Fix prompt len in parallel sampling (#928)

python/sglang/srt/openai_api/adapter.py

@@ -500,7 +500,9 @@ def v1_generate_response(request, ret, tokenizer_manager, to_file=False):
             responses.append(response)
         return responses
     else:
-        prompt_tokens = sum(item["meta_info"]["prompt_tokens"] for item in ret)
+        prompt_tokens = sum(
+            ret[i]["meta_info"]["prompt_tokens"] for i in range(0, len(ret), request.n)
+        )
         completion_tokens = sum(item["meta_info"]["completion_tokens"] for item in ret)
         response = CompletionResponse(
             id=ret[0]["meta_info"]["id"],
@@ -707,8 +709,6 @@ def v1_chat_generate_request(all_requests, tokenizer_manager):
 
 def v1_chat_generate_response(request, ret, to_file=False):
     choices = []
-    total_prompt_tokens = 0
-    total_completion_tokens = 0
 
     for idx, ret_item in enumerate(ret):
         logprobs = False
@@ -747,8 +747,6 @@ def v1_chat_generate_response(request, ret, to_file=False):
             choice_logprobs = ChoiceLogprobs(content=token_logprobs)
         else:
             choice_logprobs = None
-        prompt_tokens = ret_item["meta_info"]["prompt_tokens"]
-        completion_tokens = ret_item["meta_info"]["completion_tokens"]
 
         if to_file:
             # to make the choice data json serializable
@@ -767,8 +765,7 @@ def v1_chat_generate_response(request, ret, to_file=False):
             )
 
         choices.append(choice_data)
-        total_prompt_tokens += prompt_tokens
-        total_completion_tokens += completion_tokens
+
     if to_file:
         responses = []
 
@@ -795,14 +792,18 @@ def v1_chat_generate_response(request, ret, to_file=False):
             responses.append(response)
         return responses
     else:
+        prompt_tokens = sum(
+            ret[i]["meta_info"]["prompt_tokens"] for i in range(0, len(ret), request.n)
+        )
+        completion_tokens = sum(item["meta_info"]["completion_tokens"] for item in ret)
         response = ChatCompletionResponse(
             id=ret[0]["meta_info"]["id"],
             model=request.model,
             choices=choices,
             usage=UsageInfo(
-                prompt_tokens=total_prompt_tokens,
-                completion_tokens=total_completion_tokens,
-                total_tokens=total_prompt_tokens + total_completion_tokens,
+                prompt_tokens=prompt_tokens,
+                completion_tokens=completion_tokens,
+                total_tokens=prompt_tokens + completion_tokens,
             ),
         )
         return response

test/srt/test_openai_server.py

@@ -45,11 +45,6 @@ def run_completion(
             prompt_arg = prompt_input
             num_choices = 1
 
-        if parallel_sample_num:
-            # FIXME: This is wrong. We should not count the prompt tokens multiple times for
-            # parallel sampling.
-            num_prompt_tokens *= parallel_sample_num
-
         response = client.completions.create(
             model=self.model,
             prompt=prompt_arg,