern "C" {
 /**@{**/
 
 /**
+ * @brief Maps a priority value to support the append indicator.
+ */
+#define SCHEDULER_PRIORITY_MAP( priority ) ( ( priority ) << 1 )
+
+/**
+ * @brief Returns the plain priority value.
+ */
+#define SCHEDULER_PRIORITY_UNMAP( priority ) ( ( priority ) >> 1 )
+
+/**
+ * @brief Clears the priority append indicator bit.
+ */
+#define SCHEDULER_PRIORITY_PURIFY( priority )  \
+  ( ( priority ) & ~( (Priority_Control) SCHEDULER_PRIORITY_APPEND_FLAG ) )
+
+/**
+ * @brief Returns the priority control with the append indicator bit set.
+ */
+#define SCHEDULER_PRIORITY_APPEND( priority )  \
+  ( ( priority ) | SCHEDULER_PRIORITY_APPEND_FLAG )
+
+/**
+ * @brief Returns true, if the item should be appended to its priority group,
+ * otherwise returns false and the item should be prepended to its priority
+ * group.
+ */
+#define SCHEDULER_PRIORITY_IS_APPEND( priority ) \
+  ( ( ( priority ) & SCHEDULER_PRIORITY_APPEND_FLAG ) != 0 )
+
+/**
  *  @brief Initializes the scheduler to the policy chosen by the user.
  *
  *  This routine initializes the scheduler to the policy chosen by the user
diff --git a/cpukit/score/include/rtems/score/schedulernode.h b/cpukit/score/include/rtems/score/schedulernode.h
index 1474b0c13c..d62e983853 100644
--- a/cpukit/score/include/rtems/score/schedulernode.h
+++ b/cpukit/score/include/rtems/score/schedulernode.h
@@ -175,6 +175,12 @@ struct Scheduler_Node {
      *
      * The producer of this value is _Thread_Change_priority().  The consumer
      * is the scheduler via the unblock and update priority operations.
+     *
+     * This priority control consists of two parts.  One part is the plain
+     * priority value (most-significant 63 bits).  The other part is the
+     * least-significant bit which indicates if the thread should be appended
+     * (bit set) or prepended (bit cleared) to its priority group, see
+     * SCHEDULER_PRIORITY_APPEND().
      */
     Priority_Control value;
 
@@ -184,13 +190,6 @@ struct Scheduler_Node {
      */
     SMP_sequence_lock_Control Lock;
 #endif
-
-    /**
-     * @brief In case a priority update is necessary and this is true, then
-     * enqueue the thread as the first of its priority group, otherwise enqueue
-     * the thread as the last of its priority group.
-     */
-    bool prepend_it;
   } Priority;
 };
 
diff --git a/cpukit/score/include/rtems/score/schedulernodeimpl.h b/cpukit/score/include/rtems/score/schedulernodeimpl.h
index 9ac0334979..8997b3f218 100644
--- a/cpukit/score/include/rtems/score/schedulernodeimpl.h
+++ b/cpukit/score/include/rtems/score/schedulernodeimpl.h
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2014, 2016 embedded brains GmbH.  All rights reserved.
+ * Copyright (c) 2014, 2017 embedded brains GmbH.  All rights reserved.
  *
  *  embedded brains GmbH
  *  Dornierstr. 4
@@ -30,6 +30,12 @@ extern "C" {
 #define SCHEDULER_NODE_OF_WAIT_PRIORITY( node ) \
   RTEMS_CONTAINER_OF( node, Scheduler_Node, Wait.Priority )
 
+/**
+ * @brief Priority append indicator for the priority control used for the
+ * scheduler node priority.
+ */
+#define SCHEDULER_PRIORITY_APPEND_FLAG 1
+
 RTEMS_INLINE_ROUTINE void _Scheduler_Node_do_initialize(
   const struct _Scheduler_Control *scheduler,
   Scheduler_Node                  *node,
@@ -40,7 +46,6 @@ RTEMS_INLINE_ROUTINE void _Scheduler_Node_do_initialize(
   node->owner = the_thread;
 
   node->Priority.value = priority;
-  node->Priority.prepend_it = false;
 
 #if defined(RTEMS_SMP)
   _Chain_Initialize_node( &node->Thread.Wait_node );
@@ -69,12 +74,10 @@ RTEMS_INLINE_ROUTINE Thread_Control *_Scheduler_Node_get_owner(
 }
 
 RTEMS_INLINE_ROUTINE Priority_Control _Scheduler_Node_get_priority(
-  Scheduler_Node *node,
-  bool           *prepend_it_p
+  Scheduler_Node *node
 )
 {
   Priority_Control priority;
-  bool             prepend_it;
 
 #if defined(RTEMS_SMP)
   unsigned int     seq;
@@ -84,14 +87,11 @@ RTEMS_INLINE_ROUTINE Priority_Control _Scheduler_Node_get_priority(
 #endif
 
     priority = node->Priority.value;
-    prepend_it = node->Priority.prepend_it;
 
 #if defined(RTEMS_SMP)
   } while ( _SMP_sequence_lock_Read_retry( &node->Priority.Lock, seq ) );
 #endif
 
-  *prepend_it_p = prepend_it;
-
   return priority;
 }
 
@@ -107,8 +107,8 @@ RTEMS_INLINE_ROUTINE void _Scheduler_Node_set_priority(
   seq = _SMP_sequence_lock_Write_begin( &node->Priority.Lock );
 #endif
 
+  new_priority |= ( prepend_it ? 0 : SCHEDULER_PRIORITY_APPEND_FLAG );
   node->Priority.value = new_priority;
-  node->Priority.prepend_it = prepend_it;
 
 #if defined(RTEMS_SMP)
   _SMP_sequence_lock_Write_end( &node->Priority.Lock, seq );
diff --git a/cpukit/score/include/rtems/score/schedulerpriorityimpl.h b/cpukit/score/include/rtems/score/schedulerpriorityimpl.h
index 68c61c16f3..354065fac4 100644
--- a/cpukit/score/include/rtems/score/schedulerpriorityimpl.h
+++ b/cpukit/score/include/rtems/score/schedulerpriorityimpl.h
@@ -216,18 +216,18 @@ RTEMS_INLINE_ROUTINE void _Scheduler_priority_Schedule_body(
  */
 RTEMS_INLINE_ROUTINE void _Scheduler_priority_Ready_queue_update(
   Scheduler_priority_Ready_queue *ready_queue,
-  Priority_Control                new_priority,
+  unsigned int                    new_priority,
   Priority_bit_map_Control       *bit_map,
   Chain_Control                  *ready_queues
 )
 {
-  ready_queue->current_priority = (unsigned int) new_priority;
+  ready_queue->current_priority = new_priority;
   ready_queue->ready_chain = &ready_queues[ new_priority ];
 
   _Priority_bit_map_Initialize_information(
     bit_map,
     &ready_queue->Priority_map,
-    (unsigned int) new_priority
+    new_priority
   );
 }
 
diff --git a/cpukit/score/include/rtems/score/schedulerprioritysmpimpl.h b/cpukit/score/include/rtems/score/schedulerprioritysmpimpl.h
index 073a7ade06..17d6e552f3 100644
--- a/cpukit/score/include/rtems/score/schedulerprioritysmpimpl.h
+++ b/cpukit/score/include/rtems/score/schedulerprioritysmpimpl.h
@@ -7,7 +7,7 @@
  */
 
 /*
- * Copyright (c) 2013-2014 embedded brains GmbH.  All rights reserved.
+ * Copyright (c) 2013, 2017 embedded brains GmbH.  All rights reserved.
  *
  *  embedded brains GmbH
  *  Dornierstr. 4
@@ -90,7 +90,7 @@ static inline void _Scheduler_priority_SMP_Move_from_ready_to_scheduled(
 {
   Scheduler_priority_SMP_Context *self;
   Scheduler_priority_SMP_Node    *node;
-  Priority_Control                priority;
+  Priority_Control                insert_priority;
 
   self = _Scheduler_priority_SMP_Get_self( context );
   node = _Scheduler_priority_SMP_Node_downcast( ready_to_scheduled );
@@ -100,47 +100,41 @@ static inline void _Scheduler_priority_SMP_Move_from_ready_to_scheduled(
     &node->Ready_queue,
     &self->Bit_map
   );
-  priority = node->Base.priority;
+  insert_priority = _Scheduler_SMP_Node_priority( &node->Base.Base );
+  insert_priority = SCHEDULER_PRIORITY_APPEND( insert_priority );
   _Chain_Insert_ordered_unprotected(
     &self->Base.Scheduled,
     &node->Base.Base.Node.Chain,
-    &priority,
-    _Scheduler_SMP_Insert_priority_fifo_order
+    &insert_priority,
+    _Scheduler_SMP_Priority_less_equal
   );
 }
 
-static inline void _Scheduler_priority_SMP_Insert_ready_lifo(
+static inline void _Scheduler_priority_SMP_Insert_ready(
   Scheduler_Context *context,
-  Scheduler_Node    *thread
-)
-{
-  Scheduler_priority_SMP_Context *self =
-    _Scheduler_priority_SMP_Get_self( context );
-  Scheduler_priority_SMP_Node *node =
-    _Scheduler_priority_SMP_Node_downcast( thread );
-
-  _Scheduler_priority_Ready_queue_enqueue(
-    &node->Base.Base.Node.Chain,
-    &node->Ready_queue,
-    &self->Bit_map
-  );
-}
-
-static inline void _Scheduler_priority_SMP_Insert_ready_fifo(
-  Scheduler_Context *context,
-  Scheduler_Node    *thread
+  Scheduler_Node    *node_base,
+  Priority_Control   insert_priority
 )
 {
-  Scheduler_priority_SMP_Context *self =
-    _Scheduler_priority_SMP_Get_self( context );
-  Scheduler_priority_SMP_Node *node =
-    _Scheduler_priority_SMP_Node_downcast( thread );
+  Scheduler_priority_SMP_Context *self;
+  Scheduler_priority_SMP_Node    *node;
 
-  _Scheduler_priority_Ready_queue_enqueue_first(
-    &node->Base.Base.Node.Chain,
-    &node->Ready_queue,
-    &self->Bit_map
-  );
+  self = _Scheduler_priority_SMP_Get_self( context );
+  node = _Scheduler_priority_SMP_Node_downcast( node_base );
+
+  if ( SCHEDULER_PRIORITY_IS_APPEND( insert_priority ) ) {
+    _Scheduler_priority_Ready_queue_enqueue(
+      &node->Base.Base.Node.Chain,
+      &node->Ready_queue,
+      &self->Bit_map
+    );
+  } else {
+    _Scheduler_priority_Ready_queue_enqueue_first(
+      &node->Base.Base.Node.Chain,
+      &node->Ready_queue,
+      &self->Bit_map
+    );
+  }
 }
 
 static inline void _Scheduler_priority_SMP_Extract_from_ready(
@@ -162,19 +156,20 @@ static inline void _Scheduler_priority_SMP_Extract_from_ready(
 
 static inline void _Scheduler_priority_SMP_Do_update(
   Scheduler_Context *context,
-  Scheduler_Node *node_to_update,
-  Priority_Control new_priority
+  Scheduler_Node    *node_to_update,
+  Priority_Control   new_priority
 )
 {
-  Scheduler_priority_SMP_Context *self =
-    _Scheduler_priority_SMP_Get_self( context );
-  Scheduler_priority_SMP_Node *node =
-    _Scheduler_priority_SMP_Node_downcast( node_to_update );
+  Scheduler_priority_SMP_Context *self;
+  Scheduler_priority_SMP_Node    *node;
+
+  self = _Scheduler_priority_SMP_Get_self( context );
+  node = _Scheduler_priority_SMP_Node_downcast( node_to_update );
 
   _Scheduler_SMP_Node_update_priority( &node->Base, new_priority );
   _Scheduler_priority_Ready_queue_update(
     &node->Ready_queue,
-    new_priority,
+    SCHEDULER_PRIORITY_UNMAP( new_priority ),
     &self->Bit_map,
     &self->Ready[ 0 ]
   );
diff --git a/cpukit/score/include/rtems/score/schedulersimpleimpl.h b/cpukit/score/include/rtems/score/schedulersimpleimpl.h
index ec74cdc586..3891839281 100644
--- a/cpukit/score/include/rtems/score/schedulersimpleimpl.h
+++ b/cpukit/score/include/rtems/score/schedulersimpleimpl.h
@@ -38,65 +38,31 @@ RTEMS_INLINE_ROUTINE Scheduler_simple_Context *
   return (Scheduler_simple_Context *) _Scheduler_Get_context( scheduler );
 }
 
-RTEMS_INLINE_ROUTINE bool _Scheduler_simple_Insert_priority_lifo_order(
+RTEMS_INLINE_ROUTINE bool _Scheduler_simple_Priority_less_equal(
   const void       *to_insert,
   const Chain_Node *next
 )
 {
-  const Priority_Control *priority_to_insert;
-  const Thread_Control   *thread_next;
+  const unsigned int   *priority_to_insert;
+  const Thread_Control *thread_next;
 
-  priority_to_insert = (const Priority_Control *) to_insert;
+  priority_to_insert = (const unsigned int *) to_insert;
   thread_next = (const Thread_Control *) next;
 
   return *priority_to_insert <= _Thread_Get_priority( thread_next );
 }
 
-RTEMS_INLINE_ROUTINE bool _Scheduler_simple_Insert_priority_fifo_order(
-  const void       *to_insert,
-  const Chain_Node *next
-)
-{
-  const Priority_Control *priority_to_insert;
-  const Thread_Control   *thread_next;
-
-  priority_to_insert = (const Priority_Control *) to_insert;
-  thread_next = (const Thread_Control *) next;
-
-  return *priority_to_insert < _Thread_Get_priority( thread_next );
-}
-
-RTEMS_INLINE_ROUTINE void _Scheduler_simple_Insert_priority_lifo(
-  Chain_Control  *chain,
-  Thread_Control *to_insert
-)
-{
-  Priority_Control priority_to_insert;
-
-  priority_to_insert = _Thread_Get_priority( to_insert );
-
-  _Chain_Insert_ordered_unprotected(
-    chain,
-    &to_insert->Object.Node,
-    &priority_to_insert,
-    _Scheduler_simple_Insert_priority_lifo_order
-  );
-}
-
-RTEMS_INLINE_ROUTINE void _Scheduler_simple_Insert_priority_fifo(
+RTEMS_INLINE_ROUTINE void _Scheduler_simple_Insert(
   Chain_Control  *chain,
-  Thread_Control *to_insert
+  Thread_Control *to_insert,
+  unsigned int    insert_priority
 )
 {
-  Priority_Control priority_to_insert;
-
-  priority_to_insert = _Thread_Get_priority( to_insert );
-
   _Chain_Insert_ordered_unprotected(
     chain,
     &to_insert->Object.Node,
-    &priority_to_insert,
-    _Scheduler_simple_Insert_priority_fifo_order
+    &insert_priority,
+    _Scheduler_simple_Priority_less_equal
   );
 }
 
diff --git a/cpukit/score/include/rtems/score/schedulersmpimpl.h b/cpukit/score/include/rtems/score/schedulersmpimpl.h
index 896b1306ab..e152eb0878 100644
--- a/cpukit/score/include/rtems/score/schedulersmpimpl.h
+++ b/cpukit/score/include/rtems/score/schedulersmpimpl.h
@@ -42,8 +42,8 @@ extern "C" {
  * - @ref SCHEDULER_SMP_NODE_READY.
  *
  * State transitions are triggered via basic operations
- * - _Scheduler_SMP_Enqueue_ordered(),
- * - _Scheduler_SMP_Enqueue_scheduled_ordered(), and
+ * - _Scheduler_SMP_Enqueue(),
+ * - _Scheduler_SMP_Enqueue_scheduled(), and
  * - _Scheduler_SMP_Block().
  *
  * @dot
@@ -296,7 +296,8 @@ typedef void ( *Scheduler_SMP_Extract )(
 
 typedef void ( *Scheduler_SMP_Insert )(
   Scheduler_Context *context,
-  Scheduler_Node    *node_to_insert
+  Scheduler_Node    *node_to_insert,
+  Priority_Control   insert_priority
 );
 
 typedef void ( *Scheduler_SMP_Move )(
@@ -324,7 +325,8 @@ typedef void ( *Scheduler_SMP_Set_affinity )(
 
 typedef bool ( *Scheduler_SMP_Enqueue )(
   Scheduler_Context *context,
-  Scheduler_Node    *node_to_enqueue
+  Scheduler_Node    *node_to_enqueue,
+  Priority_Control   priority
 );
 
 typedef void ( *Scheduler_SMP_Allocate_processor )(
@@ -351,7 +353,7 @@ static inline void _Scheduler_SMP_Do_nothing_register_idle(
   (void) cpu;
 }
 
-static inline bool _Scheduler_SMP_Insert_priority_lifo_order(
+static inline bool _Scheduler_SMP_Priority_less_equal(
   const void       *to_insert,
   const Chain_Node *next
 )
@@ -365,20 +367,6 @@ static inline bool _Scheduler_SMP_Insert_priority_lifo_order(
   return *priority_to_insert <= node_next->priority;
 }
 
-static inline bool _Scheduler_SMP_Insert_priority_fifo_order(
-  const void       *to_insert,
-  const Chain_Node *next
-)
-{
-  const Priority_Control   *priority_to_insert;
-  const Scheduler_SMP_Node *node_next;
-
-  priority_to_insert = (const Priority_Control *) to_insert;
-  node_next = (const Scheduler_SMP_Node *) next;
-
-  return *priority_to_insert < node_next->priority;
-}
-
 static inline Scheduler_SMP_Context *_Scheduler_SMP_Get_self(
   Scheduler_Context *context
 )
@@ -637,6 +625,7 @@ static inline Scheduler_Node *_Scheduler_SMP_Get_lowest_scheduled(
 static inline void _Scheduler_SMP_Enqueue_to_scheduled(
   Scheduler_Context                *context,
   Scheduler_Node                   *node,
+  Priority_Control                  priority,
   Scheduler_Node                   *lowest_scheduled,
   Scheduler_SMP_Insert              insert_scheduled,
   Scheduler_SMP_Move                move_from_scheduled_to_ready,
@@ -660,7 +649,7 @@ static inline void _Scheduler_SMP_Enqueue_to_scheduled(
       allocate_processor
     );
 
-    ( *insert_scheduled )( context, node );
+    ( *insert_scheduled )( context, node, priority );
     ( *move_from_scheduled_to_ready )( context, lowest_scheduled );
 
     _Scheduler_Release_idle_thread(
@@ -675,7 +664,7 @@ static inline void _Scheduler_SMP_Enqueue_to_scheduled(
     );
     _Scheduler_SMP_Node_change_state( node, SCHEDULER_SMP_NODE_SCHEDULED );
 
-    ( *insert_scheduled )( context, node );
+    ( *insert_scheduled )( context, node, priority );
     ( *move_from_scheduled_to_ready )( context, lowest_scheduled );
 
     _Scheduler_Exchange_idle_thread(
@@ -696,6 +685,7 @@ static inline void _Scheduler_SMP_Enqueue_to_scheduled(
  *
  * @param[in] context The scheduler instance context.
  * @param[in] node The node to enqueue.
+ * @param[in] priority The node insert priority.
  * @param[in] order The order function.
  * @param[in] insert_ready Function to insert a node into the set of ready
  *   nodes.
@@ -710,9 +700,10 @@ static inline void _Scheduler_SMP_Enqueue_to_scheduled(
  * @param[in] allocate_processor Function to allocate a processor to a node
  *   based on the rules of the scheduler.
  */
-static inline bool _Scheduler_SMP_Enqueue_ordered(
+static inline bool _Scheduler_SMP_Enqueue(
   Scheduler_Context                  *context,
   Scheduler_Node                     *node,
+  Priority_Control                    insert_priority,
   Chain_Node_order                    order,
   Scheduler_SMP_Insert                insert_ready,
   Scheduler_SMP_Insert                insert_scheduled,
@@ -721,17 +712,16 @@ static inline bool _Scheduler_SMP_Enqueue_ordered(
   Scheduler_SMP_Allocate_processor    allocate_processor
 )
 {
-  bool              needs_help;
-  Scheduler_Node   *lowest_scheduled;
-  Priority_Control  node_priority;
+  bool            needs_help;
+  Scheduler_Node *lowest_scheduled;
 
   lowest_scheduled = ( *get_lowest_scheduled )( context, node );
-  node_priority = _Scheduler_SMP_Node_priority( node );
 
-  if ( ( *order )( &node_priority, &lowest_scheduled->Node.Chain ) ) {
+  if ( ( *order )( &insert_priority, &lowest_scheduled->Node.Chain ) ) {
     _Scheduler_SMP_Enqueue_to_scheduled(
       context,
       node,
+      insert_priority,
       lowest_scheduled,
       insert_scheduled,
       move_from_scheduled_to_ready,
@@ -739,7 +729,7 @@ static inline bool _Scheduler_SMP_Enqueue_ordered(
     );
     needs_help = false;
   } else {
-    ( *insert_ready )( context, node );
+    ( *insert_ready )( context, node, insert_priority );
     needs_help = true;
   }
 
@@ -765,9 +755,10 @@ static inline bool _Scheduler_SMP_Enqueue_ordered(
  * @param[in] allocate_processor Function to allocate a processor to a node
  *   based on the rules of the scheduler.
  */
-static inline bool _Scheduler_SMP_Enqueue_scheduled_ordered(
+static inline bool _Scheduler_SMP_Enqueue_scheduled(
   Scheduler_Context                *context,
-  Scheduler_Node                   *node,
+  Scheduler_Node                   *const node,
+  Priority_Control                  insert_priority,
   Chain_Node_order                  order,
   Scheduler_SMP_Extract             extract_from_ready,
   Scheduler_SMP_Get_highest_ready   get_highest_ready,
@@ -780,10 +771,8 @@ static inline bool _Scheduler_SMP_Enqueue_scheduled_ordered(
   while ( true ) {
     Scheduler_Node                   *highest_ready;
     Scheduler_Try_to_schedule_action  action;
-    Priority_Control                  node_priority;
 
     highest_ready = ( *get_highest_ready )( context, node );
-    node_priority = _Scheduler_SMP_Node_priority( node );
 
     /*
      * The node has been extracted from the scheduled chain.  We have to place
@@ -791,9 +780,9 @@ static inline bool _Scheduler_SMP_Enqueue_scheduled_ordered(
      */
     if (
       node->sticky_level > 0
-        && ( *order )( &node_priority, &highest_ready->Node.Chain )
+        && ( *order )( &insert_priority, &highest_ready->Node.Chain )
     ) {
-      ( *insert_scheduled )( context, node );
+      ( *insert_scheduled )( context, node, insert_priority );
 
       if ( _Scheduler_Node_get_idle( node ) != NULL ) {
         Thread_Control   *owner;
@@ -839,7 +828,7 @@ static inline bool _Scheduler_SMP_Enqueue_scheduled_ordered(
         allocate_processor
       );
 
-      ( *insert_ready )( context, node );
+      ( *insert_ready )( context, node, insert_priority );
       ( *move_from_ready_to_scheduled )( context, highest_ready );
 
       idle = _Scheduler_Release_idle_thread(
@@ -855,7 +844,7 @@ static inline bool _Scheduler_SMP_Enqueue_scheduled_ordered(
         SCHEDULER_SMP_NODE_SCHEDULED
       );
 
-      ( *insert_ready )( context, node );
+      ( *insert_ready )( context, node, insert_priority );
       ( *move_from_ready_to_scheduled )( context, highest_ready );
 
       _Scheduler_Exchange_idle_thread(
@@ -1033,7 +1022,7 @@ static inline void _Scheduler_SMP_Unblock(
   Thread_Control        *thread,
   Scheduler_Node        *node,
   Scheduler_SMP_Update   update,
-  Scheduler_SMP_Enqueue  enqueue_fifo
+  Scheduler_SMP_Enqueue  enqueue
 )
 {
   Scheduler_SMP_Node_state  node_state;
@@ -1049,21 +1038,22 @@ static inline void _Scheduler_SMP_Unblock(
   );
 
   if ( unblock ) {
-    Priority_Control new_priority;
-    bool             prepend_it;
+    Priority_Control priority;
     bool             needs_help;
 
-    new_priority = _Scheduler_Node_get_priority( node, &prepend_it );
-    (void) prepend_it;
+    priority = _Scheduler_Node_get_priority( node );
+    priority = SCHEDULER_PRIORITY_PURIFY( priority );
 
-    if ( new_priority != _Scheduler_SMP_Node_priority( node ) ) {
-      ( *update )( context, node, new_priority );
+    if ( priority != _Scheduler_SMP_Node_priority( node ) ) {
+      ( *update )( context, node, priority );
     }
 
     if ( node_state == SCHEDULER_SMP_NODE_BLOCKED ) {
-      _Scheduler_SMP_Node_change_state( node, SCHEDULER_SMP_NODE_READY );
+      Priority_Control insert_priority;
 
-      needs_help = ( *enqueue_fifo )( context, node );
+      _Scheduler_SMP_Node_change_state( node, SCHEDULER_SMP_NODE_READY );
+      insert_priority = SCHEDULER_PRIORITY_APPEND( priority );
+      needs_help = ( *enqueue )( context, node, insert_priority );
     } else {
       _Assert( node_state == SCHEDULER_SMP_NODE_READY );
       _Assert( node->sticky_level > 0 );
@@ -1083,20 +1073,19 @@ static inline void _Scheduler_SMP_Update_priority(
   Scheduler_Node             *node,
   Scheduler_SMP_Extract       extract_from_ready,
   Scheduler_SMP_Update        update,
-  Scheduler_SMP_Enqueue       enqueue_fifo,
-  Scheduler_SMP_Enqueue       enqueue_lifo,
-  Scheduler_SMP_Enqueue       enqueue_scheduled_fifo,
-  Scheduler_SMP_Enqueue       enqueue_scheduled_lifo,
+  Scheduler_SMP_Enqueue       enqueue,
+  Scheduler_SMP_Enqueue       enqueue_scheduled,
   Scheduler_SMP_Ask_for_help  ask_for_help
 )
 {
-  Priority_Control         new_priority;
-  bool                     prepend_it;
+  Priority_Control         priority;
+  Priority_Control         insert_priority;
   Scheduler_SMP_Node_state node_state;
 
-  new_priority = _Scheduler_Node_get_priority( node, &prepend_it );
+  insert_priority = _Scheduler_Node_get_priority( node );
+  priority = SCHEDULER_PRIORITY_PURIFY( insert_priority );
 
-  if ( new_priority == _Scheduler_SMP_Node_priority( node ) ) {
+  if ( priority == _Scheduler_SMP_Node_priority( node ) ) {
     if ( _Thread_Is_ready( thread ) ) {
       ( *ask_for_help )( context, thread, node );
     }
@@ -1108,26 +1097,14 @@ static inline void _Scheduler_SMP_Update_priority(
 
   if ( node_state == SCHEDULER_SMP_NODE_SCHEDULED ) {
     _Scheduler_SMP_Extract_from_scheduled( node );
-
-    ( *update )( context, node, new_priority );
-
-    if ( prepend_it ) {
-      ( *enqueue_scheduled_lifo )( context, node );
-    } else {
-      ( *enqueue_scheduled_fifo )( context, node );
-    }
+    ( *update )( context, node, priority );
+    ( *enqueue_scheduled )( context, node, insert_priority );
   } else if ( node_state == SCHEDULER_SMP_NODE_READY ) {
     ( *extract_from_ready )( context, node );
-
-    ( *update )( context, node, new_priority );
-
-    if ( prepend_it ) {
-      ( *enqueue_lifo )( context, node );
-    } else {
-      ( *enqueue_fifo )( context, node );
-    }
+    ( *update )( context, node, priority );
+    ( *enqueue )( context, node, insert_priority );
   } else {
-    ( *update )( context, node, new_priority );
+    ( *update )( context, node, priority );
 
     if ( _Thread_Is_ready( thread ) ) {
       ( *ask_for_help )( context, thread, node );
@@ -1140,23 +1117,26 @@ static inline void _Scheduler_SMP_Yield(
   Thread_Control        *thread,
   Scheduler_Node        *node,
   Scheduler_SMP_Extract  extract_from_ready,
-  Scheduler_SMP_Enqueue  enqueue_fifo,
-  Scheduler_SMP_Enqueue  enqueue_scheduled_fifo
+  Scheduler_SMP_Enqueue  enqueue,
+  Scheduler_SMP_Enqueue  enqueue_scheduled
 )
 {
   bool                     needs_help;
   Scheduler_SMP_Node_state node_state;
+  Priority_Control         insert_priority;
 
   node_state = _Scheduler_SMP_Node_state( node );
+  insert_priority = _Scheduler_SMP_Node_priority( node );
+  insert_priority = SCHEDULER_PRIORITY_APPEND( insert_priority );
 
   if ( node_state == SCHEDULER_SMP_NODE_SCHEDULED ) {
     _Scheduler_SMP_Extract_from_scheduled( node );
-    ( *enqueue_scheduled_fifo )( context, node );
+    ( *enqueue_scheduled )( context, node, insert_priority );
     needs_help = false;
   } else if ( node_state == SCHEDULER_SMP_NODE_READY ) {
     ( *extract_from_ready )( context, node );
 
-    needs_help = ( *enqueue_fifo )( context, node );
+    needs_help = ( *enqueue )( context, node, insert_priority );
   } else {
     needs_help = true;
   }
@@ -1166,41 +1146,21 @@ static inline void _Scheduler_SMP_Yield(
   }
 }
 
-static inline void _Scheduler_SMP_Insert_scheduled_lifo(
-  Scheduler_Context *context,
-  Scheduler_Node    *node_to_insert
-)
-{
-  Scheduler_SMP_Context *self;
-  Priority_Control       priority_to_insert;
-
-  self = _Scheduler_SMP_Get_self( context );
-  priority_to_insert = _Scheduler_SMP_Node_priority( node_to_insert );
-
-  _Chain_Insert_ordered_unprotected(
-    &self->Scheduled,
-    &node_to_insert->Node.Chain,
-    &priority_to_insert,
-    _Scheduler_SMP_Insert_priority_lifo_order
-  );
-}
-
-static inline void _Scheduler_SMP_Insert_scheduled_fifo(
+static inline void _Scheduler_SMP_Insert_scheduled(
   Scheduler_Context *context,
-  Scheduler_Node    *node_to_insert
+  Scheduler_Node    *node_to_insert,
+  Priority_Control   priority_to_insert
 )
 {
   Scheduler_SMP_Context *self;
-  Priority_Control       priority_to_insert;
 
   self = _Scheduler_SMP_Get_self( context );
-  priority_to_insert = _Scheduler_SMP_Node_priority( node_to_insert );
 
   _Chain_Insert_ordered_unprotected(
     &self->Scheduled,
     &node_to_insert->Node.Chain,
     &priority_to_insert,
-    _Scheduler_SMP_Insert_priority_fifo_order
+    _Scheduler_SMP_Priority_less_equal
   );
 }
 
@@ -1230,11 +1190,11 @@ static inline bool _Scheduler_SMP_Ask_for_help(
     node_state = _Scheduler_SMP_Node_state( node );
 
     if ( node_state == SCHEDULER_SMP_NODE_BLOCKED ) {
-      Priority_Control node_priority;
+      Priority_Control insert_priority;
 
-      node_priority = _Scheduler_SMP_Node_priority( node );
+      insert_priority = _Scheduler_SMP_Node_priority( node );
 
-      if ( ( *order )( &node_priority, &lowest_scheduled->Node.Chain ) ) {
+      if ( ( *order )( &insert_priority, &lowest_scheduled->Node.Chain ) ) {
         _Thread_Scheduler_cancel_need_for_help(
           thread,
           _Thread_Get_CPU( thread )
@@ -1249,7 +1209,7 @@ static inline bool _Scheduler_SMP_Ask_for_help(
           allocate_processor
         );
 
-        ( *insert_scheduled )( context, node );
+        ( *insert_scheduled )( context, node, insert_priority );
         ( *move_from_scheduled_to_ready )( context, lowest_scheduled );
 
         _Scheduler_Release_idle_thread(
@@ -1261,7 +1221,7 @@ static inline bool _Scheduler_SMP_Ask_for_help(
       } else {
         _Thread_Scheduler_release_critical( thread, &lock_context );
         _Scheduler_SMP_Node_change_state( node, SCHEDULER_SMP_NODE_READY );
-        ( *insert_ready )( context, node );
+        ( *insert_ready )( context, node, insert_priority );
         success = false;
       }
     } else if ( node_state == SCHEDULER_SMP_NODE_SCHEDULED ) {
@@ -1384,7 +1344,7 @@ static inline void _Scheduler_SMP_Add_processor(
   Scheduler_Context           *context,
   Thread_Control              *idle,
   Scheduler_SMP_Has_ready      has_ready,
-  Scheduler_SMP_Enqueue        enqueue_scheduled_fifo,
+  Scheduler_SMP_Enqueue        enqueue_scheduled,
   Scheduler_SMP_Register_idle  register_idle
 )
 {
@@ -1399,7 +1359,11 @@ static inline void _Scheduler_SMP_Add_processor(
   ( *register_idle )( context, node, _Thread_Get_CPU( idle ) );
 
   if ( ( *has_ready )( &self->Base ) ) {
-    ( *enqueue_scheduled_fifo )( &self->Base, node );
+    Priority_Control insert_priority;
+
+    insert_priority = _Scheduler_SMP_Node_priority( node );
+    insert_priority = SCHEDULER_PRIORITY_APPEND( insert_priority );
+    ( *enqueue_scheduled )( &self->Base, node, insert_priority );
   } else {
     _Chain_Append_unprotected( &self->Scheduled, &node->Node.Chain );
   }
@@ -1409,7 +1373,7 @@ static inline Thread_Control *_Scheduler_SMP_Remove_processor(
   Scheduler_Context     *context,
   Per_CPU_Control       *cpu,
   Scheduler_SMP_Extract  extract_from_ready,
-  Scheduler_SMP_Enqueue  enqueue_fifo
+  Scheduler_SMP_Enqueue  enqueue
 )
 {
   Scheduler_SMP_Context *self;
@@ -1451,7 +1415,11 @@ static inline Thread_Control *_Scheduler_SMP_Remove_processor(
     );
 
     if ( !_Chain_Is_empty( &self->Scheduled ) ) {
-      ( *enqueue_fifo )( context, victim_node );
+      Priority_Control insert_priority;
+
+      insert_priority = _Scheduler_SMP_Node_priority( victim_node );
+      insert_priority = SCHEDULER_PRIORITY_APPEND( insert_priority );
+      ( *enqueue )( context, victim_node, insert_priority );
     }
   } else {
     _Assert( victim_owner == victim_user );
@@ -1472,13 +1440,16 @@ static inline void _Scheduler_SMP_Set_affinity(
   Scheduler_SMP_Extract            extract_from_ready,
   Scheduler_SMP_Get_highest_ready  get_highest_ready,
   Scheduler_SMP_Move               move_from_ready_to_scheduled,
-  Scheduler_SMP_Enqueue            enqueue_fifo,
+  Scheduler_SMP_Enqueue            enqueue,
   Scheduler_SMP_Allocate_processor allocate_processor
 )
 {
   Scheduler_SMP_Node_state node_state;
+  Priority_Control         insert_priority;
 
   node_state = _Scheduler_SMP_Node_state( node );
+  insert_priority = _Scheduler_SMP_Node_priority( node );
+  insert_priority = SCHEDULER_PRIORITY_APPEND( insert_priority );
 
   if ( node_state == SCHEDULER_SMP_NODE_SCHEDULED ) {
     _Scheduler_SMP_Extract_from_scheduled( node );
@@ -1492,11 +1463,11 @@ static inline void _Scheduler_SMP_Set_affinity(
       allocate_processor
     );
     ( *set_affinity )( context, node, arg );
-    ( *enqueue_fifo )( context, node );
+    ( *enqueue )( context, node, insert_priority );
   } else if ( node_state == SCHEDULER_SMP_NODE_READY ) {
     ( *extract_from_ready )( context, node );
     ( *set_affinity )( context, node, arg );
-    ( *enqueue_fifo )( context, node );
+    ( *enqueue )( context, node, insert_priority );
   } else {
     ( *set_affinity )( context, node, arg );
   }
diff --git a/cpukit/score/src/schedulercbsunblock.c b/cpukit/score/src/schedulercbsunblock.c
index 403435eeb1..9b7a0ca424 100644
--- a/cpukit/score/src/schedulercbsunblock.c
+++ b/cpukit/score/src/schedulercbsunblock.c
@@ -34,12 +34,11 @@ void _Scheduler_CBS_Unblock(
   Scheduler_CBS_Node   *the_node;
   Scheduler_CBS_Server *serv_info;
   Priority_Control      priority;
-  bool                  prepend_it;
 
   the_node = _Scheduler_CBS_Node_downcast( node );
   serv_info = the_node->cbs_server;
-  priority = _Scheduler_Node_get_priority( &the_node->Base.Base, &prepend_it );
-  (void) prepend_it;
+  priority = _Scheduler_Node_get_priority( &the_node->Base.Base );
+  priority = SCHEDULER_PRIORITY_PURIFY( priority );
 
   /*
    * Late unblock rule for deadline-driven tasks. The remaining time to
diff --git a/cpukit/score/src/schedulerdefaultmappriority.c b/cpukit/score/src/schedulerdefaultmappriority.c
index 37a600011e..228549f20d 100644
--- a/cpukit/score/src/schedulerdefaultmappriority.c
+++ b/cpukit/score/src/schedulerdefaultmappriority.c
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2016 embedded brains GmbH
+ * Copyright (c) 2016, 2017 embedded brains GmbH
  *
  * The license and distribution terms for this file may be
  * found in the file LICENSE in this distribution or at
@@ -10,12 +10,20 @@
 #include "config.h"
 #endif
 
-#include <rtems/score/scheduler.h>
+#include <rtems/score/schedulerimpl.h>
 
 Priority_Control _Scheduler_default_Map_priority(
   const Scheduler_Control *scheduler,
   Priority_Control         priority
 )
 {
-  return priority;
+  return SCHEDULER_PRIORITY_MAP( priority );
+}
+
+Priority_Control _Scheduler_default_Unmap_priority(
+  const Scheduler_Control *scheduler,
+  Priority_Control         priority
+)
+{
+  return SCHEDULER_PRIORITY_UNMAP( priority );
 }
diff --git a/cpukit/score/src/scheduleredfchangepriority.c b/cpukit/score/src/scheduleredfchangepriority.c
index 23382973cc..d3d1f94cbf 100644
--- a/cpukit/score/src/scheduleredfchangepriority.c
+++ b/cpukit/score/src/scheduleredfchangepriority.c
@@ -29,7 +29,7 @@ void _Scheduler_EDF_Update_priority(
   Scheduler_EDF_Context *context;
   Scheduler_EDF_Node    *the_node;
   Priority_Control       priority;
-  bool                   prepend_it;
+  Priority_Control       insert_priority;
 
   if ( !_Thread_Is_ready( the_thread ) ) {
     /* Nothing to do */
@@ -37,7 +37,8 @@ void _Scheduler_EDF_Update_priority(
   }
 
   the_node = _Scheduler_EDF_Node_downcast( node );
-  priority = _Scheduler_Node_get_priority( &the_node->Base, &prepend_it );
+  insert_priority = _Scheduler_Node_get_priority( &the_node->Base );
+  priority = SCHEDULER_PRIORITY_PURIFY( insert_priority );
 
   if ( priority == the_node->priority ) {
     /* Nothing to do */
@@ -48,12 +49,6 @@ void _Scheduler_EDF_Update_priority(
   context = _Scheduler_EDF_Get_context( scheduler );
 
   _Scheduler_EDF_Extract( context, the_node );
-
-  if ( prepend_it ) {
-    _Scheduler_EDF_Enqueue_first( context, the_node, priority );
-  } else {
-    _Scheduler_EDF_Enqueue( context, the_node, priority );
-  }
-
+  _Scheduler_EDF_Enqueue( context, the_node, insert_priority );
   _Scheduler_EDF_Schedule_body( scheduler, the_thread, false );
 }
diff --git a/cpukit/score/src/scheduleredfreleasejob.c b/cpukit/score/src/scheduleredfreleasejob.c
index 068a0db7a3..d7865ff5fb 100644
--- a/cpukit/score/src/scheduleredfreleasejob.c
+++ b/cpukit/score/src/scheduleredfreleasejob.c
@@ -25,7 +25,7 @@ Priority_Control _Scheduler_EDF_Map_priority(
   Priority_Control         priority
 )
 {
-  return SCHEDULER_EDF_PRIO_MSB | priority;
+  return SCHEDULER_EDF_PRIO_MSB | SCHEDULER_PRIORITY_MAP( priority );
 }
 
 Priority_Control _Scheduler_EDF_Unmap_priority(
@@ -33,7 +33,7 @@ Priority_Control _Scheduler_EDF_Unmap_priority(
   Priority_Control         priority
 )
 {
-  return priority & ~SCHEDULER_EDF_PRIO_MSB;
+  return SCHEDULER_PRIORITY_UNMAP( priority & ~SCHEDULER_EDF_PRIO_MSB );
 }
 
 void _Scheduler_EDF_Release_job(
@@ -48,7 +48,16 @@ void _Scheduler_EDF_Release_job(
 
   _Thread_Wait_acquire_critical( the_thread, queue_context );
 
-  _Priority_Node_set_priority( priority_node, deadline );
+  /*
+   * There is no integer overflow problem here due to the
+   * SCHEDULER_PRIORITY_MAP().  The deadline is in clock ticks.  With the
+   * minimum clock tick interval of 1us, the uptime is limited to about 146235
+   * years.
+   */
+  _Priority_Node_set_priority(
+    priority_node,
+    SCHEDULER_PRIORITY_MAP( deadline )
+  );
 
   if ( _Priority_Node_is_active( priority_node ) ) {
     _Thread_Priority_changed(
diff --git a/cpukit/score/src/scheduleredfsmp.c b/cpukit/score/src/scheduleredfsmp.c
index badee44e2e..102a33d4f7 100644
--- a/cpukit/score/src/scheduleredfsmp.c
+++ b/cpukit/score/src/scheduleredfsmp.c
@@ -39,26 +39,7 @@ _Scheduler_EDF_SMP_Node_downcast( Scheduler_Node *node )
   return (Scheduler_EDF_SMP_Node *) node;
 }
 
-static inline bool _Scheduler_EDF_SMP_Less(
-  const void        *left,
-  const RBTree_Node *right
-)
-{
-  const Priority_Control   *the_left;
-  const Scheduler_SMP_Node *the_right;
-  Priority_Control          prio_left;
-  Priority_Control          prio_right;
-
-  the_left = left;
-  the_right = RTEMS_CONTAINER_OF( right, Scheduler_SMP_Node, Base.Node.RBTree );
-
-  prio_left = *the_left;
-  prio_right = the_right->priority;
-
-  return prio_left < prio_right;
-}
-
-static inline bool _Scheduler_EDF_SMP_Less_or_equal(
+static inline bool _Scheduler_EDF_SMP_Priority_less_equal(
   const void        *left,
   const RBTree_Node *right
 )
@@ -254,20 +235,21 @@ static inline Scheduler_Node *_Scheduler_EDF_SMP_Get_lowest_scheduled(
 static inline void _Scheduler_EDF_SMP_Insert_ready(
   Scheduler_Context *context,
   Scheduler_Node    *node_base,
-  int                generation_index,
-  bool            ( *less )( const void *, const RBTree_Node * )
+  Priority_Control   insert_priority
 )
 {
   Scheduler_EDF_SMP_Context     *self;
   Scheduler_EDF_SMP_Node        *node;
   uint32_t                       rqi;
   Scheduler_EDF_SMP_Ready_queue *ready_queue;
+  int                            generation_index;
   int                            increment;
   int64_t                        generation;
 
   self = _Scheduler_EDF_SMP_Get_self( context );
   node = _Scheduler_EDF_SMP_Node_downcast( node_base );
   rqi = node->ready_queue_index;
+  generation_index = SCHEDULER_PRIORITY_IS_APPEND( insert_priority );
   increment = ( generation_index << 1 ) - 1;
   ready_queue = &self->Ready[ rqi ];
 
@@ -279,8 +261,8 @@ static inline void _Scheduler_EDF_SMP_Insert_ready(
   _RBTree_Insert_inline(
     &ready_queue->Queue,
     &node->Base.Base.Node.RBTree,
-    &node->Base.priority,
-    less
+    &insert_priority,
+    _Scheduler_EDF_SMP_Priority_less_equal
   );
 
   if ( rqi != 0 && _Chain_Is_node_off_chain( &ready_queue->Node ) ) {
@@ -327,12 +309,14 @@ static inline void _Scheduler_EDF_SMP_Move_from_scheduled_to_ready(
   Scheduler_Node    *scheduled_to_ready
 )
 {
+  Priority_Control insert_priority;
+
   _Chain_Extract_unprotected( &scheduled_to_ready->Node.Chain );
+  insert_priority = _Scheduler_SMP_Node_priority( scheduled_to_ready );
   _Scheduler_EDF_SMP_Insert_ready(
     context,
     scheduled_to_ready,
-    1,
-    _Scheduler_EDF_SMP_Less
+    insert_priority
   );
 }
 
@@ -341,33 +325,15 @@ static inline void _Scheduler_EDF_SMP_Move_from_ready_to_scheduled(
   Scheduler_Node    *ready_to_scheduled
 )
 {
-  _Scheduler_EDF_SMP_Extract_from_ready( context, ready_to_scheduled );
-  _Scheduler_SMP_Insert_scheduled_fifo( context, ready_to_scheduled );
-}
+  Priority_Control insert_priority;
 
-static inline void _Scheduler_EDF_SMP_Insert_ready_lifo(
-  Scheduler_Context *context,
-  Scheduler_Node    *node_to_insert
-)
-{
-  _Scheduler_EDF_SMP_Insert_ready(
-    context,
-    node_to_insert,
-    0,
-    _Scheduler_EDF_SMP_Less_or_equal
-  );
-}
-
-static inline void _Scheduler_EDF_SMP_Insert_ready_fifo(
-  Scheduler_Context *context,
-  Scheduler_Node    *node_to_insert
-)
-{
-  _Scheduler_EDF_SMP_Insert_ready(
+  _Scheduler_EDF_SMP_Extract_from_ready( context, ready_to_scheduled );
+  insert_priority = _Scheduler_SMP_Node_priority( ready_to_scheduled );
+  insert_priority = SCHEDULER_PRIORITY_APPEND( insert_priority );
+  _Scheduler_SMP_Insert_scheduled(
     context,
-    node_to_insert,
-    1,
-    _Scheduler_EDF_SMP_Less
+    ready_to_scheduled,
+    insert_priority
   );
 }
 
@@ -444,103 +410,45 @@ void _Scheduler_EDF_SMP_Block(
   );
 }
 
-static inline bool _Scheduler_EDF_SMP_Enqueue_ordered(
-  Scheduler_Context    *context,
-  Scheduler_Node       *node,
-  Chain_Node_order      order,
-  Scheduler_SMP_Insert  insert_ready,
-  Scheduler_SMP_Insert  insert_scheduled
+static inline bool _Scheduler_EDF_SMP_Enqueue(
+  Scheduler_Context *context,
+  Scheduler_Node    *node,
+  Priority_Control   insert_priority
 )
 {
-  return _Scheduler_SMP_Enqueue_ordered(
+  return _Scheduler_SMP_Enqueue(
     context,
     node,
-    order,
-    insert_ready,
-    insert_scheduled,
+    insert_priority,
+    _Scheduler_SMP_Priority_less_equal,
+    _Scheduler_EDF_SMP_Insert_ready,
+    _Scheduler_SMP_Insert_scheduled,
     _Scheduler_EDF_SMP_Move_from_scheduled_to_ready,
     _Scheduler_EDF_SMP_Get_lowest_scheduled,
     _Scheduler_EDF_SMP_Allocate_processor
   );
 }
 
-static inline bool _Scheduler_EDF_SMP_Enqueue_lifo(
+static inline bool _Scheduler_EDF_SMP_Enqueue_scheduled(
   Scheduler_Context *context,
-  Scheduler_Node    *node
-)
-{
-  return _Scheduler_EDF_SMP_Enqueue_ordered(
-    context,
-    node,
-    _Scheduler_SMP_Insert_priority_lifo_order,
-    _Scheduler_EDF_SMP_Insert_ready_lifo,
-    _Scheduler_SMP_Insert_scheduled_lifo
-  );
-}
-
-static inline bool _Scheduler_EDF_SMP_Enqueue_fifo(
-  Scheduler_Context *context,
-  Scheduler_Node    *node
-)
-{
-  return _Scheduler_EDF_SMP_Enqueue_ordered(
-    context,
-    node,
-    _Scheduler_SMP_Insert_priority_fifo_order,
-    _Scheduler_EDF_SMP_Insert_ready_fifo,
-    _Scheduler_SMP_Insert_scheduled_fifo
-  );
-}
-
-static inline bool _Scheduler_EDF_SMP_Enqueue_scheduled_ordered(
-  Scheduler_Context *context,
-  Scheduler_Node *node,
-  Chain_Node_order order,
-  Scheduler_SMP_Insert insert_ready,
-  Scheduler_SMP_Insert insert_scheduled
+  Scheduler_Node    *node,
+  Priority_Control   insert_priority
 )
 {
-  return _Scheduler_SMP_Enqueue_scheduled_ordered(
+  return _Scheduler_SMP_Enqueue_scheduled(
     context,
     node,
-    order,
+    insert_priority,
+    _Scheduler_SMP_Priority_less_equal,
     _Scheduler_EDF_SMP_Extract_from_ready,
     _Scheduler_EDF_SMP_Get_highest_ready,
-    insert_ready,
-    insert_scheduled,
+    _Scheduler_EDF_SMP_Insert_ready,
+    _Scheduler_SMP_Insert_scheduled,
     _Scheduler_EDF_SMP_Move_from_ready_to_scheduled,
     _Scheduler_EDF_SMP_Allocate_processor
   );
 }
 
-static inline bool _Scheduler_EDF_SMP_Enqueue_scheduled_lifo(
-  Scheduler_Context *context,
-  Scheduler_Node *node
-)
-{
-  return _Scheduler_EDF_SMP_Enqueue_scheduled_ordered(
-    context,
-    node,
-    _Scheduler_SMP_Insert_priority_lifo_order,
-    _Scheduler_EDF_SMP_Insert_ready_lifo,
-    _Scheduler_SMP_Insert_scheduled_lifo
-  );
-}
-
-static inline bool _Scheduler_EDF_SMP_Enqueue_scheduled_fifo(
-  Scheduler_Context *context,
-  Scheduler_Node *node
-)
-{
-  return _Scheduler_EDF_SMP_Enqueue_scheduled_ordered(
-    context,
-    node,
-    _Scheduler_SMP_Insert_priority_fifo_order,
-    _Scheduler_EDF_SMP_Insert_ready_fifo,
-    _Scheduler_SMP_Insert_scheduled_fifo
-  );
-}
-
 void _Scheduler_EDF_SMP_Unblock(
   const Scheduler_Control *scheduler,
   Thread_Control          *thread,
@@ -554,7 +462,7 @@ void _Scheduler_EDF_SMP_Unblock(
     thread,
     node,
     _Scheduler_EDF_SMP_Do_update,
-    _Scheduler_EDF_SMP_Enqueue_fifo
+    _Scheduler_EDF_SMP_Enqueue
   );
 }
 
@@ -568,9 +476,9 @@ static inline bool _Scheduler_EDF_SMP_Do_ask_for_help(
     context,
     the_thread,
     node,
-    _Scheduler_SMP_Insert_priority_lifo_order,
-    _Scheduler_EDF_SMP_Insert_ready_lifo,
-    _Scheduler_SMP_Insert_scheduled_lifo,
+    _Scheduler_SMP_Priority_less_equal,
+    _Scheduler_EDF_SMP_Insert_ready,
+    _Scheduler_SMP_Insert_scheduled,
     _Scheduler_EDF_SMP_Move_from_scheduled_to_ready,
     _Scheduler_EDF_SMP_Get_lowest_scheduled,
     _Scheduler_EDF_SMP_Allocate_processor
@@ -591,10 +499,8 @@ void _Scheduler_EDF_SMP_Update_priority(
     node,
     _Scheduler_EDF_SMP_Extract_from_ready,
     _Scheduler_EDF_SMP_Do_update,
-    _Scheduler_EDF_SMP_Enqueue_fifo,
-    _Scheduler_EDF_SMP_Enqueue_lifo,
-    _Scheduler_EDF_SMP_Enqueue_scheduled_fifo,
-    _Scheduler_EDF_SMP_Enqueue_scheduled_lifo,
+    _Scheduler_EDF_SMP_Enqueue,
+    _Scheduler_EDF_SMP_Enqueue_scheduled,
     _Scheduler_EDF_SMP_Do_ask_for_help
   );
 }
@@ -672,7 +578,7 @@ void _Scheduler_EDF_SMP_Add_processor(
     context,
     idle,
     _Scheduler_EDF_SMP_Has_ready,
-    _Scheduler_EDF_SMP_Enqueue_scheduled_fifo,
+    _Scheduler_EDF_SMP_Enqueue_scheduled,
     _Scheduler_EDF_SMP_Register_idle
   );
 }
@@ -688,7 +594,7 @@ Thread_Control *_Scheduler_EDF_SMP_Remove_processor(
     context,
     cpu,
     _Scheduler_EDF_SMP_Extract_from_ready,
-    _Scheduler_EDF_SMP_Enqueue_fifo
+    _Scheduler_EDF_SMP_Enqueue
   );
 }
 
@@ -705,8 +611,8 @@ void _Scheduler_EDF_SMP_Yield(
     thread,
     node,
     _Scheduler_EDF_SMP_Extract_from_ready,
-    _Scheduler_EDF_SMP_Enqueue_fifo,
-    _Scheduler_EDF_SMP_Enqueue_scheduled_fifo
+    _Scheduler_EDF_SMP_Enqueue,
+    _Scheduler_EDF_SMP_Enqueue_scheduled
   );
 }
 
@@ -777,7 +683,7 @@ bool _Scheduler_EDF_SMP_Set_affinity(
     _Scheduler_EDF_SMP_Extract_from_ready,
     _Scheduler_EDF_SMP_Get_highest_ready,
     _Scheduler_EDF_SMP_Move_from_ready_to_scheduled,
-    _Scheduler_EDF_SMP_Enqueue_fifo,
+    _Scheduler_EDF_SMP_Enqueue,
     _Scheduler_EDF_SMP_Allocate_processor
   );
 
diff --git a/cpukit/score/src/scheduleredfunblock.c b/cpukit/score/src/scheduleredfunblock.c
index 29355d04fa..91295f511c 100644
--- a/cpukit/score/src/scheduleredfunblock.c
+++ b/cpukit/score/src/scheduleredfunblock.c
@@ -31,15 +31,16 @@ void _Scheduler_EDF_Unblock(
   Scheduler_EDF_Context *context;
   Scheduler_EDF_Node    *the_node;
   Priority_Control       priority;
-  bool                   prepend_it;
+  Priority_Control       insert_priority;
 
   context = _Scheduler_EDF_Get_context( scheduler );
   the_node = _Scheduler_EDF_Node_downcast( node );
-  priority = _Scheduler_Node_get_priority( &the_node->Base, &prepend_it );
-  (void) prepend_it;
+  priority = _Scheduler_Node_get_priority( &the_node->Base );
+  priority = SCHEDULER_PRIORITY_PURIFY( priority );
+  insert_priority = SCHEDULER_PRIORITY_APPEND( priority );
 
   the_node->priority = priority;
-  _Scheduler_EDF_Enqueue( context, the_node, priority );
+  _Scheduler_EDF_Enqueue( context, the_node, insert_priority );
 
   /*
    *  If the thread that was unblocked is more important than the heir,
diff --git a/cpukit/score/src/schedulerpriority.c b/cpukit/score/src/schedulerpriority.c
index ddfd973e0a..5ac16a49a1 100644
--- a/cpukit/score/src/schedulerpriority.c
+++ b/cpukit/score/src/schedulerpriority.c
@@ -19,7 +19,6 @@
 #endif
 
 #include <rtems/score/schedulerpriorityimpl.h>
-#include <rtems/score/wkspace.h>
 
 void _Scheduler_priority_Initialize( const Scheduler_Control *scheduler )
 {
@@ -49,7 +48,7 @@ void _Scheduler_priority_Node_initialize(
   the_node = _Scheduler_priority_Node_downcast( node );
   _Scheduler_priority_Ready_queue_update(
     &the_node->Ready_queue,
-    priority,
+    SCHEDULER_PRIORITY_UNMAP( priority ),
     &context->Bit_map,
     &context->Ready[ 0 ]
   );
diff --git a/cpukit/score/src/schedulerpriorityaffinitysmp.c b/cpukit/score/src/schedulerpriorityaffinitysmp.c
index 72b4ffb600..4808c84c3f 100644
--- a/cpukit/score/src/schedulerpriorityaffinitysmp.c
+++ b/cpukit/score/src/schedulerpriorityaffinitysmp.c
@@ -39,22 +39,13 @@
  *  + _Scheduler_priority_SMP_Do_update
  */
 
-static bool _Scheduler_priority_affinity_SMP_Insert_priority_lifo_order(
+static bool _Scheduler_priority_affinity_SMP_Priority_less_equal(
   const void       *to_insert,
   const Chain_Node *next
 )
 {
   return next != NULL
-    && _Scheduler_SMP_Insert_priority_lifo_order( to_insert, next );
-}
-
-static bool _Scheduler_priority_affinity_SMP_Insert_priority_fifo_order(
-  const void       *to_insert,
-  const Chain_Node *next
-)
-{
-  return next != NULL
-    && _Scheduler_SMP_Insert_priority_fifo_order( to_insert, next );
+    && _Scheduler_SMP_Priority_less_equal( to_insert, next );
 }
 
 static Scheduler_priority_affinity_SMP_Node *
@@ -242,19 +233,21 @@ static Scheduler_Node * _Scheduler_priority_affinity_SMP_Get_lowest_scheduled(
 /*
  * This method is unique to this scheduler because it must pass
  * _Scheduler_priority_affinity_SMP_Get_lowest_scheduled into
- * _Scheduler_SMP_Enqueue_ordered.
+ * _Scheduler_SMP_Enqueue.
  */
 static bool _Scheduler_priority_affinity_SMP_Enqueue_fifo(
   Scheduler_Context *context,
-  Scheduler_Node    *node
+  Scheduler_Node    *node,
+  Priority_Control   insert_priority
 )
 {
-  return _Scheduler_SMP_Enqueue_ordered(
+  return _Scheduler_SMP_Enqueue(
     context,
     node,
-    _Scheduler_priority_affinity_SMP_Insert_priority_fifo_order,
-    _Scheduler_priority_SMP_Insert_ready_fifo,
-    _Scheduler_SMP_Insert_scheduled_fifo,
+    insert_priority,
+    _Scheduler_priority_affinity_SMP_Priority_less_equal,
+    _Scheduler_priority_SMP_Insert_ready,
+    _Scheduler_SMP_Insert_scheduled,
     _Scheduler_priority_SMP_Move_from_scheduled_to_ready,
     _Scheduler_priority_affinity_SMP_Get_lowest_scheduled,
     _Scheduler_SMP_Allocate_processor_exact
@@ -280,6 +273,7 @@ static void _Scheduler_priority_affinity_SMP_Check_for_migrations(
 
   while (1) {
     Priority_Control lowest_scheduled_priority;
+    Priority_Control insert_priority;
 
     if ( _Priority_bit_map_Is_empty( &self->Bit_map ) ) {
       /* Nothing to do */
@@ -312,7 +306,7 @@ static void _Scheduler_priority_affinity_SMP_Check_for_migrations(
       _Scheduler_SMP_Node_priority( lowest_scheduled );
 
     if (
-      _Scheduler_SMP_Insert_priority_lifo_order(
+      _Scheduler_SMP_Priority_less_equal(
         &lowest_scheduled_priority,
         &highest_ready->Node.Chain
       )
@@ -326,11 +320,14 @@ static void _Scheduler_priority_affinity_SMP_Check_for_migrations(
      */
 
     _Scheduler_priority_SMP_Extract_from_ready( context, highest_ready );
+    insert_priority = _Scheduler_SMP_Node_priority( highest_ready );
+    insert_priority = SCHEDULER_PRIORITY_APPEND( insert_priority );
     _Scheduler_SMP_Enqueue_to_scheduled(
       context,
       highest_ready,
+      insert_priority,
       lowest_scheduled,
-      _Scheduler_SMP_Insert_scheduled_fifo,
+      _Scheduler_SMP_Insert_scheduled,
       _Scheduler_priority_SMP_Move_from_scheduled_to_ready,
       _Scheduler_SMP_Allocate_processor_exact
     );
@@ -364,22 +361,21 @@ void _Scheduler_priority_affinity_SMP_Unblock(
 
 /*
  *  This is unique to this scheduler because it passes scheduler specific
- *  get_lowest_scheduled helper to _Scheduler_SMP_Enqueue_ordered.
+ *  get_lowest_scheduled helper to _Scheduler_SMP_Enqueue.
  */
-static bool _Scheduler_priority_affinity_SMP_Enqueue_ordered(
-  Scheduler_Context     *context,
-  Scheduler_Node        *node,
-  Chain_Node_order       order,
-  Scheduler_SMP_Insert   insert_ready,
-  Scheduler_SMP_Insert   insert_scheduled
+static bool _Scheduler_priority_affinity_SMP_Enqueue(
+  Scheduler_Context *context,
+  Scheduler_Node    *node,
+  Priority_Control   insert_priority
 )
 {
-  return _Scheduler_SMP_Enqueue_ordered(
+  return _Scheduler_SMP_Enqueue(
     context,
     node,
-    order,
-    insert_ready,
-    insert_scheduled,
+    insert_priority,
+    _Scheduler_priority_affinity_SMP_Priority_less_equal,
+    _Scheduler_priority_SMP_Insert_ready,
+    _Scheduler_SMP_Insert_scheduled,
     _Scheduler_priority_SMP_Move_from_scheduled_to_ready,
     _Scheduler_priority_affinity_SMP_Get_lowest_scheduled,
     _Scheduler_SMP_Allocate_processor_exact
@@ -387,88 +383,30 @@ static bool _Scheduler_priority_affinity_SMP_Enqueue_ordered(
 }
 
 /*
- *  This is unique to this scheduler because it is on the path
- *  to _Scheduler_priority_affinity_SMP_Enqueue_ordered() which
- *  invokes a scheduler unique get_lowest_scheduled helper.
- */
-static bool _Scheduler_priority_affinity_SMP_Enqueue_lifo(
-  Scheduler_Context *context,
-  Scheduler_Node    *node
-)
-{
-  return _Scheduler_priority_affinity_SMP_Enqueue_ordered(
-    context,
-    node,
-    _Scheduler_priority_affinity_SMP_Insert_priority_lifo_order,
-    _Scheduler_priority_SMP_Insert_ready_lifo,
-    _Scheduler_SMP_Insert_scheduled_lifo
-  );
-}
-
-/*
  * This method is unique to this scheduler because it must
- * invoke _Scheduler_SMP_Enqueue_scheduled_ordered() with
+ * invoke _Scheduler_SMP_Enqueue_scheduled() with
  * this scheduler's get_highest_ready() helper.
  */
-static bool _Scheduler_priority_affinity_SMP_Enqueue_scheduled_ordered(
-  Scheduler_Context    *context,
-  Scheduler_Node       *node,
-  Chain_Node_order      order,
-  Scheduler_SMP_Insert  insert_ready,
-  Scheduler_SMP_Insert  insert_scheduled
+static bool _Scheduler_priority_affinity_SMP_Enqueue_scheduled(
+  Scheduler_Context *context,
+  Scheduler_Node    *node,
+  Priority_Control   insert_priority
 )
 {
-  return _Scheduler_SMP_Enqueue_scheduled_ordered(
+  return _Scheduler_SMP_Enqueue_scheduled(
     context,
     node,
-    order,
+    insert_priority,
+    _Scheduler_SMP_Priority_less_equal,
     _Scheduler_priority_SMP_Extract_from_ready,
     _Scheduler_priority_affinity_SMP_Get_highest_ready,
-    insert_ready,
-    insert_scheduled,
+    _Scheduler_priority_SMP_Insert_ready,
+    _Scheduler_SMP_Insert_scheduled,
     _Scheduler_priority_SMP_Move_from_ready_to_scheduled,
     _Scheduler_SMP_Allocate_processor_exact
   );
 }
 
-/*
- *  This is unique to this scheduler because it is on the path
- *  to _Scheduler_priority_affinity_SMP_Enqueue_scheduled__ordered() which
- *  invokes a scheduler unique get_lowest_scheduled helper.
- */
-static bool _Scheduler_priority_affinity_SMP_Enqueue_scheduled_lifo(
-  Scheduler_Context *context,
-  Scheduler_Node    *node
-)
-{
-  return _Scheduler_priority_affinity_SMP_Enqueue_scheduled_ordered(
-    context,
-    node,
-    _Scheduler_SMP_Insert_priority_lifo_order,
-    _Scheduler_priority_SMP_Insert_ready_lifo,
-    _Scheduler_SMP_Insert_scheduled_lifo
-  );
-}
-
-/*
- *  This is unique to this scheduler because it is on the path
- *  to _Scheduler_priority_affinity_SMP_Enqueue_scheduled__ordered() which
- *  invokes a scheduler unique get_lowest_scheduled helper.
- */
-static bool _Scheduler_priority_affinity_SMP_Enqueue_scheduled_fifo(
-  Scheduler_Context *context,
-  Scheduler_Node    *node
-)
-{
-  return _Scheduler_priority_affinity_SMP_Enqueue_scheduled_ordered(
-    context,
-    node,
-    _Scheduler_SMP_Insert_priority_fifo_order,
-    _Scheduler_priority_SMP_Insert_ready_fifo,
-    _Scheduler_SMP_Insert_scheduled_fifo
-  );
-}
-
 static bool _Scheduler_priority_affinity_SMP_Do_ask_for_help(
   Scheduler_Context *context,
   Thread_Control    *the_thread,
@@ -479,9 +417,9 @@ static bool _Scheduler_priority_affinity_SMP_Do_ask_for_help(
     context,
     the_thread,
     node,
-    _Scheduler_SMP_Insert_priority_lifo_order,
-    _Scheduler_priority_SMP_Insert_ready_lifo,
-    _Scheduler_SMP_Insert_scheduled_lifo,
+    _Scheduler_SMP_Priority_less_equal,
+    _Scheduler_priority_SMP_Insert_ready,
+    _Scheduler_SMP_Insert_scheduled,
     _Scheduler_priority_SMP_Move_from_scheduled_to_ready,
     _Scheduler_SMP_Get_lowest_scheduled,
     _Scheduler_SMP_Allocate_processor_lazy
@@ -502,10 +440,8 @@ void _Scheduler_priority_affinity_SMP_Update_priority(
     node,
     _Scheduler_priority_SMP_Extract_from_ready,
     _Scheduler_priority_SMP_Do_update,
-    _Scheduler_priority_affinity_SMP_Enqueue_fifo,
-    _Scheduler_priority_affinity_SMP_Enqueue_lifo,
-    _Scheduler_priority_affinity_SMP_Enqueue_scheduled_fifo,
-    _Scheduler_priority_affinity_SMP_Enqueue_scheduled_lifo,
+    _Scheduler_priority_affinity_SMP_Enqueue,
+    _Scheduler_priority_affinity_SMP_Enqueue_scheduled,
     _Scheduler_priority_affinity_SMP_Do_ask_for_help
   );
 
@@ -574,7 +510,7 @@ void _Scheduler_priority_affinity_SMP_Add_processor(
     context,
     idle,
     _Scheduler_priority_SMP_Has_ready,
-    _Scheduler_priority_affinity_SMP_Enqueue_scheduled_fifo,
+    _Scheduler_priority_affinity_SMP_Enqueue_scheduled,
     _Scheduler_SMP_Do_nothing_register_idle
   );
 }
@@ -590,7 +526,7 @@ Thread_Control *_Scheduler_priority_affinity_SMP_Remove_processor(
     context,
     cpu,
     _Scheduler_priority_SMP_Extract_from_ready,
-    _Scheduler_priority_affinity_SMP_Enqueue_fifo
+    _Scheduler_priority_affinity_SMP_Enqueue
   );
 }
 
diff --git a/cpukit/score/src/schedulerprioritychangepriority.c b/cpukit/score/src/schedulerprioritychangepriority.c
index eb640fe683..6af475a8d6 100644
--- a/cpukit/score/src/schedulerprioritychangepriority.c
+++ b/cpukit/score/src/schedulerprioritychangepriority.c
@@ -29,8 +29,8 @@ void _Scheduler_priority_Update_priority(
 {
   Scheduler_priority_Context *context;
   Scheduler_priority_Node    *the_node;
-  unsigned int                priority;
-  bool                        prepend_it;
+  unsigned int                new_priority;
+  unsigned int                unmapped_priority;
 
   if ( !_Thread_Is_ready( the_thread ) ) {
     /* Nothing to do */
@@ -38,10 +38,11 @@ void _Scheduler_priority_Update_priority(
   }
 
   the_node = _Scheduler_priority_Node_downcast( node );
-  priority = (unsigned int )
-    _Scheduler_Node_get_priority( &the_node->Base, &prepend_it );
+  new_priority = (unsigned int)
+    _Scheduler_Node_get_priority( &the_node->Base );
+  unmapped_priority = SCHEDULER_PRIORITY_UNMAP( new_priority );
 
-  if ( priority == the_node->Ready_queue.current_priority ) {
+  if ( unmapped_priority == the_node->Ready_queue.current_priority ) {
     /* Nothing to do */
     return;
   }
@@ -56,19 +57,19 @@ void _Scheduler_priority_Update_priority(
 
   _Scheduler_priority_Ready_queue_update(
     &the_node->Ready_queue,
-    priority,
+    unmapped_priority,
     &context->Bit_map,
     &context->Ready[ 0 ]
   );
 
-  if ( prepend_it ) {
-    _Scheduler_priority_Ready_queue_enqueue_first(
+  if ( SCHEDULER_PRIORITY_IS_APPEND( new_priority ) ) {
+    _Scheduler_priority_Ready_queue_enqueue(
       &the_thread->Object.Node,
       &the_node->Ready_queue,
       &context->Bit_map
     );
   } else {
-    _Scheduler_priority_Ready_queue_enqueue(
+    _Scheduler_priority_Ready_queue_enqueue_first(
       &the_thread->Object.Node,
       &the_node->Ready_queue,
       &context->Bit_map
diff --git a/cpukit/score/src/schedulerprioritysmp.c b/cpukit/score/src/schedulerprioritysmp.c
index 071a4218f3..205d3257ca 100644
--- a/cpukit/score/src/schedulerprioritysmp.c
+++ b/cpukit/score/src/schedulerprioritysmp.c
@@ -68,7 +68,7 @@ void _Scheduler_priority_SMP_Node_initialize(
   self = _Scheduler_priority_SMP_Get_self( context );
   _Scheduler_priority_Ready_queue_update(
     &the_node->Ready_queue,
-    priority,
+    SCHEDULER_PRIORITY_UNMAP( priority ),
     &self->Bit_map,
     &self->Ready[ 0 ]
   );
@@ -109,103 +109,45 @@ void _Scheduler_priority_SMP_Block(
   );
 }
 
-static bool _Scheduler_priority_SMP_Enqueue_ordered(
-  Scheduler_Context    *context,
-  Scheduler_Node       *node,
-  Chain_Node_order      order,
-  Scheduler_SMP_Insert  insert_ready,
-  Scheduler_SMP_Insert  insert_scheduled
+static bool _Scheduler_priority_SMP_Enqueue(
+  Scheduler_Context *context,
+  Scheduler_Node    *node,
+  Priority_Control   insert_priority
 )
 {
-  return _Scheduler_SMP_Enqueue_ordered(
+  return _Scheduler_SMP_Enqueue(
     context,
     node,
-    order,
-    insert_ready,
-    insert_scheduled,
+    insert_priority,
+    _Scheduler_SMP_Priority_less_equal,
+    _Scheduler_priority_SMP_Insert_ready,
+    _Scheduler_SMP_Insert_scheduled,
     _Scheduler_priority_SMP_Move_from_scheduled_to_ready,
     _Scheduler_SMP_Get_lowest_scheduled,
     _Scheduler_SMP_Allocate_processor_lazy
   );
 }
 
-static bool _Scheduler_priority_SMP_Enqueue_lifo(
-  Scheduler_Context *context,
-  Scheduler_Node    *node
-)
-{
-  return _Scheduler_priority_SMP_Enqueue_ordered(
-    context,
-    node,
-    _Scheduler_SMP_Insert_priority_lifo_order,
-    _Scheduler_priority_SMP_Insert_ready_lifo,
-    _Scheduler_SMP_Insert_scheduled_lifo
-  );
-}
-
-static bool _Scheduler_priority_SMP_Enqueue_fifo(
+static bool _Scheduler_priority_SMP_Enqueue_scheduled(
   Scheduler_Context *context,
-  Scheduler_Node    *node
+  Scheduler_Node    *node,
+  Priority_Control   insert_priority
 )
 {
-  return _Scheduler_priority_SMP_Enqueue_ordered(
+  return _Scheduler_SMP_Enqueue_scheduled(
     context,
     node,
-    _Scheduler_SMP_Insert_priority_fifo_order,
-    _Scheduler_priority_SMP_Insert_ready_fifo,
-    _Scheduler_SMP_Insert_scheduled_fifo
-  );
-}
-
-static bool _Scheduler_priority_SMP_Enqueue_scheduled_ordered(
-  Scheduler_Context *context,
-  Scheduler_Node *node,
-  Chain_Node_order order,
-  Scheduler_SMP_Insert insert_ready,
-  Scheduler_SMP_Insert insert_scheduled
-)
-{
-  return _Scheduler_SMP_Enqueue_scheduled_ordered(
-    context,
-    node,
-    order,
+    insert_priority,
+    _Scheduler_SMP_Priority_less_equal,
     _Scheduler_priority_SMP_Extract_from_ready,
     _Scheduler_priority_SMP_Get_highest_ready,
-    insert_ready,
-    insert_scheduled,
+    _Scheduler_priority_SMP_Insert_ready,
+    _Scheduler_SMP_Insert_scheduled,
     _Scheduler_priority_SMP_Move_from_ready_to_scheduled,
     _Scheduler_SMP_Allocate_processor_lazy
   );
 }
 
-static bool _Scheduler_priority_SMP_Enqueue_scheduled_lifo(
-  Scheduler_Context *context,
-  Scheduler_Node *node
-)
-{
-  return _Scheduler_priority_SMP_Enqueue_scheduled_ordered(
-    context,
-    node,
-    _Scheduler_SMP_Insert_priority_lifo_order,
-    _Scheduler_priority_SMP_Insert_ready_lifo,
-    _Scheduler_SMP_Insert_scheduled_lifo
-  );
-}
-
-static bool _Scheduler_priority_SMP_Enqueue_scheduled_fifo(
-  Scheduler_Context *context,
-  Scheduler_Node *node
-)
-{
-  return _Scheduler_priority_SMP_Enqueue_scheduled_ordered(
-    context,
-    node,
-    _Scheduler_SMP_Insert_priority_fifo_order,
-    _Scheduler_priority_SMP_Insert_ready_fifo,
-    _Scheduler_SMP_Insert_scheduled_fifo
-  );
-}
-
 void _Scheduler_priority_SMP_Unblock(
   const Scheduler_Control *scheduler,
   Thread_Control          *thread,
@@ -219,7 +161,7 @@ void _Scheduler_priority_SMP_Unblock(
     thread,
     node,
     _Scheduler_priority_SMP_Do_update,
-    _Scheduler_priority_SMP_Enqueue_fifo
+    _Scheduler_priority_SMP_Enqueue
   );
 }
 
@@ -233,9 +175,9 @@ static bool _Scheduler_priority_SMP_Do_ask_for_help(
     context,
     the_thread,
     node,
-    _Scheduler_SMP_Insert_priority_lifo_order,
-    _Scheduler_priority_SMP_Insert_ready_lifo,
-    _Scheduler_SMP_Insert_scheduled_lifo,
+    _Scheduler_SMP_Priority_less_equal,
+    _Scheduler_priority_SMP_Insert_ready,
+    _Scheduler_SMP_Insert_scheduled,
     _Scheduler_priority_SMP_Move_from_scheduled_to_ready,
     _Scheduler_SMP_Get_lowest_scheduled,
     _Scheduler_SMP_Allocate_processor_lazy
@@ -256,10 +198,8 @@ void _Scheduler_priority_SMP_Update_priority(
     node,
     _Scheduler_priority_SMP_Extract_from_ready,
     _Scheduler_priority_SMP_Do_update,
-    _Scheduler_priority_SMP_Enqueue_fifo,
-    _Scheduler_priority_SMP_Enqueue_lifo,
-    _Scheduler_priority_SMP_Enqueue_scheduled_fifo,
-    _Scheduler_priority_SMP_Enqueue_scheduled_lifo,
+    _Scheduler_priority_SMP_Enqueue,
+    _Scheduler_priority_SMP_Enqueue_scheduled,
     _Scheduler_priority_SMP_Do_ask_for_help
   );
 }
@@ -323,7 +263,7 @@ void _Scheduler_priority_SMP_Add_processor(
     context,
     idle,
     _Scheduler_priority_SMP_Has_ready,
-    _Scheduler_priority_SMP_Enqueue_scheduled_fifo,
+    _Scheduler_priority_SMP_Enqueue_scheduled,
     _Scheduler_SMP_Do_nothing_register_idle
   );
 }
@@ -339,7 +279,7 @@ Thread_Control *_Scheduler_priority_SMP_Remove_processor(
     context,
     cpu,
     _Scheduler_priority_SMP_Extract_from_ready,
-    _Scheduler_priority_SMP_Enqueue_fifo
+    _Scheduler_priority_SMP_Enqueue
   );
 }
 
@@ -356,7 +296,7 @@ void _Scheduler_priority_SMP_Yield(
     thread,
     node,
     _Scheduler_priority_SMP_Extract_from_ready,
-    _Scheduler_priority_SMP_Enqueue_fifo,
-    _Scheduler_priority_SMP_Enqueue_scheduled_fifo
+    _Scheduler_priority_SMP_Enqueue,
+    _Scheduler_priority_SMP_Enqueue_scheduled
   );
 }
diff --git a/cpukit/score/src/schedulerpriorityunblock.c b/cpukit/score/src/schedulerpriorityunblock.c
index 42ba4de98f..784bc58611 100644
--- a/cpukit/score/src/schedulerpriorityunblock.c
+++ b/cpukit/score/src/schedulerpriorityunblock.c
@@ -31,18 +31,17 @@ void _Scheduler_priority_Unblock (
   Scheduler_priority_Context *context;
   Scheduler_priority_Node    *the_node;
   unsigned int                priority;
-  bool                        prepend_it;
+  unsigned int                unmapped_priority;
 
   context = _Scheduler_priority_Get_context( scheduler );
   the_node = _Scheduler_priority_Node_downcast( node );
-  priority = (unsigned int )
-    _Scheduler_Node_get_priority( &the_node->Base, &prepend_it );
-  (void) prepend_it;
+  priority = (unsigned int ) _Scheduler_Node_get_priority( &the_node->Base );
+  unmapped_priority = SCHEDULER_PRIORITY_UNMAP( priority );
 
-  if ( priority != the_node->Ready_queue.current_priority ) {
+  if ( unmapped_priority != the_node->Ready_queue.current_priority ) {
     _Scheduler_priority_Ready_queue_update(
       &the_node->Ready_queue,
-      priority,
+      unmapped_priority,
       &context->Bit_map,
       &context->Ready[ 0 ]
     );
diff --git a/cpukit/score/src/schedulersimplechangepriority.c b/cpukit/score/src/schedulersimplechangepriority.c
index 8253a01421..c2c60a5f01 100644
--- a/cpukit/score/src/schedulersimplechangepriority.c
+++ b/cpukit/score/src/schedulersimplechangepriority.c
@@ -28,7 +28,7 @@ void _Scheduler_simple_Update_priority(
 )
 {
   Scheduler_simple_Context *context;
-  bool                      prepend_it;
+  unsigned int              new_priority;
 
   if ( !_Thread_Is_ready( the_thread ) ) {
     /* Nothing to do */
@@ -36,15 +36,9 @@ void _Scheduler_simple_Update_priority(
   }
 
   context = _Scheduler_simple_Get_context( scheduler );
-  _Scheduler_Node_get_priority( node, &prepend_it );
+  new_priority = (unsigned int ) _Scheduler_Node_get_priority( node );
 
   _Scheduler_simple_Extract( scheduler, the_thread, node );
-
-  if ( prepend_it ) {
-    _Scheduler_simple_Insert_priority_lifo( &context->Ready, the_thread );
-  } else {
-    _Scheduler_simple_Insert_priority_fifo( &context->Ready, the_thread );
-  }
-
+  _Scheduler_simple_Insert( &context->Ready, the_thread, new_priority );
   _Scheduler_simple_Schedule_body( scheduler, the_thread, false );
 }
diff --git a/cpukit/score/src/schedulersimplesmp.c b/cpukit/score/src/schedulersimplesmp.c
index df08a19eab..4ab4987c3a 100644
--- a/cpukit/score/src/schedulersimplesmp.c
+++ b/cpukit/score/src/schedulersimplesmp.c
@@ -99,17 +99,17 @@ static void _Scheduler_simple_SMP_Move_from_scheduled_to_ready(
 )
 {
   Scheduler_simple_SMP_Context *self;
-  Priority_Control              priority_to_insert;
+  Priority_Control              insert_priority;
 
   self = _Scheduler_simple_SMP_Get_self( context );
-  priority_to_insert = _Scheduler_SMP_Node_priority( scheduled_to_ready );
 
   _Chain_Extract_unprotected( &scheduled_to_ready->Node.Chain );
+  insert_priority = _Scheduler_SMP_Node_priority( scheduled_to_ready );
   _Chain_Insert_ordered_unprotected(
     &self->Ready,
     &scheduled_to_ready->Node.Chain,
-    &priority_to_insert,
-    _Scheduler_SMP_Insert_priority_lifo_order
+    &insert_priority,
+    _Scheduler_SMP_Priority_less_equal
   );
 }
 
@@ -119,55 +119,36 @@ static void _Scheduler_simple_SMP_Move_from_ready_to_scheduled(
 )
 {
   Scheduler_simple_SMP_Context *self;
-  Priority_Control              priority_to_insert;
+  Priority_Control              insert_priority;
 
   self = _Scheduler_simple_SMP_Get_self( context );
-  priority_to_insert = _Scheduler_SMP_Node_priority( ready_to_scheduled );
 
   _Chain_Extract_unprotected( &ready_to_scheduled->Node.Chain );
+  insert_priority = _Scheduler_SMP_Node_priority( ready_to_scheduled );
+  insert_priority = SCHEDULER_PRIORITY_APPEND( insert_priority );
   _Chain_Insert_ordered_unprotected(
     &self->Base.Scheduled,
     &ready_to_scheduled->Node.Chain,
-    &priority_to_insert,
-    _Scheduler_SMP_Insert_priority_fifo_order
+    &insert_priority,
+    _Scheduler_SMP_Priority_less_equal
   );
 }
 
-static void _Scheduler_simple_SMP_Insert_ready_lifo(
+static void _Scheduler_simple_SMP_Insert_ready(
   Scheduler_Context *context,
-  Scheduler_Node    *node_to_insert
+  Scheduler_Node    *node_to_insert,
+  Priority_Control   insert_priority
 )
 {
   Scheduler_simple_SMP_Context *self;
-  Priority_Control              priority_to_insert;
 
   self = _Scheduler_simple_SMP_Get_self( context );
-  priority_to_insert = _Scheduler_SMP_Node_priority( node_to_insert );
 
   _Chain_Insert_ordered_unprotected(
     &self->Ready,
     &node_to_insert->Node.Chain,
-    &priority_to_insert,
-    _Scheduler_SMP_Insert_priority_lifo_order
-  );
-}
-
-static void _Scheduler_simple_SMP_Insert_ready_fifo(
-  Scheduler_Context *context,
-  Scheduler_Node    *node_to_insert
-)
-{
-  Scheduler_simple_SMP_Context *self;
-  Priority_Control              priority_to_insert;
-
-  self = _Scheduler_simple_SMP_Get_self( context );
-  priority_to_insert = _Scheduler_SMP_Node_priority( node_to_insert );
-
-  _Chain_Insert_ordered_unprotected(
-    &self->Ready,
-    &node_to_insert->Node.Chain,
-    &priority_to_insert,
-    _Scheduler_SMP_Insert_priority_fifo_order
+    &insert_priority,
+    _Scheduler_SMP_Priority_less_equal
   );
 }
 
@@ -200,103 +181,45 @@ void _Scheduler_simple_SMP_Block(
   );
 }
 
-static bool _Scheduler_simple_SMP_Enqueue_ordered(
-  Scheduler_Context    *context,
-  Scheduler_Node       *node,
-  Chain_Node_order      order,
-  Scheduler_SMP_Insert  insert_ready,
-  Scheduler_SMP_Insert  insert_scheduled
+static bool _Scheduler_simple_SMP_Enqueue(
+  Scheduler_Context *context,
+  Scheduler_Node    *node,
+  Priority_Control   insert_priority
 )
 {
-  return _Scheduler_SMP_Enqueue_ordered(
+  return _Scheduler_SMP_Enqueue(
     context,
     node,
-    order,
-    insert_ready,
-    insert_scheduled,
+    insert_priority,
+    _Scheduler_SMP_Priority_less_equal,
+    _Scheduler_simple_SMP_Insert_ready,
+    _Scheduler_SMP_Insert_scheduled,
     _Scheduler_simple_SMP_Move_from_scheduled_to_ready,
     _Scheduler_SMP_Get_lowest_scheduled,
     _Scheduler_SMP_Allocate_processor_lazy
   );
 }
 
-static bool _Scheduler_simple_SMP_Enqueue_lifo(
-  Scheduler_Context *context,
-  Scheduler_Node    *node
-)
-{
-  return _Scheduler_simple_SMP_Enqueue_ordered(
-    context,
-    node,
-    _Scheduler_SMP_Insert_priority_lifo_order,
-    _Scheduler_simple_SMP_Insert_ready_lifo,
-    _Scheduler_SMP_Insert_scheduled_lifo
-  );
-}
-
-static bool _Scheduler_simple_SMP_Enqueue_fifo(
-  Scheduler_Context *context,
-  Scheduler_Node    *node
-)
-{
-  return _Scheduler_simple_SMP_Enqueue_ordered(
-    context,
-    node,
-    _Scheduler_SMP_Insert_priority_fifo_order,
-    _Scheduler_simple_SMP_Insert_ready_fifo,
-    _Scheduler_SMP_Insert_scheduled_fifo
-  );
-}
-
-static bool _Scheduler_simple_SMP_Enqueue_scheduled_ordered(
+static bool _Scheduler_simple_SMP_Enqueue_scheduled(
   Scheduler_Context *context,
-  Scheduler_Node *node,
-  Chain_Node_order order,
-  Scheduler_SMP_Insert insert_ready,
-  Scheduler_SMP_Insert insert_scheduled
+  Scheduler_Node    *node,
+  Priority_Control   insert_priority
 )
 {
-  return _Scheduler_SMP_Enqueue_scheduled_ordered(
+  return _Scheduler_SMP_Enqueue_scheduled(
     context,
     node,
-    order,
+    insert_priority,
+    _Scheduler_SMP_Priority_less_equal,
     _Scheduler_simple_SMP_Extract_from_ready,
     _Scheduler_simple_SMP_Get_highest_ready,
-    insert_ready,
-    insert_scheduled,
+    _Scheduler_simple_SMP_Insert_ready,
+    _Scheduler_SMP_Insert_scheduled,
     _Scheduler_simple_SMP_Move_from_ready_to_scheduled,
     _Scheduler_SMP_Allocate_processor_lazy
   );
 }
 
-static bool _Scheduler_simple_SMP_Enqueue_scheduled_lifo(
-  Scheduler_Context *context,
-  Scheduler_Node *node
-)
-{
-  return _Scheduler_simple_SMP_Enqueue_scheduled_ordered(
-    context,
-    node,
-    _Scheduler_SMP_Insert_priority_lifo_order,
-    _Scheduler_simple_SMP_Insert_ready_lifo,
-    _Scheduler_SMP_Insert_scheduled_lifo
-  );
-}
-
-static bool _Scheduler_simple_SMP_Enqueue_scheduled_fifo(
-  Scheduler_Context *context,
-  Scheduler_Node *node
-)
-{
-  return _Scheduler_simple_SMP_Enqueue_scheduled_ordered(
-    context,
-    node,
-    _Scheduler_SMP_Insert_priority_fifo_order,
-    _Scheduler_simple_SMP_Insert_ready_fifo,
-    _Scheduler_SMP_Insert_scheduled_fifo
-  );
-}
-
 void _Scheduler_simple_SMP_Unblock(
   const Scheduler_Control *scheduler,
   Thread_Control          *thread,
@@ -310,7 +233,7 @@ void _Scheduler_simple_SMP_Unblock(
     thread,
     node,
     _Scheduler_simple_SMP_Do_update,
-    _Scheduler_simple_SMP_Enqueue_fifo
+    _Scheduler_simple_SMP_Enqueue
   );
 }
 
@@ -324,9 +247,9 @@ static bool _Scheduler_simple_SMP_Do_ask_for_help(
     context,
     the_thread,
     node,
-    _Scheduler_SMP_Insert_priority_lifo_order,
-    _Scheduler_simple_SMP_Insert_ready_lifo,
-    _Scheduler_SMP_Insert_scheduled_lifo,
+    _Scheduler_SMP_Priority_less_equal,
+    _Scheduler_simple_SMP_Insert_ready,
+    _Scheduler_SMP_Insert_scheduled,
     _Scheduler_simple_SMP_Move_from_scheduled_to_ready,
     _Scheduler_SMP_Get_lowest_scheduled,
     _Scheduler_SMP_Allocate_processor_lazy
@@ -347,10 +270,8 @@ void _Scheduler_simple_SMP_Update_priority(
     node,
     _Scheduler_simple_SMP_Extract_from_ready,
     _Scheduler_simple_SMP_Do_update,
-    _Scheduler_simple_SMP_Enqueue_fifo,
-    _Scheduler_simple_SMP_Enqueue_lifo,
-    _Scheduler_simple_SMP_Enqueue_scheduled_fifo,
-    _Scheduler_simple_SMP_Enqueue_scheduled_lifo,
+    _Scheduler_simple_SMP_Enqueue,
+    _Scheduler_simple_SMP_Enqueue_scheduled,
     _Scheduler_simple_SMP_Do_ask_for_help
   );
 }
@@ -414,7 +335,7 @@ void _Scheduler_simple_SMP_Add_processor(
     context,
     idle,
     _Scheduler_simple_SMP_Has_ready,
-    _Scheduler_simple_SMP_Enqueue_scheduled_fifo,
+    _Scheduler_simple_SMP_Enqueue_scheduled,
     _Scheduler_SMP_Do_nothing_register_idle
   );
 }
@@ -430,7 +351,7 @@ Thread_Control *_Scheduler_simple_SMP_Remove_processor(
     context,
     cpu,
     _Scheduler_simple_SMP_Extract_from_ready,
-    _Scheduler_simple_SMP_Enqueue_fifo
+    _Scheduler_simple_SMP_Enqueue
   );
 }
 
@@ -447,7 +368,7 @@ void _Scheduler_simple_SMP_Yield(
     thread,
     node,
     _Scheduler_simple_SMP_Extract_from_ready,
-    _Scheduler_simple_SMP_Enqueue_fifo,
-    _Scheduler_simple_SMP_Enqueue_scheduled_fifo
+    _Scheduler_simple_SMP_Enqueue,
+    _Scheduler_simple_SMP_Enqueue_scheduled
   );
 }
diff --git a/cpukit/score/src/schedulersimpleunblock.c b/cpukit/score/src/schedulersimpleunblock.c
index 5540e20e87..2f5c8636f5 100644
--- a/cpukit/score/src/schedulersimpleunblock.c
+++ b/cpukit/score/src/schedulersimpleunblock.c
@@ -28,13 +28,15 @@ void _Scheduler_simple_Unblock(
 )
 {
   Scheduler_simple_Context *context;
-  Priority_Control          priority;
+  unsigned int              priority;
+  unsigned int              insert_priority;
 
   (void) node;
 
   context = _Scheduler_simple_Get_context( scheduler );
-  _Scheduler_simple_Insert_priority_fifo( &context->Ready, the_thread );
   priority = _Thread_Get_priority( the_thread );
+  insert_priority = SCHEDULER_PRIORITY_APPEND( priority );
+  _Scheduler_simple_Insert( &context->Ready, the_thread, insert_priority );
 
   /*
    *  If the thread that was unblocked is more important than the heir,
diff --git a/cpukit/score/src/schedulersimpleyield.c b/cpukit/score/src/schedulersimpleyield.c
index 0c150d8b1f..95f9cd3540 100644
--- a/cpukit/score/src/schedulersimpleyield.c
+++ b/cpukit/score/src/schedulersimpleyield.c
@@ -26,12 +26,16 @@ void _Scheduler_simple_Yield(
   Scheduler_Node          *node
 )
 {
-  Scheduler_simple_Context *context =
-    _Scheduler_simple_Get_context( scheduler );
+  Scheduler_simple_Context *context;
+  unsigned int              insert_priority;
+
+  context = _Scheduler_simple_Get_context( scheduler );
 
   (void) node;
 
   _Chain_Extract_unprotected( &the_thread->Object.Node );
-  _Scheduler_simple_Insert_priority_fifo( &context->Ready, the_thread );
+  insert_priority = (unsigned int) _Thread_Get_priority( the_thread );
+  insert_priority = SCHEDULER_PRIORITY_APPEND( insert_priority );
+  _Scheduler_simple_Insert( &context->Ready, the_thread, insert_priority );
   _Scheduler_simple_Schedule_body( scheduler, the_thread, false );
 }
diff --git a/cpukit/score/src/schedulerstrongapa.c b/cpukit/score/src/schedulerstrongapa.c
index 57ffb61367..19d4ebe348 100644
--- a/cpukit/score/src/schedulerstrongapa.c
+++ b/cpukit/score/src/schedulerstrongapa.c
@@ -66,7 +66,7 @@ static void _Scheduler_strong_APA_Move_from_ready_to_scheduled(
 {
   Scheduler_strong_APA_Context *self;
   Scheduler_strong_APA_Node    *node;
-  Priority_Control              priority;
+  Priority_Control              insert_priority;
 
   self = _Scheduler_strong_APA_Get_self( context );
   node = _Scheduler_strong_APA_Node_downcast( ready_to_scheduled );
@@ -76,47 +76,41 @@ static void _Scheduler_strong_APA_Move_from_ready_to_scheduled(
     &node->Ready_queue,
     &self->Bit_map
   );
-  priority = node->Base.priority;
+  insert_priority = _Scheduler_SMP_Node_priority( &node->Base.Base );
+  insert_priority = SCHEDULER_PRIORITY_APPEND( insert_priority );
   _Chain_Insert_ordered_unprotected(
     &self->Base.Scheduled,
     &node->Base.Base.Node.Chain,
-    &priority,
-    _Scheduler_SMP_Insert_priority_fifo_order
+    &insert_priority,
+    _Scheduler_SMP_Priority_less_equal
   );
 }
 
-static void _Scheduler_strong_APA_Insert_ready_lifo(
+static void _Scheduler_strong_APA_Insert_ready(
   Scheduler_Context *context,
-  Scheduler_Node    *the_thread
-)
-{
-  Scheduler_strong_APA_Context *self =
-    _Scheduler_strong_APA_Get_self( context );
-  Scheduler_strong_APA_Node *node =
-    _Scheduler_strong_APA_Node_downcast( the_thread );
-
-  _Scheduler_priority_Ready_queue_enqueue(
-    &node->Base.Base.Node.Chain,
-    &node->Ready_queue,
-    &self->Bit_map
-  );
-}
-
-static void _Scheduler_strong_APA_Insert_ready_fifo(
-  Scheduler_Context *context,
-  Scheduler_Node    *the_thread
+  Scheduler_Node    *node_base,
+  Priority_Control   insert_priority
 )
 {
-  Scheduler_strong_APA_Context *self =
-    _Scheduler_strong_APA_Get_self( context );
-  Scheduler_strong_APA_Node *node =
-    _Scheduler_strong_APA_Node_downcast( the_thread );
+  Scheduler_strong_APA_Context *self;
+  Scheduler_strong_APA_Node    *node;
 
-  _Scheduler_priority_Ready_queue_enqueue_first(
-    &node->Base.Base.Node.Chain,
-    &node->Ready_queue,
-    &self->Bit_map
-  );
+  self = _Scheduler_strong_APA_Get_self( context );
+  node = _Scheduler_strong_APA_Node_downcast( node_base );
+
+  if ( SCHEDULER_PRIORITY_IS_APPEND( insert_priority ) ) {
+    _Scheduler_priority_Ready_queue_enqueue(
+      &node->Base.Base.Node.Chain,
+      &node->Ready_queue,
+      &self->Bit_map
+    );
+  } else {
+    _Scheduler_priority_Ready_queue_enqueue_first(
+      &node->Base.Base.Node.Chain,
+      &node->Ready_queue,
+      &self->Bit_map
+    );
+  }
 }
 
 static void _Scheduler_strong_APA_Extract_from_ready(
@@ -150,7 +144,7 @@ static void _Scheduler_strong_APA_Do_update(
   _Scheduler_SMP_Node_update_priority( &node->Base, new_priority );
   _Scheduler_priority_Ready_queue_update(
     &node->Ready_queue,
-    new_priority,
+    SCHEDULER_PRIORITY_UNMAP( new_priority ),
     &self->Bit_map,
     &self->Ready[ 0 ]
   );
@@ -198,7 +192,7 @@ void _Scheduler_strong_APA_Node_initialize(
   self = _Scheduler_strong_APA_Get_self( context );
   _Scheduler_priority_Ready_queue_update(
     &the_node->Ready_queue,
-    priority,
+    SCHEDULER_PRIORITY_UNMAP( priority ),
     &self->Bit_map,
     &self->Ready[ 0 ]
   );
@@ -247,103 +241,45 @@ void _Scheduler_strong_APA_Block(
   );
 }
 
-static bool _Scheduler_strong_APA_Enqueue_ordered(
-  Scheduler_Context    *context,
-  Scheduler_Node       *node,
-  Chain_Node_order      order,
-  Scheduler_SMP_Insert  insert_ready,
-  Scheduler_SMP_Insert  insert_scheduled
+static bool _Scheduler_strong_APA_Enqueue(
+  Scheduler_Context *context,
+  Scheduler_Node    *node,
+  Priority_Control   insert_priority
 )
 {
-  return _Scheduler_SMP_Enqueue_ordered(
+  return _Scheduler_SMP_Enqueue(
     context,
     node,
-    order,
-    insert_ready,
-    insert_scheduled,
+    insert_priority,
+    _Scheduler_SMP_Priority_less_equal,
+    _Scheduler_strong_APA_Insert_ready,
+    _Scheduler_SMP_Insert_scheduled,
     _Scheduler_strong_APA_Move_from_scheduled_to_ready,
     _Scheduler_SMP_Get_lowest_scheduled,
     _Scheduler_SMP_Allocate_processor_exact
   );
 }
 
-static bool _Scheduler_strong_APA_Enqueue_lifo(
-  Scheduler_Context *context,
-  Scheduler_Node    *node
-)
-{
-  return _Scheduler_strong_APA_Enqueue_ordered(
-    context,
-    node,
-    _Scheduler_SMP_Insert_priority_lifo_order,
-    _Scheduler_strong_APA_Insert_ready_lifo,
-    _Scheduler_SMP_Insert_scheduled_lifo
-  );
-}
-
-static bool _Scheduler_strong_APA_Enqueue_fifo(
+static bool _Scheduler_strong_APA_Enqueue_scheduled(
   Scheduler_Context *context,
-  Scheduler_Node    *node
-)
-{
-  return _Scheduler_strong_APA_Enqueue_ordered(
-    context,
-    node,
-    _Scheduler_SMP_Insert_priority_fifo_order,
-    _Scheduler_strong_APA_Insert_ready_fifo,
-    _Scheduler_SMP_Insert_scheduled_fifo
-  );
-}
-
-static bool _Scheduler_strong_APA_Enqueue_scheduled_ordered(
-  Scheduler_Context    *context,
-  Scheduler_Node       *node,
-  Chain_Node_order      order,
-  Scheduler_SMP_Insert  insert_ready,
-  Scheduler_SMP_Insert  insert_scheduled
+  Scheduler_Node    *node,
+  Priority_Control  insert_priority
 )
 {
-  return _Scheduler_SMP_Enqueue_scheduled_ordered(
+  return _Scheduler_SMP_Enqueue_scheduled(
     context,
     node,
-    order,
+    insert_priority,
+    _Scheduler_SMP_Priority_less_equal,
     _Scheduler_strong_APA_Extract_from_ready,
     _Scheduler_strong_APA_Get_highest_ready,
-    insert_ready,
-    insert_scheduled,
+    _Scheduler_strong_APA_Insert_ready,
+    _Scheduler_SMP_Insert_scheduled,
     _Scheduler_strong_APA_Move_from_ready_to_scheduled,
     _Scheduler_SMP_Allocate_processor_exact
   );
 }
 
-static bool _Scheduler_strong_APA_Enqueue_scheduled_lifo(
-  Scheduler_Context *context,
-  Scheduler_Node    *node
-)
-{
-  return _Scheduler_strong_APA_Enqueue_scheduled_ordered(
-    context,
-    node,
-    _Scheduler_SMP_Insert_priority_lifo_order,
-    _Scheduler_strong_APA_Insert_ready_lifo,
-    _Scheduler_SMP_Insert_scheduled_lifo
-  );
-}
-
-static bool _Scheduler_strong_APA_Enqueue_scheduled_fifo(
-  Scheduler_Context *context,
-  Scheduler_Node    *node
-)
-{
-  return _Scheduler_strong_APA_Enqueue_scheduled_ordered(
-    context,
-    node,
-    _Scheduler_SMP_Insert_priority_fifo_order,
-    _Scheduler_strong_APA_Insert_ready_fifo,
-    _Scheduler_SMP_Insert_scheduled_fifo
-  );
-}
-
 void _Scheduler_strong_APA_Unblock(
   const Scheduler_Control *scheduler,
   Thread_Control          *the_thread,
@@ -357,7 +293,7 @@ void _Scheduler_strong_APA_Unblock(
     the_thread,
     node,
     _Scheduler_strong_APA_Do_update,
-    _Scheduler_strong_APA_Enqueue_fifo
+    _Scheduler_strong_APA_Enqueue
   );
 }
 
@@ -371,9 +307,9 @@ static bool _Scheduler_strong_APA_Do_ask_for_help(
     context,
     the_thread,
     node,
-    _Scheduler_SMP_Insert_priority_lifo_order,
-    _Scheduler_strong_APA_Insert_ready_lifo,
-    _Scheduler_SMP_Insert_scheduled_lifo,
+    _Scheduler_SMP_Priority_less_equal,
+    _Scheduler_strong_APA_Insert_ready,
+    _Scheduler_SMP_Insert_scheduled,
     _Scheduler_strong_APA_Move_from_scheduled_to_ready,
     _Scheduler_SMP_Get_lowest_scheduled,
     _Scheduler_SMP_Allocate_processor_lazy
@@ -394,10 +330,8 @@ void _Scheduler_strong_APA_Update_priority(
     node,
     _Scheduler_strong_APA_Extract_from_ready,
     _Scheduler_strong_APA_Do_update,
-    _Scheduler_strong_APA_Enqueue_fifo,
-    _Scheduler_strong_APA_Enqueue_lifo,
-    _Scheduler_strong_APA_Enqueue_scheduled_fifo,
-    _Scheduler_strong_APA_Enqueue_scheduled_lifo,
+    _Scheduler_strong_APA_Enqueue,
+    _Scheduler_strong_APA_Enqueue_scheduled,
     _Scheduler_strong_APA_Do_ask_for_help
   );
 }
@@ -461,7 +395,7 @@ void _Scheduler_strong_APA_Add_processor(
     context,
     idle,
     _Scheduler_strong_APA_Has_ready,
-    _Scheduler_strong_APA_Enqueue_scheduled_fifo,
+    _Scheduler_strong_APA_Enqueue_scheduled,
     _Scheduler_SMP_Do_nothing_register_idle
   );
 }
@@ -477,7 +411,7 @@ Thread_Control *_Scheduler_strong_APA_Remove_processor(
     context,
     cpu,
     _Scheduler_strong_APA_Extract_from_ready,
-    _Scheduler_strong_APA_Enqueue_fifo
+    _Scheduler_strong_APA_Enqueue
   );
 }
 
@@ -494,7 +428,7 @@ void _Scheduler_strong_APA_Yield(
     the_thread,
     node,
     _Scheduler_strong_APA_Extract_from_ready,
-    _Scheduler_strong_APA_Enqueue_fifo,
-    _Scheduler_strong_APA_Enqueue_scheduled_fifo
+    _Scheduler_strong_APA_Enqueue,
+    _Scheduler_strong_APA_Enqueue_scheduled
   );
 }
diff --git a/testsuites/smptests/smpscheduler01/smpscheduler01.doc b/testsuites/smptests/smpscheduler01/smpscheduler01.doc
index def7dac128..a881fc0fc4 100644
--- a/testsuites/smptests/smpscheduler01/smpscheduler01.doc
+++ b/testsuites/smptests/smpscheduler01/smpscheduler01.doc
@@ -4,7 +4,7 @@ test set name: smpscheduler01
 
 directives:
 
-  - _Scheduler_SMP_Enqueue_ordered()
+  - _Scheduler_SMP_Enqueue()
   - _Scheduler_SMP_Block()
 
 concepts:
diff --git a/testsuites/sptests/spintrcritical23/init.c b/testsuites/sptests/spintrcritical23/init.c
index c0a159471c..02c8a7ef37 100644
--- a/testsuites/sptests/spintrcritical23/init.c
+++ b/testsuites/sptests/spintrcritical23/init.c
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2015, 2016 embedded brains GmbH.  All rights reserved.
+ * Copyright (c) 2015, 2017 embedded brains GmbH.  All rights reserved.
  *
  *  embedded brains GmbH
  *  Dornierstr. 4
@@ -43,12 +43,15 @@ static void change_priority(rtems_id timer, void *arg)
   /* The arg is NULL */
   test_context *ctx = &ctx_instance;
   rtems_interrupt_lock_context lock_context;
+  unsigned int next_priority;
 
   rtems_interrupt_lock_acquire(&ctx->lock, &lock_context);
-  if (
-    ctx->scheduler_node->Ready_queue.current_priority
-      != ctx->scheduler_node->Base.Priority.value
-  ) {
+
+  next_priority = SCHEDULER_PRIORITY_UNMAP(
+    (unsigned int) ctx->scheduler_node->Base.Priority.value
+  );
+
+  if ( ctx->scheduler_node->Ready_queue.current_priority != next_priority ) {
     rtems_task_priority priority_interrupt;
     rtems_task_priority priority_task;
     rtems_task_priority previous;
@@ -84,11 +87,13 @@ static bool test_body(void *arg)
   rtems_task_priority previous;
 
   rtems_interrupt_lock_acquire(&ctx->lock, &lock_context);
+
   priority_last = ctx->priority_task;
   priority_task = 1 + (priority_last + 1) % 3;
   priority_interrupt = 1 + (priority_task + 1) % 3;
   ctx->priority_task = priority_task;
   ctx->priority_interrupt = priority_interrupt;
+
   rtems_interrupt_lock_release(&ctx->lock, &lock_context);
 
   sc = rtems_task_set_priority(