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

1 files changed, 55 insertions, 121 deletions

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
   );
 }