add policy manager

aphrodite/processing/block_manager.py

@@ -1,5 +1,5 @@
 """A block manager that manages token blocks."""
-from typing import Dict, List, Optional, Set, Tuple, Any
+from typing import Dict, List, Optional, Set, Tuple
 from aphrodite.block import PhysicalTokenBlock
 from aphrodite.sequence import Sequence, SequenceGroup, SequenceStatus
 from aphrodite.utils import Device

aphrodite/processing/policy.py

@@ -0,0 +1,42 @@
+from typing import List
+
+from aphrodite.sequence import SequenceGroup
+
+class Policy:
+
+    def get_priority(
+        self,
+        now: float,
+        seq_group: SequenceGroup,
+    ) -> float:
+        raise NotImplementedError
+
+    def sort_by_priority(
+        self,
+        now: float,
+        seq_groups: List[SequenceGroup],
+    ) -> List[SequenceGroup]:
+        return sorted(
+            seq_groups,
+            key=lambda seq_group: self.get_priority(now, seq_group),
+            reverse=True,
+        )
+
+class FCFS(Policy):
+
+    def get_priority(
+        self,
+        now: float,
+        seq_group: SequenceGroup,
+    ) -> float:
+        return now - seq_group.arrival_time
+
+class PolicyFactory:
+
+    _POLICY_REGISTRY = {
+        'fcfs': FCFS,
+    }
+
+    @classmethod
+    def get_policy(cls, policy_name: str, **kwargs) -> Policy:
+        return cls._POLICY_REGISTRY[policy_name](**kwargs)