ACE/Kokyu/DSRT_Dispatcher_Impl_T.h

   1 /* -*- C++ -*- */
   2 /**
   3  *  @file   DSRT_Dispatcher_Impl_T.h
   4  */
   5
   6 #ifndef DSRT_DISPATCHER_IMPL_H
   7 #define DSRT_DISPATCHER_IMPL_H
   8 #include /**/ "ace/pre.h"
   9
  10 #include "ace/Synch_Traits.h"
  11 #if defined (ACE_HAS_THREADS)
  12 #  include "ace/Recursive_Thread_Mutex.h"
  13 #else
  14 #  include "ace/Null_Mutex.h"
  15 #endif /* ACE_HAS_THREADS */
  16
  17 #include "Kokyu_dsrt.h"
  18
  19 #if !defined (ACE_LACKS_PRAGMA_ONCE)
  20 # pragma once
  21 #endif /* ACE_LACKS_PRAGMA_ONCE */
  22
  23
  24 namespace Kokyu
  25 {
  26   /**
  27    * @class Comparator_Adapter_Generator
  28    *
  29    * @brief Generates function object adapter that adapts the
  30    * QoSComparator function object to compare between two schedulable
  31    * items instead of QoSDescriptors.
  32    *
  33    * The QoSComparator function object that gets passed through the
  34    * <code> DSRT_Scheduler_Traits </code> takes two qos values and
  35    * determines the more eligible one. Since the INT_ID (key) for
  36    * RB_Tree needs to be of type <code> DSRT_Dispatch_Item_var
  37    * </code>, the QoSComparator needs to be adapted using an adapter
  38    * to compare two schedulable items. This adapter compares the two
  39    * using their qos values. Ties are resolved by giving preference to
  40    * items which arrived earlier. Note that this class serves the
  41    * purpose of a generator class, since it generates the adapter
  42    * class for a given qos comparator function object.
  43    */
  44
  45   template <class DSRT_Scheduler_Traits>
  46   class Comparator_Adapter_Generator
  47   {
  48   public:
  49     typedef typename
  50     DSRT_Scheduler_Traits::QoSComparator_t QoSComparator_t;
  51
  52     /**
  53      * @class More_Eligible
  54      *
  55      * @brief Actual function object that gets generated.
  56      */
  57     class MoreEligible
  58     {
  59     public:
  60       /**
  61        * Function call operator to do comparison between two
  62        * schedulable items. Returns 1 if item1 is more eligible than
  63        * item2, otherwise 0.
  64        */
  65       int operator ()
  66         (const DSRT_Dispatch_Item_var<DSRT_Scheduler_Traits>& item1,
  67          const DSRT_Dispatch_Item_var<DSRT_Scheduler_Traits>& item2)
  68       {
  69         int rc = qos_comparator_ (item1->qos (), item2->qos ());
  70
  71 #ifdef KOKYU_DSRT_LOGGING
  72         ACE_DEBUG ((LM_DEBUG,
  73                     "(%t|%T): MoreEligible:: qos_comparator returned %d\n",
  74                     rc));
  75 #endif
  76
  77         //more eligible
  78         if (rc == 1)
  79           return rc;
  80
  81         //if equally eligible, then resolve tie with the creation time of
  82         //the item
  83         if (rc == 0 && item1->insertion_time () < item2->insertion_time ())
  84           return 1;
  85
  86         return 0;
  87       }
  88
  89     private:
  90       QoSComparator_t qos_comparator_;
  91     };
  92
  93     /**
  94      * Facilitates return of the generated function object adapter.
  95      */
  96     typedef MoreEligible RET_FUNC;
  97   };
  98
  99   /**
 100    * @class DSRT_Dispatcher
 101    *
 102    * @brief Base class for DSRT dispatcher implementations
 103    *
 104    * The responsibility of this class is to act as a common base class
 105    * for different DSRT dispatcher implementations. This is an
 106    * abstract base class and cannot be instantiated.
 107    */
 108   template <class DSRT_Scheduler_Traits>
 109   class DSRT_Dispatcher_Impl
 110   {
 111   public:
 112     typedef typename DSRT_Scheduler_Traits::Guid_t Guid_t;
 113     typedef typename DSRT_Scheduler_Traits::QoSDescriptor_t DSRT_QoSDescriptor;
 114
 115     DSRT_Dispatcher_Impl (ACE_Sched_Params::Policy sched_policy,
 116                           int sched_scope);
 117
 118     /// Configure the DSRT dispatcher.
 119     int init (const DSRT_ConfigInfo&);
 120
 121     /// Schedule a thread dynamically based on the qos info supplied.
 122     int schedule (Guid_t guid,
 123                   const DSRT_QoSDescriptor&);
 124
 125     /// Update the schedule for a thread. This could alter the current
 126     /// schedule.
 127     int update_schedule (Guid_t guid,
 128                          const DSRT_QoSDescriptor&);
 129
 130     /// Inform the scheduler that the caller thread is about to
 131     /// block. This could alter the current schedule.
 132     int update_schedule (Guid_t guid, Block_Flag_t flag);
 133
 134     /// Cancel the schedule for a thread. This could alter the current
 135     /// schedule.
 136     int cancel_schedule (Guid_t guid);
 137
 138     /// Shut down the dispatcher. The dispatcher will stop processing
 139     /// requests.
 140     int shutdown ();
 141
 142     virtual ~DSRT_Dispatcher_Impl ();
 143
 144   private:
 145     //following an idiom to avoid public virtual functions.
 146     //instead make them private and use the template method
 147     //pattern - "Virtually Yours" article in CUJ Experts Forum
 148
 149     virtual int init_i (const DSRT_ConfigInfo&)=0;
 150     virtual int schedule_i (Guid_t guid,
 151                     const DSRT_QoSDescriptor&)=0;
 152     virtual int update_schedule_i (Guid_t guid,
 153                            const DSRT_QoSDescriptor&)=0;
 154     virtual int update_schedule_i (Guid_t guid, Block_Flag_t flag)=0;
 155     virtual int cancel_schedule_i (Guid_t guid)=0;
 156     virtual int shutdown_i ()=0;
 157
 158   protected:
 159     /// Generate the QoSComparator adapter.
 160     typedef typename
 161     Comparator_Adapter_Generator<DSRT_Scheduler_Traits>::RET_FUNC
 162     Queue_Item_Comparator_t;
 163
 164     typedef Sched_Ready_Queue<DSRT_Scheduler_Traits,
 165                               Queue_Item_Comparator_t,
 166                               ACE_SYNCH_NULL_MUTEX>
 167     DSRT_Sched_Queue_t;
 168
 169     ACE_Sched_Params::Policy sched_policy_;
 170     int sched_scope_;
 171
 172     Priority_t min_prio_;
 173     Priority_t max_prio_;
 174     Priority_t executive_prio_;
 175     Priority_t blocked_prio_;
 176     Priority_t inactive_prio_;
 177     Priority_t active_prio_;
 178
 179     DSRT_Sched_Queue_t ready_queue_;
 180     int shutdown_flagged_;
 181     long non_rt_thr_flags_;
 182     long rt_thr_flags_;
 183
 184     ACE_SYNCH_RECURSIVE_MUTEX synch_lock_;
 185
 186     ACE_hthread_t curr_scheduled_thr_handle_;
 187     Guid_t curr_scheduled_guid_;
 188   };
 189 } //end of namespace
 190
 191 #if defined (__ACE_INLINE__)
 192 #include "DSRT_Dispatcher_Impl_T.inl"
 193 #endif /* __ACE_INLINE__ */
 194
 195 #include "DSRT_Dispatcher_Impl_T.cpp"
 196
 197 #include /**/ "ace/post.h"
 198 #endif /* DSRT_DISPATCHER_IMPL_H */