[Frontend] Avoid list copies in `serving_chat.py` (#22947)

Signed-off-by: Nick Hill <nhill@redhat.com>

vllm/entrypoints/openai/serving_chat.py

@@ -50,6 +50,7 @@ from vllm.transformers_utils.tokenizer import AnyTokenizer, MistralTokenizer
 from vllm.transformers_utils.tokenizers import (maybe_serialize_tool_calls,
                                                 truncate_tool_call_ids,
                                                 validate_request_params)
+from vllm.utils import as_list
 
 logger = init_logger(__name__)
 
@@ -670,10 +671,10 @@ class OpenAIServingChat(OpenAIServing):
 
                         # avoid the None + list error.
                         if previous_token_ids:
-                            current_token_ids = previous_token_ids + list(
+                            current_token_ids = previous_token_ids + as_list(
                                 output.token_ids)
                         else:
-                            current_token_ids = list(output.token_ids)
+                            current_token_ids = as_list(output.token_ids)
 
                     if self.use_harmony:
                         if is_final:
@@ -703,11 +704,10 @@ class OpenAIServingChat(OpenAIServing):
                             # set reasoning status to end.
                             # Only keep 'content', remove 'reasoning_content'.
                             if reasoning_parser.is_reasoning_end(
-                                    list(output.token_ids)) or \
-                                    (res.prompt_token_ids and
-                                        reasoning_parser.is_reasoning_end(
-                                            list(res.prompt_token_ids)
-                                        )):
+                                    as_list(output.token_ids)) or (
+                                        res.prompt_token_ids
+                                        and reasoning_parser.is_reasoning_end(
+                                            res.prompt_token_ids)):
                                 reasoning_end_arr[i] = True
                                 if delta_message and delta_message.content:
                                     # This need to be added to next `delta_text`
@@ -771,6 +771,7 @@ class OpenAIServingChat(OpenAIServing):
                         assert reasoning_parser is not None
                         assert added_content_delta_arr is not None
                         assert reasoning_end_arr is not None
+                        output_token_ids = as_list(output.token_ids)
                         if not reasoning_end_arr[i]:
                             delta_message = (
                                 reasoning_parser.
@@ -780,7 +781,7 @@ class OpenAIServingChat(OpenAIServing):
                                     delta_text,
                                     previous_token_ids,
                                     current_token_ids,
-                                    output.token_ids,
+                                    output_token_ids,
                                 ))
                             # When encountering think end id in prompt_token_ids
                             # i.e {"enable_thinking": False},
@@ -789,9 +790,9 @@ class OpenAIServingChat(OpenAIServing):
                             # to 'reasoning_content'.
                             if res.prompt_token_ids and \
                                 reasoning_parser.is_reasoning_end(
-                                    list(res.prompt_token_ids)):
+                                    res.prompt_token_ids):
                                 reasoning_end_arr[i] = True
-                                current_token_ids = list(output.token_ids)
+                                current_token_ids = output_token_ids
                                 if delta_message and delta_message.content:
                                     current_text = delta_message.content
                                     delta_message.content = None
@@ -802,11 +803,11 @@ class OpenAIServingChat(OpenAIServing):
                             # Remove the text and token ids related
                             # to 'reasoning_content'.
                             if reasoning_parser.is_reasoning_end(
-                                    list(output.token_ids)):
+                                    output_token_ids):
                                 reasoning_end_arr[i] = True
                                 current_token_ids =  \
                                     reasoning_parser.extract_content_ids(
-                                        list(output.token_ids))
+                                        output_token_ids)
                                 if delta_message and delta_message.content:
                                     current_text = delta_message.content
                                     delta_message.content = None
@@ -815,7 +816,7 @@ class OpenAIServingChat(OpenAIServing):
 
                         # handle tool calls only after reasoning is done,
                         else:
-                            delta_token_ids = list(output.token_ids)
+                            delta_token_ids = output_token_ids
                             # First time to tool call,
                             # add the remaining text and token ids
                             # to delta from previous
@@ -899,7 +900,7 @@ class OpenAIServingChat(OpenAIServing):
                             self.request_logger.log_outputs(
                                 request_id=request_id,
                                 outputs=delta_content,
-                                output_token_ids=list(output.token_ids),
+                                output_token_ids=as_list(output.token_ids),
                                 finish_reason=output.finish_reason,
                                 is_streaming=True,
                                 delta=True,

vllm/reasoning/abs_reasoning_parsers.py

@@ -44,7 +44,7 @@ class ReasoningParser:
         return self.model_tokenizer.get_vocab()
 
     @abstractmethod
-    def is_reasoning_end(self, input_ids: Sequence[int]) -> bool:
+    def is_reasoning_end(self, input_ids: list[int]) -> bool:
         """
         Check if the reasoning content ends in the input_ids.