Files
vllm/tests/config/test_mp_reducer.py
2025-10-05 07:06:22 -07:00

57 lines
1.9 KiB
Python

# SPDX-License-Identifier: Apache-2.0
# SPDX-FileCopyrightText: Copyright contributors to the vLLM project
import sys
from unittest.mock import patch
from vllm.config import VllmConfig
from vllm.engine.arg_utils import AsyncEngineArgs
from vllm.v1.engine.async_llm import AsyncLLM
def test_mp_reducer(monkeypatch):
"""
Test that _reduce_config reducer is registered when AsyncLLM is instantiated
without transformers_modules. This is a regression test for
https://github.com/vllm-project/vllm/pull/18640.
"""
# Use V1 AsyncLLM which calls maybe_register_config_serialize_by_value
monkeypatch.setenv("VLLM_USE_V1", "1")
# Ensure transformers_modules is not in sys.modules
if "transformers_modules" in sys.modules:
del sys.modules["transformers_modules"]
with patch("multiprocessing.reducer.register") as mock_register:
engine_args = AsyncEngineArgs(
model="facebook/opt-125m",
max_model_len=32,
gpu_memory_utilization=0.1,
disable_log_stats=True,
)
async_llm = AsyncLLM.from_engine_args(
engine_args,
start_engine_loop=False,
)
assert mock_register.called, (
"multiprocessing.reducer.register should have been called"
)
vllm_config_registered = False
for call_args in mock_register.call_args_list:
# Verify that a reducer for VllmConfig was registered
if len(call_args[0]) >= 2 and call_args[0][0] == VllmConfig:
vllm_config_registered = True
reducer_func = call_args[0][1]
assert callable(reducer_func), "Reducer function should be callable"
break
assert vllm_config_registered, (
"VllmConfig should have been registered to multiprocessing.reducer"
)
async_llm.shutdown()