vllm/vllm/v1/engine/output_processor.py
Chauncey b046cf792d
[Feature][V1]: suupports cached_tokens in response usage (#18149)
Co-authored-by: simon-mo <xmo@berkeley.edu>
2025-05-23 01:41:03 -07:00

428 lines
16 KiB
Python

# SPDX-License-Identifier: Apache-2.0
import asyncio
from collections.abc import Iterable
from dataclasses import dataclass
from typing import Any, Optional, Union
from vllm.outputs import CompletionOutput, RequestOutput
from vllm.sampling_params import RequestOutputKind
from vllm.transformers_utils.tokenizer import AnyTokenizer
from vllm.transformers_utils.tokenizer_group import TokenizerGroup
from vllm.v1.engine import EngineCoreOutput, EngineCoreRequest, FinishReason
from vllm.v1.engine.detokenizer import IncrementalDetokenizer
from vllm.v1.engine.logprobs import LogprobsProcessor
from vllm.v1.engine.parallel_sampling import ParentRequest
from vllm.v1.metrics.stats import (IterationStats, LoRARequestStates,
RequestStateStats)
class RequestOutputCollector:
"""
Collects streamed RequestOutputs per individual request,
for hand-off to the consuming asyncio generate task.
When streaming deltas, RequestOutputs are merged if the
producer gets ahead of the consumer.
"""
def __init__(self, output_kind: RequestOutputKind):
self.aggregate = output_kind == RequestOutputKind.DELTA
self.output: Optional[Union[RequestOutput, Exception]] = None
self.ready = asyncio.Event()
def put(self, output: Union[RequestOutput, Exception]) -> None:
"""Non-blocking put operation."""
if self.output is None or isinstance(output, Exception):
self.output = output
self.ready.set()
elif isinstance(self.output, RequestOutput):
# This ensures that request outputs with different request indexes
# (if n > 1) do not override each other.
self.output.add(output, aggregate=self.aggregate)
async def get(self) -> RequestOutput:
"""Get operation blocks on put event."""
while (output := self.output) is None:
await self.ready.wait()
self.output = None
self.ready.clear()
if isinstance(output, Exception):
raise output
return output
def get_nowait(self) -> Optional[RequestOutput]:
"""Non-blocking get operation."""
output = self.output
if output is not None:
self.output = None
self.ready.clear()
if isinstance(output, Exception):
raise output
return output
@dataclass
class OutputProcessorOutput:
request_outputs: list[RequestOutput]
reqs_to_abort: list[str]
class RequestState:
def __init__(
self,
request_id: str,
parent_req: Optional[ParentRequest],
request_index: int,
lora_name: Optional[str],
output_kind: RequestOutputKind,
prompt: Optional[str],
prompt_token_ids: list[int],
logprobs_processor: LogprobsProcessor,
detokenizer: IncrementalDetokenizer,
max_tokens_param: Optional[int],
arrival_time: float,
queue: Optional[RequestOutputCollector],
log_stats: bool,
):
self.request_id = request_id
self.parent_req = parent_req
self.request_index = request_index
self.lora_name = lora_name
self.output_kind = output_kind
self.prompt = prompt
self.prompt_token_ids = prompt_token_ids
self.prompt_len = len(prompt_token_ids)
self.logprobs_processor = logprobs_processor
self.detokenizer = detokenizer
self.max_tokens_param = max_tokens_param
self.is_prefilling = True
self.queue = queue
self.stats = RequestStateStats(
arrival_time=arrival_time) if log_stats else None
@classmethod
def from_new_request(
cls,
tokenizer: AnyTokenizer,
request: EngineCoreRequest,
prompt: Optional[str],
parent_req: Optional[ParentRequest],
request_index: int,
queue: Optional[RequestOutputCollector],
log_stats: bool,
) -> "RequestState":
if not request.sampling_params.detokenize:
tokenizer = None
return cls(
request_id=request.request_id,
parent_req=parent_req,
request_index=request_index,
lora_name=(request.lora_request.name
if request.lora_request is not None else None),
output_kind=request.sampling_params.output_kind,
prompt=prompt,
prompt_token_ids=request.prompt_token_ids,
logprobs_processor=LogprobsProcessor.from_new_request(
tokenizer=tokenizer,
request=request,
),
detokenizer=IncrementalDetokenizer.from_new_request(
tokenizer=tokenizer,
request=request,
),
max_tokens_param=(request.sampling_params.max_tokens if
request.sampling_params is not None else None),
arrival_time=request.arrival_time,
queue=queue,
log_stats=log_stats,
)
def make_request_output(
self,
new_token_ids: list[int],
finish_reason: Optional[FinishReason],
stop_reason: Union[int, str, None],
kv_transfer_params: Optional[dict[str, Any]] = None,
num_cached_tokens: int = 0,
) -> Optional[RequestOutput]:
finished = finish_reason is not None
final_only = self.output_kind == RequestOutputKind.FINAL_ONLY
if not finished and final_only:
# Only the final output is required in FINAL_ONLY mode.
return None
completion_output = self._new_completion_output(
new_token_ids, finish_reason, stop_reason)
request_id = self.request_id
if self.parent_req is None:
outputs = [completion_output]
else:
request_id, outputs, finished = self.parent_req.get_outputs(
request_id, completion_output)
if not outputs:
return None
return self._new_request_output(request_id, outputs, finished,
kv_transfer_params, num_cached_tokens)
def _new_request_output(
self,
request_id: str,
outputs: list[CompletionOutput],
finished: bool,
kv_transfer_params: Optional[dict[str, Any]] = None,
num_cached_tokens: int = 0,
) -> RequestOutput:
if self.output_kind == RequestOutputKind.DELTA:
# Side effect: logprobs processor forgets prompt logprobs
prompt_logprobs = self.logprobs_processor.pop_prompt_logprobs()
else:
prompt_logprobs = self.logprobs_processor.prompt_logprobs
return RequestOutput(
request_id=request_id,
prompt=self.prompt,
prompt_token_ids=self.prompt_token_ids,
prompt_logprobs=prompt_logprobs,
outputs=outputs,
finished=finished,
kv_transfer_params=kv_transfer_params,
num_cached_tokens=num_cached_tokens,
)
def _new_completion_output(
self,
token_ids: list[int],
finish_reason: Optional[FinishReason],
stop_reason: Union[int, str, None],
) -> CompletionOutput:
finished = finish_reason is not None
delta = self.output_kind == RequestOutputKind.DELTA
# Prepare text and token_ids, based on delta mode
text = self.detokenizer.get_next_output_text(finished, delta)
if not delta:
token_ids = self.detokenizer.output_token_ids
# Prepare logprobs, based on delta mode
logprobs = self.logprobs_processor.logprobs
if delta and logprobs:
logprobs = logprobs[-len(token_ids):]
return CompletionOutput(
index=self.request_index,
text=text,
token_ids=token_ids,
logprobs=logprobs,
cumulative_logprob=self.logprobs_processor.cumulative_logprob,
finish_reason=str(finish_reason) if finished else None,
stop_reason=stop_reason if finished else None)
class OutputProcessor:
"""Process EngineCoreOutputs into RequestOutputs."""
def __init__(
self,
tokenizer: TokenizerGroup,
log_stats: bool,
):
self.log_stats = log_stats
self.tokenizer = tokenizer
self.request_states: dict[str, RequestState] = {}
self.parent_requests: dict[str, ParentRequest] = {}
self.lora_states = LoRARequestStates()
def get_num_unfinished_requests(self):
return len(self.request_states)
def has_unfinished_requests(self) -> bool:
return len(self.request_states) > 0
def propagate_error(self, e: Exception):
"""Propagate error to all generate() tasks."""
for _, state in self.request_states.items():
assert state.queue is not None
state.queue.put(e)
def abort_requests(
self,
request_ids: Iterable[str],
) -> list[str]:
request_ids_to_abort = []
for request_id in request_ids:
req_state = self.request_states.pop(request_id, None)
if req_state is not None:
self.lora_states.abort_request(req_state)
request_ids_to_abort.append(request_id)
else:
parent = self.parent_requests.pop(request_id, None)
if parent and parent.child_requests:
self.abort_requests(parent.child_requests)
request_ids_to_abort.extend(parent.child_requests)
return request_ids_to_abort
def add_request(
self,
request: EngineCoreRequest,
prompt: Optional[str],
parent_req: Optional[ParentRequest] = None,
request_index: int = 0,
queue: Optional[RequestOutputCollector] = None,
) -> None:
request_id = request.request_id
if request_id in self.request_states:
raise ValueError(f"Request id {request_id} already running.")
req_state = RequestState.from_new_request(
tokenizer=self.tokenizer.get_lora_tokenizer(request.lora_request),
request=request,
prompt=prompt,
parent_req=parent_req,
request_index=request_index,
queue=queue,
log_stats=self.log_stats)
self.request_states[request_id] = req_state
self.lora_states.add_request(req_state)
if parent_req:
self.parent_requests[parent_req.request_id] = parent_req
def process_outputs(
self,
engine_core_outputs: list[EngineCoreOutput],
engine_core_timestamp: Optional[float] = None,
iteration_stats: Optional[IterationStats] = None,
) -> OutputProcessorOutput:
"""
Process the EngineCoreOutputs:
1) Compute stats for logging
2) Detokenize
3) Create and handle RequestOutput objects:
* If there is a queue (for usage with AsyncLLM),
put the RequestOutput objects into the queue for
handling by the per-request generate() tasks.
* If there is no queue (for usage with LLMEngine),
return a list of RequestOutput objects.
NOTE FOR DEVELOPERS
vLLM V1 minimizes the number of python loops over the full
batch to ensure system overheads are minimized. This is the
only function that should loop over EngineCoreOutputs.
If you need to touch every element of the batch, do it from
within the loop below.
"""
request_outputs: list[RequestOutput] = []
reqs_to_abort: list[str] = []
for engine_core_output in engine_core_outputs:
req_id = engine_core_output.request_id
req_state = self.request_states.get(req_id)
if req_state is None:
# Ignore output for already-aborted request.
continue
# 1) Compute stats for this iteration.
self._update_stats_from_output(req_state, engine_core_output,
engine_core_timestamp,
iteration_stats)
new_token_ids = engine_core_output.new_token_ids
finish_reason = engine_core_output.finish_reason
stop_reason = engine_core_output.stop_reason
kv_transfer_params = engine_core_output.kv_transfer_params
num_cached_tokens = engine_core_output.num_cached_tokens
req_state.is_prefilling = False
# 2) Detokenize the token ids into text and perform stop checks.
stop_string = req_state.detokenizer.update(
new_token_ids, finish_reason == FinishReason.STOP)
if stop_string:
finish_reason = FinishReason.STOP
stop_reason = stop_string
# 3) Compute sample and prompt logprobs for request, if required.
req_state.logprobs_processor.update_from_output(engine_core_output)
# 4) Create and handle RequestOutput objects.
if request_output := req_state.make_request_output(
new_token_ids, finish_reason, stop_reason,
kv_transfer_params, num_cached_tokens):
if req_state.queue is not None:
# AsyncLLM: put into queue for handling by generate().
req_state.queue.put(request_output)
else:
# LLMEngine: return list of RequestOutputs.
request_outputs.append(request_output)
# Free completed requests.
if finish_reason is not None:
self.request_states.pop(req_id)
# Remove parent request if applicable.
parent_req = req_state.parent_req
if parent_req and not parent_req.child_requests:
self.parent_requests.pop(parent_req.request_id, None)
if not engine_core_output.finished:
# If req not finished in EngineCore, but Detokenizer
# detected stop string, abort needed in EngineCore.
reqs_to_abort.append(req_id)
# Track per-request stats
self._update_stats_from_finished(req_state, finish_reason,
iteration_stats)
self.lora_states.update_iteration_stats(iteration_stats)
return OutputProcessorOutput(
request_outputs=request_outputs,
reqs_to_abort=reqs_to_abort,
)
def _update_stats_from_output(self, req_state: RequestState,
engine_core_output: EngineCoreOutput,
engine_core_timestamp: Optional[float],
iteration_stats: Optional[IterationStats]):
if iteration_stats is None:
return
lora_stats = self.lora_states.get_stats(req_state)
assert engine_core_timestamp is not None
assert req_state.stats is not None
iteration_stats.update_from_output(engine_core_output,
engine_core_timestamp,
req_state.is_prefilling,
req_state.prompt_len,
req_state.stats, lora_stats)
def _update_stats_from_finished(self, req_state: RequestState,
finish_reason: Optional[FinishReason],
iteration_stats: Optional[IterationStats]):
if iteration_stats is None:
return
assert finish_reason is not None
assert req_state.stats is not None
iteration_stats.update_from_finished_request(
finish_reason=finish_reason,
num_prompt_tokens=len(req_state.prompt_token_ids),
max_tokens_param=req_state.max_tokens_param,
req_stats=req_state.stats)
self.lora_states.finish_request(req_state)
ParentRequest.observe_finished_request(
req_state.parent_req, iteration_stats,
req_state.stats.num_generation_tokens)