- Bits and tits of step_forward

git-svn-id: svn://svn.gna.org/svn/sgpemv2/trunk@785 3ecf2c5c-341e-0410-92b4-d18e462d057c

src/backend/scheduler.cc

@@ -39,6 +39,12 @@ using namespace sgpem;
 template class SG_DLLEXPORT Singleton<Scheduler>;
 
 
+typedef std::vector<DynamicProcess*>    Processes;
+typedef std::vector<DynamicRequest*>    Requests;
+typedef std::vector<DynamicSubRequest*> SubRequests;
+typedef std::vector<DynamicThread*>     Threads;
+
+
 // ------------------ Static helper functions --------------
 
 
@@ -73,6 +79,50 @@ static void prepare_ready_queue(ConcreteEnvironment&         snapshot,
 }
 
 
+// For the current thread, see if there are requests that are exhausted
+static void
+update_requests_for_old_running_thread(DynamicThread& running_thread)
+{
+	Requests& reqs = running_thread.get_dynamic_requests();
+	bool running_terminated = running_thread.get_state() == Schedulable::state_terminated;
+	
+	for(Requests::iterator r_it = reqs.begin(); r_it != reqs.end(); r_it++)
+		{
+			DynamicRequest& rq = **r_it;
+			
+			// If the running thread terminated uncoditionally put them in exhausted state
+			if(running_terminated)
+				{
+					SubRequests& subreqs = rq.get_dynamic_subrequests();
+					for(SubRequests::iterator s_it = subreqs.begin(); s_it != subreqs.end(); s_it++)
+						(*s_it)->set_state(Request::state_exhausted);
+					continue; // go to next request
+				}
+			
+			if(rq.get_state() == Request::state_allocated)
+				{
+					/* decrease remaining time for each allocated subrequest */
+					SubRequests& subreqs = rq.get_dynamic_subrequests();
+					for(SubRequests::iterator s_it = subreqs.begin(); s_it != subreqs.end(); s_it++)
+						{
+							DynamicSubRequest& subr = **s_it;
+							if(subr.get_state() == Request::state_allocated)
+								subr.decrease_remaining_time();
+							if(subr.get_remaining_time() == 0)
+								{
+									subr.set_state(Request::state_exhausted);
+									
+									// ___BIG___ FIXME FIXME FIXME
+
+
+									// FIXME : if exhausted, it should be taken away from the queue of the 
+									// requested resource
+
+								}
+						}
+				} 
+		} //~ for(over requests)
+}
 
 // ---------------------------------------------------------
 
@@ -125,17 +175,13 @@ Scheduler::step_forward(History& history, Policy& cpu_policy) throw(UserInterrup
 	// FIXME: handle me! I'm not just a pretty boolean, I want to be *USED*! *EXPLOITED*!
 	//        *RAPED*! *MAKE ME BLEED*!
 	bool simulation_ended = true; // Assume we've finished. Then prove me wrong.
+	unsigned int current_instant = history.get_size(); /* They should be equivalent */
 
 	ConcreteHistory& concrete_history = (ConcreteHistory&) history;
  
 	// Use an auto_ptr since we've some exceptions in the coming...
 	auto_ptr<ConcreteEnvironment> new_snapshot(new ConcreteEnvironment(concrete_history.get_last_environment()));
  
-	typedef std::vector<DynamicProcess*>    Processes;
-	typedef std::vector<DynamicRequest*>    Requests;
-	typedef std::vector<DynamicSubRequest*> SubRequests;
-	typedef std::vector<DynamicThread*>     Threads;
- 
 	Threads all_threads;
 	DynamicThread* running_thread = NULL;
 
@@ -182,56 +228,7 @@ Scheduler::step_forward(History& history, Policy& cpu_policy) throw(UserInterrup
  
 	// 4a. Look for exhausted requests for the running thread
 	if(running_thread != NULL) 
-		{
+		update_requests_for_old_running_thread(*running_thread);			
-			Requests& reqs = running_thread->get_dynamic_requests();
-			bool running_terminated = running_thread->get_state() == Schedulable::state_terminated;
-			
-			for(Requests::iterator r_it = reqs.begin(); r_it != reqs.end(); r_it++)
-				{
-					DynamicRequest& rq = **r_it;
-
-					// If the running thread terminated uncoditionally put them in exhausted state
-					if(running_terminated)
-						{
-							SubRequests& subreqs = rq.get_dynamic_subrequests();
-							for(SubRequests::iterator s_it = subreqs.begin(); s_it != subreqs.end(); s_it++)
-								(*s_it)->set_state(Request::state_exhausted);
-							continue; // go to next request
-						}
-					
-					if(rq.get_state() == Request::state_allocated)
-						{
-							/* decrease remaining time for each allocated subrequest */
-							SubRequests& subreqs = rq.get_dynamic_subrequests();
-							for(SubRequests::iterator s_it = subreqs.begin(); s_it != subreqs.end(); s_it++)
-								{
-									DynamicSubRequest& subr = **s_it;
-									if(subr.get_state() == Request::state_allocated)
-										subr.decrease_remaining_time();
-									if(subr.get_remaining_time() == 0)
-										{
-											subr.set_state(Request::state_exhausted);
-											
-											// FIXME : if exhausted, it should be taken away from the queue of the 
-											// requested resource
-										}
-								}
-						} 
-				} //~ for(over requests)
-			
-			// FIXME we lack a way to tell and/or remember for how 
-			// much a subrequest has been being fulfilled
-			// THIS MEANS this part is NOT complete
-			// We should check if a request has been fulfilled
-			
-			// FIXME If a request was being fulfilled to the running thread,
-			// we should decrease the request remaining time here.
-			
-			// This is why we kept a ref to the old running thread,
-			// even if it was terminated
-			
-			
-		} //~ if running_thread != NULL
 	
 	
 	// ----------  FIXME ----------------
@@ -250,7 +247,8 @@ Scheduler::step_forward(History& history, Policy& cpu_policy) throw(UserInterrup
 	 */
 
  
-	prepare_ready_queue(*new_snapshot, all_threads);
+	bool preemptible_policy;
+	unsigned int  time_slice;
 	try
 		{
 			// Temporarily set the _ready_queue param and the _policy one for 
@@ -260,8 +258,62 @@ Scheduler::step_forward(History& history, Policy& cpu_policy) throw(UserInterrup
 			
 			// ?. Use the policy to sort the queue
 
-			// FIXME: how does it get the queue?
+			preemptible_policy = cpu_policy.is_pre_emptive();
-			cpu_policy.sort_queue();
+			time_slice = cpu_policy.get_time_slice();
+			
+			// ?. See if old running_thread has to be put to ready state
+			// This happens when the policy makes use of preemptability by
+			// priority, or when a time slice ended
+			if(running_thread != NULL && running_thread->get_state() == Schedulable::state_running &&
+				   (preemptible_policy ||
+						time_slice == current_instant - running_thread->get_last_acquisition()) )
+				{
+					running_thread->set_state(Schedulable::state_ready);
+					running_thread->set_last_release(current_instant);
+				}
+
+
+			// ?. Ask the policy to sort the queue. We do this multiple time if we must select
+			// a new thread and it can't run for some reason (goes blocked, or terminates).
+			bool selected_cant_run;
+			do
+				{
+					selected_cant_run = false;
+					prepare_ready_queue(*new_snapshot, all_threads);
+					
+					if(_ready_queue->size() == 0) 
+						break; // No sense in trying to schedule something that isn't there
+					
+					cpu_policy.sort_queue();
+					
+					DynamicThread& candidate = (DynamicThread&) _ready_queue->get_item_at(0);
+					
+					// We could have threads with 0 duration. Silly, but possible.
+					if(candidate.get_total_cpu_time() - candidate.get_elapsed_time() == 0)
+						{
+							candidate.set_last_acquisition(current_instant);
+							candidate.set_last_release(current_instant);
+							candidate.set_state(Schedulable::state_terminated);
+							// FIXME : check requests for thread at instant 0?
+							selected_cant_run = true;
+							continue;
+						}
+
+					// FIXME : check if the first thread of the queue blocks
+					
+				}
+			while(selected_cant_run);
+
+			// ?. Finally select the new thread (if appropriate); now we're sure it can run
+			if(_ready_queue->size() > 0 && (running_thread == NULL || running_thread->get_state() != Schedulable::state_running))
+				{
+					// Fix fields of running thread
+					DynamicThread& new_running = (DynamicThread&) _ready_queue->get_item_at(0);
+					new_running.set_state(Schedulable::state_running);
+					new_running.set_last_acquisition(current_instant);
+				}
+					
+
 		}
 	catch(UserInterruptException& e)
 		{
@@ -275,7 +327,7 @@ Scheduler::step_forward(History& history, Policy& cpu_policy) throw(UserInterrup
 			//    - the user that the policy sucks
 			//    - SimulationController that everything stopped
 			throw;
-		}
+		}		
  
 	// append the new snapshot...
 	// ...and remember to release the auto_ptr!