there is a bug that can occur when an op is scheduled before predecessors

b_asic/scheduler.py

@@ -181,7 +181,7 @@ class EarliestDeadlineScheduler(Scheduler):
             Schedule to apply the scheduling algorithm on.
         """
 
-        # TODO: Take the execution time into consideration!
+        # TODO: Solve bug where operation (ADD) is scheduled before proceeding (MUL) -> pipelining
 
         ALAPScheduler().apply_scheduling(schedule)
 
@@ -190,9 +190,15 @@ class EarliestDeadlineScheduler(Scheduler):
             input_op = cast(Input, input_op)
             schedule.move_operation_asap(input_op.graph_id)
 
+        # construct the set of remaining operations, excluding inputs
         remaining_ops = set(schedule.start_times.keys())
         remaining_ops = {elem for elem in remaining_ops if not elem.startswith("in")}
 
+        # construct a dictionarry for storing how many times until a resource is available again
+        used_resources_ready_times = {}
+
+        # iterate through all remaining operations and schedule them
+        # while not exceeding the available resources
         remaining_resources = self._max_resources.copy()
         current_time = 0
         while remaining_ops:
@@ -202,13 +208,23 @@ class EarliestDeadlineScheduler(Scheduler):
 
             if not best_candidate:
                 current_time += 1
-                remaining_resources = self._max_resources.copy()
+
+                # update available operators
+                for operation, ready_time in used_resources_ready_times.items():
+                    print(ready_time, current_time)
+                    if ready_time == current_time:
+                        remaining_resources[operation.type_name()] += 1
+                # remaining_resources = self._max_resources.copy()
                 continue
 
-            # update remaining resources
+            # if the resource is constrained, update remaining resources
             if best_candidate.type_name() in remaining_resources:
                 remaining_resources[best_candidate.type_name()] -= 1
+                used_resources_ready_times[best_candidate] = (
+                    current_time + best_candidate.execution_time
+                )
 
+            # schedule the best candidate to the current time
             remaining_ops.remove(best_candidate.graph_id)
             schedule.start_times[best_candidate.graph_id] = current_time
 
@@ -222,11 +238,16 @@ class EarliestDeadlineScheduler(Scheduler):
     def _find_best_candidate(
         schedule, remaining_ops, remaining_resources, current_time
     ):
-        # precompute source end times for faster checks
         sfg = schedule.sfg
         source_end_times = defaultdict(float)
+
+        # find the best candidate
+        best_candidate = None
+        best_deadline = float('inf')
         for op_id in remaining_ops:
             operation = sfg.find_by_id(op_id)
+
+            # compute maximum end times of preceding operations
             for op_input in operation.inputs:
                 source_op = op_input.signals[0].source.operation
                 if not isinstance(source_op, Delay):
@@ -235,11 +256,6 @@ class EarliestDeadlineScheduler(Scheduler):
                         schedule.start_times[source_op.graph_id] + source_op.latency,
                     )
 
-        best_candidate = None
-        best_deadline = float('inf')
-        for op_id in remaining_ops:
-            operation = sfg.find_by_id(op_id)
-
             # check resource constraints
             if operation.type_name() in remaining_resources:
                 if remaining_resources[operation.type_name()] == 0: