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vLLM/vllm/v1/engine/llm_engine.py
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afeldman-nmrshaw@neuralmagic.com <rshaw@neuralmagic.com>Nick Hill
0630d4537a [V1] Logprobs and prompt logprobs support (#9880)
This PR is adding support for sample logprobs & prompt logprobs to vLLM v1.

New behavior:

- During model execution, model runner computes sample logprobs (if user-provided logprobs setting is not None) and prompt logprobs (if user-provided prompt_logprobs setting is not None). For both sample and prompt logprobs, the engine core returns 3 vectors: token ids, token logprob values, token ranks. Ranks reflect tokens' 1-indexed positions in the vocabulary vector after sorting the vocabulary by log probability in descending order.
- In scheduler.update_from_output(), sample and prompt logprobs are incorporated into the EngineCoreOutput data structure which is transferred to the engine client. If multiprocessing is enabled, then sample and prompt logprobs will be (de)serialized when the EngineCoreOutput data structure is (de)serialized.
- During output processing, the LogprobsProcessor transforms the triplet of token ids, token logprobs values, and token ranks into the OpenAI-compatible List[Dict[token id,Logprob]] format (for sample and prompt logprobs respectively.)
- Each Logprob instance (whether sample- or prompt-) consists of a token's log-probability, rank, and detokenized string representation. Note that logprob detokenization is handled by the LogprobsProcessor not the detokenizer.

Signed-off-by: Andrew Feldman <afeldman@neuralmagic.com>
Signed-off-by: Nick Hill <nhill@redhat.com>
Signed-off-by: rshaw@neuralmagic.com <rshaw@neuralmagic.com>


Co-authored-by: rshaw@neuralmagic.com <rshaw@neuralmagic.com>
Co-authored-by: Nick Hill <nhill@redhat.com>
2025-02-07 07:26:20 -08:00

186 lines
7.0 KiB
Python

# SPDX-License-Identifier: Apache-2.0
from typing import Dict, List, Mapping, Optional, Type, Union
from typing_extensions import TypeVar
from vllm.config import VllmConfig
from vllm.engine.arg_utils import EngineArgs
from vllm.engine.metrics_types import StatLoggerBase
from vllm.envs import VLLM_ENABLE_V1_MULTIPROCESSING
from vllm.inputs import INPUT_REGISTRY, InputRegistry, PromptType
from vllm.logger import init_logger
from vllm.lora.request import LoRARequest
from vllm.multimodal import MULTIMODAL_REGISTRY, MultiModalRegistry
from vllm.outputs import RequestOutput
from vllm.pooling_params import PoolingParams
from vllm.prompt_adapter.request import PromptAdapterRequest
from vllm.sampling_params import SamplingParams
from vllm.transformers_utils.tokenizer_group import (
BaseTokenizerGroup, init_tokenizer_from_configs)
from vllm.usage.usage_lib import UsageContext
from vllm.v1.engine.core_client import EngineCoreClient
from vllm.v1.engine.output_processor import OutputProcessor
from vllm.v1.engine.processor import Processor
from vllm.v1.executor.abstract import Executor
logger = init_logger(__name__)
_G = TypeVar("_G", bound=BaseTokenizerGroup, default=BaseTokenizerGroup)
class LLMEngine:
"""Legacy LLMEngine for backwards compatibility."""
def __init__(
self,
vllm_config: VllmConfig,
executor_class: Type[Executor],
log_stats: bool,
usage_context: UsageContext = UsageContext.ENGINE_CONTEXT,
stat_loggers: Optional[Dict[str, StatLoggerBase]] = None,
input_registry: InputRegistry = INPUT_REGISTRY,
mm_registry: MultiModalRegistry = MULTIMODAL_REGISTRY,
use_cached_outputs: bool = False,
multiprocess_mode: bool = False,
) -> None:
self.model_config = vllm_config.model_config
self.cache_config = vllm_config.cache_config
# Tokenizer (+ ensure liveness if running in another process).
self.tokenizer = init_tokenizer_from_configs(
model_config=vllm_config.model_config,
scheduler_config=vllm_config.scheduler_config,
parallel_config=vllm_config.parallel_config,
lora_config=vllm_config.lora_config)
self.tokenizer.ping()
# Processor (convert Inputs --> EngineCoreRequests)
self.processor = Processor(model_config=vllm_config.model_config,
cache_config=vllm_config.cache_config,
lora_config=vllm_config.lora_config,
tokenizer=self.tokenizer,
input_registry=input_registry,
mm_registry=mm_registry)
# OutputProcessor (convert EngineCoreOutputs --> RequestOutput).
self.output_processor = OutputProcessor(self.tokenizer,
log_stats=False)
# EngineCore (gets EngineCoreRequests and gives EngineCoreOutputs)
self.engine_core = EngineCoreClient.make_client(
multiprocess_mode=multiprocess_mode,
asyncio_mode=False,
vllm_config=vllm_config,
executor_class=executor_class,
)
@classmethod
def from_engine_args(
cls,
engine_args: EngineArgs,
usage_context: UsageContext = UsageContext.ENGINE_CONTEXT,
stat_loggers: Optional[Dict[str, StatLoggerBase]] = None,
enable_multiprocessing: bool = False,
) -> "LLMEngine":
"""Creates an LLM engine from the engine arguments."""
# Create the engine configs.
vllm_config = engine_args.create_engine_config(usage_context)
executor_class = Executor.get_class(vllm_config)
if VLLM_ENABLE_V1_MULTIPROCESSING:
logger.debug("Enabling multiprocessing for LLMEngine.")
enable_multiprocessing = True
# Create the LLMEngine.
return cls(vllm_config=vllm_config,
executor_class=executor_class,
log_stats=not engine_args.disable_log_stats,
usage_context=usage_context,
stat_loggers=stat_loggers,
multiprocess_mode=enable_multiprocessing)
def get_num_unfinished_requests(self) -> int:
return self.output_processor.get_num_unfinished_requests()
def has_unfinished_requests(self) -> bool:
return self.output_processor.has_unfinished_requests()
@classmethod
def validate_outputs(cls, outputs, output_type):
return outputs
def abort_request(self, request_ids: List[str]) -> None:
"""Remove request_ids from EngineCore and Detokenizer."""
self.engine_core.abort_requests(request_ids)
self.output_processor.abort_requests(request_ids)
def add_request(
self,
request_id: str,
prompt: PromptType,
params: Union[SamplingParams, PoolingParams],
arrival_time: Optional[float] = None,
lora_request: Optional[LoRARequest] = None,
trace_headers: Optional[Mapping[str, str]] = None,
prompt_adapter_request: Optional[PromptAdapterRequest] = None,
priority: int = 0,
) -> None:
# 1) Process raw inputs into the request.
request = self.processor.process_inputs(request_id, prompt, params,
arrival_time, lora_request,
trace_headers,
prompt_adapter_request,
priority)
# 2) Make a new RequestState and queue.
self.output_processor.add_request(request)
# 3) Add the request to EngineCore.
self.engine_core.add_request(request)
def step(self) -> List[RequestOutput]:
# 1) Get EngineCoreOutput from the EngineCore.
outputs = self.engine_core.get_output()
# 2) Process EngineCoreOutputs.
processed_outputs = self.output_processor.process_outputs(
outputs.outputs)
# 3) Abort any reqs that finished due to stop strings.
self.engine_core.abort_requests(processed_outputs.reqs_to_abort)
return processed_outputs.request_outputs
def get_model_config(self):
return self.model_config
def start_profile(self):
self.engine_core.profile(True)
def stop_profile(self):
self.engine_core.profile(False)
def reset_prefix_cache(self):
self.engine_core.reset_prefix_cache()
def get_tokenizer_group(
self,
group_type: Type[_G] = BaseTokenizerGroup,
) -> _G:
tokenizer_group = self.tokenizer
if tokenizer_group is None:
raise ValueError("Unable to get tokenizer because "
"skip_tokenizer_init is True")
if not isinstance(tokenizer_group, group_type):
raise TypeError("Invalid type of tokenizer group. "
f"Expected type: {group_type}, but "
f"found type: {type(tokenizer_group)}")
return tokenizer_group