[Bug]: AsyncLLMEngine stuck in V1
Your current environment
INFO 06-20 10:55:55 [init.py:244] Automatically detected platform cuda. Collecting environment information...
System Info
============================== OS : Ubuntu 22.04.5 LTS (x86_64) GCC version : (Ubuntu 11.4.0-1ubuntu1~22.04) 11.4.0 Clang version : Could not collect CMake version : version 4.0.2 Libc version : glibc-2.35
============================== PyTorch Info
PyTorch version : 2.7.0+cu126 Is debug build : False CUDA used to build PyTorch : 12.6 ROCM used to build PyTorch : N/A
============================== Python Environment
Python version : 3.12.10 | packaged by conda-forge | (main, Apr 10 2025, 22:21:13) [GCC 13.3.0] (64-bit runtime) Python platform : Linux-5.10.134-16.1.al8.x86_64-x86_64-with-glibc2.35
============================== CUDA / GPU Info
Is CUDA available : True CUDA runtime version : Could not collect CUDA_MODULE_LOADING set to : LAZY GPU models and configuration : GPU 0: NVIDIA H20 Nvidia driver version : 550.54.15 cuDNN version : Could not collect HIP runtime version : N/A MIOpen runtime version : N/A Is XNNPACK available : True
============================== CPU Info
架构: x86_64 CPU 运行模式: 32-bit, 64-bit Address sizes: 52 bits physical, 57 bits virtual 字节序: Little Endian CPU: 24 在线 CPU 列表: 0-23 厂商 ID: GenuineIntel 型号名称: Intel(R) Xeon(R) Platinum 8469C CPU 系列: 6 型号: 143 每个核的线程数: 2 每个座的核数: 12 座: 1 步进: 8 CPU 最大 MHz: 3800.0000 CPU 最小 MHz: 800.0000 BogoMIPS: 5200.00 标记: fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat pse36 clflush mmx fxsr sse sse2 ss ht syscall nx pdpe1gb rdtscp lm constant_tsc rep_good nopl xtopology nonstop_tsc cpuid aperfmperf tsc_known_freq pni pclmulqdq monitor ssse3 fma cx16 pdcm pcid sse4_1 sse4_2 x2apic movbe popcnt aes xsave avx f16c rdrand hypervisor lahf_lm abm 3dnowprefetch cpuid_fault invpcid_single ibrs_enhanced fsgsbase tsc_adjust bmi1 hle avx2 smep bmi2 erms invpcid rtm avx512f avx512dq rdseed adx smap avx512ifma clflushopt clwb avx512cd sha_ni avx512bw avx512vl xsaveopt xsavec xgetbv1 xsaves avx_vnni avx512_bf16 wbnoinvd ida arat hwp hwp_notify hwp_act_window hwp_epp hwp_pkg_req avx512vbmi umip pku ospke waitpkg avx512_vbmi2 gfni vaes vpclmulqdq avx512_vnni avx512_bitalg avx512_vpopcntdq rdpid bus_lock_detect cldemote movdiri movdir64b enqcmd fsrm uintr md_clear serialize tsxldtrk amx_bf16 avx512_fp16 amx_tile amx_int8 arch_capabilities 超管理器厂商: KVM 虚拟化类型: 完全 L1d 缓存: 576 KiB (12 instances) L1i 缓存: 384 KiB (12 instances) L2 缓存: 24 MiB (12 instances) L3 缓存: 97.5 MiB (1 instance) NUMA 节点: 1 NUMA 节点0 CPU: 0-23 Vulnerability Itlb multihit: Not affected Vulnerability L1tf: Not affected Vulnerability Mds: Not affected Vulnerability Meltdown: Not affected Vulnerability Mmio stale data: Not affected Vulnerability Retbleed: Not affected Vulnerability Spec store bypass: Vulnerable Vulnerability Spectre v1: Mitigation; usercopy/swapgs barriers and __user pointer sanitization Vulnerability Spectre v2: Mitigation; Enhanced IBRS, RSB filling, PBRSB-eIBRS SW sequence Vulnerability Srbds: Not affected Vulnerability Tsx async abort: Not affected
============================== Versions of relevant libraries
[pip3] numpy==1.26.4 [pip3] nvidia-cublas-cu12==12.6.4.1 [pip3] nvidia-cuda-cupti-cu12==12.6.80 [pip3] nvidia-cuda-nvrtc-cu12==12.6.77 [pip3] nvidia-cuda-runtime-cu12==12.6.77 [pip3] nvidia-cudnn-cu12==9.5.1.17 [pip3] nvidia-cufft-cu12==11.3.0.4 [pip3] nvidia-cufile-cu12==1.11.1.6 [pip3] nvidia-curand-cu12==10.3.7.77 [pip3] nvidia-cusolver-cu12==11.7.1.2 [pip3] nvidia-cusparse-cu12==12.5.4.2 [pip3] nvidia-cusparselt-cu12==0.6.3 [pip3] nvidia-ml-py==12.575.51 [pip3] nvidia-nccl-cu12==2.26.2 [pip3] nvidia-nvjitlink-cu12==12.6.85 [pip3] nvidia-nvtx-cu12==12.6.77 [pip3] pytorch-lightning==2.5.1.post0 [pip3] pyzmq==26.2.0 [pip3] torch==2.7.0 [pip3] torchaudio==2.7.0 [pip3] torchmetrics==0.10.3 [pip3] torchvision==0.22.0 [pip3] transformers==4.52.4 [pip3] triton==3.3.0 [conda] numpy 1.26.4 pypi_0 pypi [conda] nvidia-cublas-cu12 12.6.4.1 pypi_0 pypi [conda] nvidia-cuda-cupti-cu12 12.6.80 pypi_0 pypi [conda] nvidia-cuda-nvrtc-cu12 12.6.77 pypi_0 pypi [conda] nvidia-cuda-runtime-cu12 12.6.77 pypi_0 pypi [conda] nvidia-cudnn-cu12 9.5.1.17 pypi_0 pypi [conda] nvidia-cufft-cu12 11.3.0.4 pypi_0 pypi [conda] nvidia-cufile-cu12 1.11.1.6 pypi_0 pypi [conda] nvidia-curand-cu12 10.3.7.77 pypi_0 pypi [conda] nvidia-cusolver-cu12 11.7.1.2 pypi_0 pypi [conda] nvidia-cusparse-cu12 12.5.4.2 pypi_0 pypi [conda] nvidia-cusparselt-cu12 0.6.3 pypi_0 pypi [conda] nvidia-ml-py 12.575.51 pypi_0 pypi [conda] nvidia-nccl-cu12 2.26.2 pypi_0 pypi [conda] nvidia-nvjitlink-cu12 12.6.85 pypi_0 pypi [conda] nvidia-nvtx-cu12 12.6.77 pypi_0 pypi [conda] pytorch-lightning 2.5.1.post0 pypi_0 pypi [conda] pyzmq 26.4.0 pypi_0 pypi [conda] torch 2.7.0 pypi_0 pypi [conda] torchaudio 2.7.0 pypi_0 pypi [conda] torchmetrics 0.10.3 pypi_0 pypi [conda] torchvision 0.22.0 pypi_0 pypi [conda] transformers 4.52.4 pypi_0 pypi [conda] triton 3.3.0 pypi_0 pypi
============================== vLLM Info
ROCM Version : Could not collect Neuron SDK Version : N/A vLLM Version : 0.9.1 vLLM Build Flags: CUDA Archs: Not Set; ROCm: Disabled; Neuron: Disabled GPU Topology: GPU0 CPU Affinity NUMA Affinity GPU NUMA ID GPU0 X 0-23 0 N/A
Legend:
X = Self SYS = Connection traversing PCIe as well as the SMP interconnect between NUMA nodes (e.g., QPI/UPI) NODE = Connection traversing PCIe as well as the interconnect between PCIe Host Bridges within a NUMA node PHB = Connection traversing PCIe as well as a PCIe Host Bridge (typically the CPU) PXB = Connection traversing multiple PCIe bridges (without traversing the PCIe Host Bridge) PIX = Connection traversing at most a single PCIe bridge NV# = Connection traversing a bonded set of # NVLinks
============================== Environment Variables
NCCL_CUMEM_ENABLE=0 PYTORCH_NVML_BASED_CUDA_CHECK=1 TORCHINDUCTOR_COMPILE_THREADS=1 CUDA_MODULE_LOADING=LAZY
🐛 Describe the bug
AsyncLLMEngine stucks in V1, but works in V0.
predict.py
from vllm import SamplingParams
from vllm.lora.request import LoRARequest
import time
# from loguru import logger
import torch
async def async_gen(model, text, uid):
results_generator = model.generate(
text,
SamplingParams(
n=1, # Number of output sequences to return for each prompt.
top_k=1, # Float that controls the cumulative probability of the top tokens to consider.
temperature=0, # randomness of the sampling
seed=777, # Seed for reprodicibility
skip_special_tokens=False, # Whether to skip special tokens in the output.
max_tokens=1, # Maximum number of tokens to generate per output sequence.
],
logprobs=25
),
uid,
lora_request=LoRARequest("clue_type", 1, "./checkpoint-300")
)
final_output = None
async for request_output in results_generator:
final_output = request_output
return final_output
async def predict_clue_type(model, tokenizer, inputs, uid):
text = inputs["text"]
responses = await async_gen(model, text, uid)
return {"success": True, "prob": prob, "message": ""}
main.py
@app.post("/v1/models/{model_name}:predict")
async def predict(request: Item): # async def predict(request: Item):
inputs = request.dict()
st = time.time()
md5 = hashlib.md5()
md5.update(json.dumps(inputs, indent=4, ensure_ascii=False).encode("utf-8"))
uid = md5.hexdigest()
random_uid = uuid.uuid4()
try:
res = await predict_clue_type(engine, tokenizer, inputs, random_uid)
except:
error_mess = json.dumps(
{ "uid": uid,
"input": inputs,
"error": traceback.format_exc()
}, indent = 4)
#logger.error(error_mess)
print(error_mess)
res = {"success": False, "message": error_mess, "prob": -1}
finally:
et = time.time()
cost_time = round(et - st, 1)
#logger.info(f"Predict {uid} costs : {cost_time}s")
print(f"Predict {uid} costs : {cost_time}s")
return res
@app.on_event("startup")
async def startup_event():
st = time.time()
global tokenizer, engine
tokenizer = AutoTokenizer.from_pretrained('./Qwen3-8B')
engine = AsyncLLMEngine.from_engine_args(
AsyncEngineArgs(
model="./Qwen3-8B",
tensor_parallel_size=1,
gpu_memory_utilization=0.5,
trust_remote_code=True,
dtype="bfloat16" if is_bfloat16_supported() else "float16",
enforce_eager=True,
max_model_len=4096,
disable_log_stats=True,
max_logprobs=25,
enable_lora=True,
max_lora_rank=64,
disable_log_requests=True
)
)
et = time.time()
cost_time = round(et - st, 1)
print(f"Initalization costs : {cost_time}s")
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