improve state cache performance

backend-python/utils/rwkv.py

@@ -239,14 +239,9 @@ class AbstractRWKV(ABC):
             self.model_tokens = []
         else:
             delta_prompt = prompt[len(cache["prompt"]) :]
-            state = cache["state"]
-            self.model_state = (
-                copy.deepcopy(state)
-                if type(state) == list or type(state) == np.ndarray
-                else state
-            )
-            self.model_tokens = copy.deepcopy(cache["tokens"])
-            logits = copy.deepcopy(cache["logits"])
+            self.model_state = cache["state"]
+            self.model_tokens = cache["tokens"]
+            logits = cache["logits"]
 
         prompt_token_len = 0
         if delta_prompt != "":