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, 9 insertions, 43 deletions

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
   );
 }