score: Introduce CPU budget operations

This patch set replaces the CPU budget algorithm enumeration with a set of CPU
budget operations which implement a particular CPU budget algorithm.  This
helps to hide the CPU budget algorithm implementation details from the general
thread handling.  The CPU budget callouts are turned into CPU budget
operations.  This slightly reduces the size of the thread control block.

All schedulers used the default scheduler tick implementation.  The tick
scheduler operation is removed and the CPU budget operations are directly used
in _Watchdog_Tick() if the executing thread uses a CPU budget algorithm.  This
is performance improvement for all threads which do not use a CPU budget
algorithm (default behaviour).

1 files changed, 2 insertions, 12 deletions

diff --git a/cpukit/include/rtems/score/threadimpl.h b/cpukit/include/rtems/score/threadimpl.h
index a983975568..b1ec05f1c4 100644
--- a/cpukit/include/rtems/score/threadimpl.h
+++ b/cpukit/include/rtems/score/threadimpl.h
@@ -176,19 +176,9 @@ typedef struct {
   Priority_Control priority;
 
   /**
-   * @brief The thread's budget algorithm.
+   * @brief The thread's initial CPU budget operations.
    */
-  Thread_CPU_budget_algorithms budget_algorithm;
-
-  /**
-   * @brief The thread's initial budget callout.
-   */
-  Thread_CPU_budget_algorithm_callout budget_callout;
-
-  /**
-   * @brief The thread's initial CPU time budget.
-   */
-  uint32_t cpu_time_budget;
+  const Thread_CPU_budget_operations *cpu_budget_operations;
 
   /**
    * @brief 32-bit unsigned integer name of the object for the thread.