Fix get_max_num_running_seqs for waiting and swapped seq groups (#1068)

vllm/sequence.py

@@ -250,8 +250,8 @@ class SequenceGroup:
                 # generation stage, we will have `best_of` sequences running.
                 return self.sampling_params.best_of
             # At sampling stages, return the number of actual sequences
-            # running.
-            return self.num_seqs(status=SequenceStatus.RUNNING)
+            # that are not finished yet.
+            return self.num_unfinished_seqs()
 
     def get_seqs(
         self,
@@ -264,12 +264,23 @@ class SequenceGroup:
                 seq for seq in self.seqs_dict.values() if seq.status == status
             ]
 
+    def get_unfinished_seqs(self) -> List[Sequence]:
+        return [
+            seq for seq in self.seqs_dict.values() if not seq.is_finished()
+        ]
+
     def get_finished_seqs(self) -> List[Sequence]:
         return [seq for seq in self.seqs_dict.values() if seq.is_finished()]
 
     def num_seqs(self, status: Optional[SequenceStatus] = None) -> int:
         return len(self.get_seqs(status))
 
+    def num_unfinished_seqs(self) -> int:
+        return len(self.get_unfinished_seqs())
+
+    def num_finished_seqs(self) -> int:
+        return len(self.get_finished_seqs())
+
     def find(self, seq_id: int) -> Sequence:
         if seq_id not in self.seqs_dict:
             raise ValueError(f"Sequence {seq_id} not found.")