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A high-throughput and memory-efficient inference and serving engine for LLMs
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[Bug]: vLLM server crashes when `echo=True` and `max_tokens=0` #6521

Open gabrielhuang opened 4 months ago

gabrielhuang commented 4 months ago

Your current environment

vLLM server latest, as of July 17th 2024: vllm/vllm-openai:latest

🐛 Describe the bug

I'm trying to get the logprobability of the last token (Yes or No) of the prompt.

In my client, I set:

import requests

generation_args = {
    "prompt": "Your answer: Yes",
    "temperature": self.temperature,
    "top_p": self.top_p if self.do_sample else 1.0,
    "top_k": self.top_k if self.do_sample else -1,
    "best_of": self.best_of,
    "repetition_penalty": self.repetition_penalty if self.do_sample else 1.0,
    "max_tokens": 0, # no additional tokens to generate (using 1 to not crash vllm server?)
    "n": 1,
    "model": self.model_alias,
    "echo": True,    # include prompt in response, must be true for getting prompt logprobs, see https://github.com/vllm-project/vllm/blob/5f0b9933e63839e816b9736a65a3c55005df2cfe/vllm/entrypoints/openai/protocol.py#L634
    "logprobs": 1
}

url = f"{self.base_url}/v1/completions"
r = requests.post(url, json=generation_args

However, as soon as i query the vLLM server, it crashes with the following message inthe logs

Traceback (most recent call last):
  File "/usr/local/lib/python3.10/dist-packages/vllm/engine/async_llm_engine.py", line 44, in _log_task_completion
    return_value = task.result()
  File "/usr/local/lib/python3.10/dist-packages/vllm/engine/async_llm_engine.py", line 610, in run_engine_loop
INFO 07-17 21:39:42 async_llm_engine.py:169] Aborted request cmpl-7e558e6ae69b4b389dfc33990c172649-0.
    result = task.result()
  File "/usr/local/lib/python3.10/dist-packages/vllm/engine/async_llm_engine.py", line 553, in engine_step
    request_outputs = await self.engine.step_async(virtual_engine)
  File "/usr/local/lib/python3.10/dist-packages/vllm/engine/async_llm_engine.py", line 242, in step_async
    output = await self.model_executor.execute_model_async(
  File "/usr/local/lib/python3.10/dist-packages/vllm/executor/distributed_gpu_executor.py", line 173, in execute_model_async
    return await self._driver_execute_model_async(execute_model_req)
  File "/usr/local/lib/python3.10/dist-packages/vllm/executor/multiproc_gpu_executor.py", line 165, in _driver_execute_model_async
    return await self.driver_exec_model(execute_model_req)
  File "/usr/lib/python3.10/concurrent/futures/thread.py", line 58, in run
INFO:     10.210.207.136:51370 - "POST /v1/completions HTTP/1.1" 500 Internal Server Error
    result = self.fn(*self.args, **self.kwargs)
  File "/usr/local/lib/python3.10/dist-packages/vllm/worker/worker_base.py", line 271, in execute_model
    output = self.model_runner.execute_model(
  File "/usr/local/lib/python3.10/dist-packages/torch/utils/_contextlib.py", line 115, in decorate_context
    return func(*args, **kwargs)
  File "/usr/local/lib/python3.10/dist-packages/vllm/worker/model_runner.py", line 1361, in execute_model
    output: SamplerOutput = self.model.sample(
  File "/usr/local/lib/python3.10/dist-packages/vllm/model_executor/models/llama.py", line 407, in sample
    next_tokens = self.sampler(logits, sampling_metadata)
  File "/usr/local/lib/python3.10/dist-packages/torch/nn/modules/module.py", line 1532, in _wrapped_call_impl
    return self._call_impl(*args, **kwargs)
  File "/usr/local/lib/python3.10/dist-packages/torch/nn/modules/module.py", line 1541, in _call_impl
    return forward_call(*args, **kwargs)
  File "/usr/local/lib/python3.10/dist-packages/vllm/model_executor/layers/sampler.py", line 112, in forward
    prompt_logprobs, sample_logprobs = _get_logprobs(
  File "/usr/local/lib/python3.10/dist-packages/vllm/model_executor/layers/sampler.py", line 763, in _get_logprobs
    assert len(next_token_ids) == len(query_indices)
AssertionError
The above exception was the direct cause of the following exception:
Traceback (most recent call last):
  File "uvloop/cbhandles.pyx", line 63, in uvloop.loop.Handle._run
  File "/usr/local/lib/python3.10/dist-packages/vllm/engine/async_llm_engine.py", line 56, in _log_task_completion
    raise AsyncEngineDeadError(
vllm.engine.async_llm_engine.AsyncEngineDeadError: Task finished unexpectedly. This should never happen! Please open an issue on Github. See stack trace above for theactual cause.
ERROR:    Exception in ASGI application
Traceback (most recent call last):
  File "/usr/local/lib/python3.10/dist-packages/uvicorn/protocols/http/httptools_impl.py", line 399, in run_asgi
    result = await app(  # type: ignore[func-returns-value]
  File "/usr/local/lib/python3.10/dist-packages/uvicorn/middleware/proxy_headers.py", line 70, in __call__
    return await self.app(scope, receive, send)
  File "/usr/local/lib/python3.10/dist-packages/fastapi/applications.py", line 1054, in __call__
    await super().__call__(scope, receive, send)
  File "/usr/local/lib/python3.10/dist-packages/starlette/applications.py", line 123, in __call__
    await self.middleware_stack(scope, receive, send)
  File "/usr/local/lib/python3.10/dist-packages/starlette/middleware/errors.py", line 186, in __call__
    raise exc
  File "/usr/local/lib/python3.10/dist-packages/starlette/middleware/errors.py", line 164, in __call__
    await self.app(scope, receive, _send)
  File "/usr/local/lib/python3.10/dist-packages/starlette/middleware/cors.py", line 85, in __call__
    await self.app(scope, receive, send)
  File "/usr/local/lib/python3.10/dist-packages/starlette/middleware/exceptions.py", line 65, in __call__
    await wrap_app_handling_exceptions(self.app, conn)(scope, receive, send)
  File "/usr/local/lib/python3.10/dist-packages/starlette/_exception_handler.py", line 64, in wrapped_app
    raise exc
  File "/usr/local/lib/python3.10/dist-packages/starlette/_exception_handler.py", line 53, in wrapped_app
    await app(scope, receive, sender)
  File "/usr/local/lib/python3.10/dist-packages/starlette/routing.py", line 756, in __call__
    await self.middleware_stack(scope, receive, send)
  File "/usr/local/lib/python3.10/dist-packages/starlette/routing.py", line 776, in app
    await route.handle(scope, receive, send)
  File "/usr/local/lib/python3.10/dist-packages/starlette/routing.py", line 297, in handle
    await self.app(scope, receive, send)
  File "/usr/local/lib/python3.10/dist-packages/starlette/routing.py", line 77, in app
    await wrap_app_handling_exceptions(app, request)(scope, receive, send)
  File "/usr/local/lib/python3.10/dist-packages/starlette/_exception_handler.py", line 64, in wrapped_app
    raise exc
  File "/usr/local/lib/python3.10/dist-packages/starlette/_exception_handler.py", line 53, in wrapped_app
    await app(scope, receive, sender)
  File "/usr/local/lib/python3.10/dist-packages/starlette/routing.py", line 72, in app
    response = await func(request)
  File "/usr/local/lib/python3.10/dist-packages/fastapi/routing.py", line 278, in app
    raw_response = await run_endpoint_function(
  File "/usr/local/lib/python3.10/dist-packages/fastapi/routing.py", line 191, in run_endpoint_function
    return await dependant.call(**values)
  File "/usr/local/lib/python3.10/dist-packages/vllm/entrypoints/openai/api_server.py", line 139, in create_completion
    generator = await openai_serving_completion.create_completion(
  File "/usr/local/lib/python3.10/dist-packages/vllm/entrypoints/openai/serving_completion.py", line 190, in create_completion
    async for i, res in result_generator:
  File "/usr/local/lib/python3.10/dist-packages/vllm/utils.py", line 319, in consumer
    raise e
  File "/usr/local/lib/python3.10/dist-packages/vllm/utils.py", line 310, in consumer
    raise item
  File "/usr/local/lib/python3.10/dist-packages/vllm/utils.py", line 294, in producer
    async for item in iterator:
  File "/usr/local/lib/python3.10/dist-packages/vllm/engine/async_llm_engine.py", line 765, in generate
    async for output in self._process_request(
  File "/usr/local/lib/python3.10/dist-packages/vllm/engine/async_llm_engine.py", line 881, in _process_request
    raise e
  File "/usr/local/lib/python3.10/dist-packages/vllm/engine/async_llm_engine.py", line 877, in _process_request
    async for request_output in stream:
  File "/usr/local/lib/python3.10/dist-packages/vllm/engine/async_llm_engine.py", line 91, in __anext__
    raise result
  File "/usr/local/lib/python3.10/dist-packages/vllm/engine/async_llm_engine.py", line 44, in _log_task_completion
    return_value = task.result()
  File "/usr/local/lib/python3.10/dist-packages/vllm/engine/async_llm_engine.py", line 610, in run_engine_loop
    result = task.result()
  File "/usr/local/lib/python3.10/dist-packages/vllm/engine/async_llm_engine.py", line 553, in engine_step
    request_outputs = await self.engine.step_async(virtual_engine)
  File "/usr/local/lib/python3.10/dist-packages/vllm/engine/async_llm_engine.py", line 242, in step_async
    output = await self.model_executor.execute_model_async(
  File "/usr/local/lib/python3.10/dist-packages/vllm/executor/distributed_gpu_executor.py", line 173, in execute_model_async
    return await self._driver_execute_model_async(execute_model_req)
  File "/usr/local/lib/python3.10/dist-packages/vllm/executor/multiproc_gpu_executor.py", line 165, in _driver_execute_model_async
    return await self.driver_exec_model(execute_model_req)
  File "/usr/lib/python3.10/concurrent/futures/thread.py", line 58, in run
    result = self.fn(*self.args, **self.kwargs)
  File "/usr/local/lib/python3.10/dist-packages/vllm/worker/worker_base.py", line 271, in execute_model
    output = self.model_runner.execute_model(
  File "/usr/local/lib/python3.10/dist-packages/torch/utils/_contextlib.py", line 115, in decorate_context
    return func(*args, **kwargs)
  File "/usr/local/lib/python3.10/dist-packages/vllm/worker/model_runner.py", line 1361, in execute_model
    output: SamplerOutput = self.model.sample(
  File "/usr/local/lib/python3.10/dist-packages/vllm/model_executor/models/llama.py", line 407, in sample
    next_tokens = self.sampler(logits, sampling_metadata)
  File "/usr/local/lib/python3.10/dist-packages/torch/nn/modules/module.py", line 1532, in _wrapped_call_impl
    return self._call_impl(*args, **kwargs)
  File "/usr/local/lib/python3.10/dist-packages/torch/nn/modules/module.py", line 1541, in _call_impl
    return forward_call(*args, **kwargs)
  File "/usr/local/lib/python3.10/dist-packages/vllm/model_executor/layers/sampler.py", line 112, in forward
    prompt_logprobs, sample_logprobs = _get_logprobs(
  File "/usr/local/lib/python3.10/dist-packages/vllm/model_executor/layers/sampler.py", line 763, in _get_logprobs
    assert len(next_token_ids) == len(query_indices)
AssertionError
INFO 07-17 21:39:48 metrics.py:295] Avg prompt throughput: 0.0 tokens/s, Avg generation throughput: 0.0 tokens/s, Running: 1 reqs, Swapped: 0 reqs, Pending: 0 reqs, GPU KV cache usage: 8.0%, CPU KV cache usage: 0.0%.
INFO:     10.210.208.13:43112 - "GET /health HTTP/1.1" 500 Internal Server Error
ERROR:    Exception in ASGI application
Traceback (most recent call last):
  File "/usr/local/lib/python3.10/dist-packages/uvicorn/protocols/http/httptools_impl.py", line 399, in run_asgi
    result = await app(  # type: ignore[func-returns-value]
  File "/usr/local/lib/python3.10/dist-packages/uvicorn/middleware/proxy_headers.py", line 70, in __call__
    return await self.app(scope, receive, send)
  File "/usr/local/lib/python3.10/dist-packages/fastapi/applications.py", line 1054, in __call__
    await super().__call__(scope, receive, send)
  File "/usr/local/lib/python3.10/dist-packages/starlette/applications.py", line 123, in __call__
    await self.middleware_stack(scope, receive, send)
  File "/usr/local/lib/python3.10/dist-packages/starlette/middleware/errors.py", line 186, in __call__
    raise exc
  File "/usr/local/lib/python3.10/dist-packages/starlette/middleware/errors.py", line 164, in __call__
    await self.app(scope, receive, _send)
  File "/usr/local/lib/python3.10/dist-packages/starlette/middleware/cors.py", line 85, in __call__
    await self.app(scope, receive, send)
  File "/usr/local/lib/python3.10/dist-packages/starlette/middleware/exceptions.py", line 65, in __call__
    await wrap_app_handling_exceptions(self.app, conn)(scope, receive, send)
  File "/usr/local/lib/python3.10/dist-packages/starlette/_exception_handler.py", line 64, in wrapped_app
    raise exc
  File "/usr/local/lib/python3.10/dist-packages/starlette/_exception_handler.py", line 53, in wrapped_app
    await app(scope, receive, sender)
  File "/usr/local/lib/python3.10/dist-packages/starlette/routing.py", line 756, in __call__
    await self.middleware_stack(scope, receive, send)
  File "/usr/local/lib/python3.10/dist-packages/starlette/routing.py", line 776, in app
    await route.handle(scope, receive, send)
  File "/usr/local/lib/python3.10/dist-packages/starlette/routing.py", line 297, in handle
    await self.app(scope, receive, send)
  File "/usr/local/lib/python3.10/dist-packages/starlette/routing.py", line 77, in app
    await wrap_app_handling_exceptions(app, request)(scope, receive, send)
  File "/usr/local/lib/python3.10/dist-packages/starlette/_exception_handler.py", line 64, in wrapped_app
    raise exc
  File "/usr/local/lib/python3.10/dist-packages/starlette/_exception_handler.py", line 53, in wrapped_app
    await app(scope, receive, sender)
  File "/usr/local/lib/python3.10/dist-packages/starlette/routing.py", line 72, in app
    response = await func(request)
  File "/usr/local/lib/python3.10/dist-packages/fastapi/routing.py", line 278, in app
    raw_response = await run_endpoint_function(
  File "/usr/local/lib/python3.10/dist-packages/fastapi/routing.py", line 191, in run_endpoint_function
    return await dependant.call(**values)
  File "/usr/local/lib/python3.10/dist-packages/vllm/entrypoints/openai/api_server.py", line 83, in health
    await openai_serving_chat.engine.check_health()
  File "/usr/local/lib/python3.10/dist-packages/vllm/engine/async_llm_engine.py", line 943, in check_health
    raise AsyncEngineDeadError("Background loop is stopped.")
vllm.engine.async_llm_engine.AsyncEngineDeadError: Background loop is stopped.
gabrielhuang commented 4 months ago

In case it helps others, using max_tokens=1 solved the issue

DarkLight1337 commented 4 months ago

Actually let me reopen this since it appears that we're supposed to specifically allow max_tokens=0 when echo=True.

https://github.com/vllm-project/vllm/blob/main/vllm/entrypoints/openai/protocol.py#L399

github-actions[bot] commented 4 weeks ago

This issue has been automatically marked as stale because it has not had any activity within 90 days. It will be automatically closed if no further activity occurs within 30 days. Leave a comment if you feel this issue should remain open. Thank you!