diff --git a/tests/common/vllm_test.py b/tests/common/vllm_test.py
index f05e50498e..0f0ef93e76 100644
--- a/tests/common/vllm_test.py
+++ b/tests/common/vllm_test.py
@@ -1,7 +1,6 @@
 import os
 import unittest
 
-import ray
 import torch
 from transformers import AutoTokenizer
 
@@ -131,12 +130,12 @@ def test_generate(self):
 
 class TestModelWrapperSyncV0(BaseTestModelWrapper, RayUnittestBase):
     def setUp(self):
-        ray.init(ignore_reinit_error=True)
         self.config = get_template_config()
         self.config.model.model_path = get_model_path()
         self.config.explorer.engine_type = "vllm"
         self.config.explorer.tensor_parallel_size = 1
         self.config.explorer.engine_num = 2
+        self.config.explorer.repeat_times = 2
         self.config.explorer.chat_template = CHAT_TEMPLATE
         self.engines = create_rollout_models(self.config)
         self.model_wrapper = ModelWrapper(self.engines[0], model_type="vllm")
@@ -144,12 +143,12 @@ def setUp(self):
 
 class TestModelWrapperAsyncV0(BaseTestModelWrapper, RayUnittestBase):
     def setUp(self):
-        ray.init(ignore_reinit_error=True)
         self.config = get_template_config()
         self.config.model.model_path = get_model_path()
         self.config.explorer.engine_type = "vllm_async"
         self.config.explorer.engine_num = 2
         self.config.explorer.tensor_parallel_size = 1
+        self.config.explorer.repeat_times = 2
         self.config.explorer.use_v1 = False
         self.config.explorer.chat_template = CHAT_TEMPLATE
         self.engines = create_rollout_models(self.config)
@@ -158,7 +157,6 @@ def setUp(self):
 
 class TestModelWrapperAsyncTPV0(BaseTestModelWrapper, RayUnittestBase):
     def setUp(self):
-        ray.init(ignore_reinit_error=True)
         self.config = get_template_config()
         self.config.model.model_path = get_model_path()
         self.config.explorer.engine_type = "vllm_async"
@@ -172,12 +170,12 @@ def setUp(self):
 
 class TestModelWrapperAsyncTPV1(BaseTestModelWrapper, RayUnittestBase):
     def setUp(self):
-        ray.init(ignore_reinit_error=True)
         self.config = get_template_config()
         self.config.model.model_path = get_model_path()
         self.config.explorer.engine_type = "vllm_async"
         self.config.explorer.engine_num = 2
         self.config.explorer.tensor_parallel_size = 2
+        self.config.explorer.repeat_times = 2
         self.config.explorer.use_v1 = True
         self.config.explorer.chat_template = CHAT_TEMPLATE
         self.engines = create_rollout_models(self.config)
@@ -186,7 +184,6 @@ def setUp(self):
 
 class TestModelWrapperAsyncV1(BaseTestModelWrapper, RayUnittestBase):
     def setUp(self):
-        ray.init(ignore_reinit_error=True)
         self.config = get_template_config()
         self.config.model.model_path = get_model_path()
         self.config.explorer.engine_type = "vllm_async"
diff --git a/trinity/common/models/vllm_async_model.py b/trinity/common/models/vllm_async_model.py
index 4134161ef5..50a774d8d4 100644
--- a/trinity/common/models/vllm_async_model.py
+++ b/trinity/common/models/vllm_async_model.py
@@ -12,6 +12,7 @@
 import ray
 import torch
 import vllm
+from vllm.sampling_params import RequestOutputKind
 
 from trinity.common.config import Config
 from trinity.common.experience import Experience
@@ -61,6 +62,7 @@ def __init__(
             truncate_prompt_tokens=config.model.max_prompt_tokens,
             skip_special_tokens=True,
             include_stop_str_in_output=False,
+            output_kind=RequestOutputKind.FINAL_ONLY,
             logprobs=config.explorer.logprobs,
         )
         self.request_id = 0
@@ -148,10 +150,8 @@ async def generate_async(self, prompt: str, **kwargs) -> List[Experience]:
         Returns:
             A list of experiences.
         """
-        request_id = self.request_id
-        self.request_id += 1
         async with self.semaphore:
-            output = await self._generate_internal(request_id=request_id, prompt=prompt, **kwargs)
+            output = await self._generate_internal(prompt=prompt, **kwargs)
         experiences = [
             Experience(
                 tokens=torch.cat(
@@ -186,11 +186,8 @@ async def generate_async(self, prompt: str, **kwargs) -> List[Experience]:
 
     async def logprobs_async(self, token_ids: List[int]) -> torch.Tensor:
         """Calculate the logprobs of the given tokens in async."""
-        request_id = self.request_id
-        self.request_id += 1
         async with self.semaphore:
             output = await self._generate_internal(
-                request_id=request_id,
                 prompt={"prompt_token_ids": token_ids},
                 n=1,
                 max_tokens=1,
@@ -205,10 +202,11 @@ async def logprobs_async(self, token_ids: List[int]) -> torch.Tensor:
             dtype=torch.float32,
         )
 
-    async def _generate_internal(self, request_id: int, prompt: Any, **kwargs) -> Any:
+    async def _generate_internal(self, prompt: Any, **kwargs) -> Any:
         # Send the request to the LLM engine.
+        self.request_id += 1
         stream = self.async_llm.generate(
-            request_id=str(request_id),
+            request_id=str(self.request_id),
             prompt=prompt,
             sampling_params=self._create_sampling_params(**kwargs),
         )