[V1] Refactor parallel sampling support (#13774)

Signed-off-by: Mark McLoughlin <markmc@redhat.com>
This commit is contained in:
Mark McLoughlin 2025-03-03 16:15:27 +00:00 committed by GitHub
parent f35f8e2242
commit 4167252eaf
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5 changed files with 198 additions and 461 deletions

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@ -25,7 +25,7 @@ from vllm.usage.usage_lib import UsageContext
from vllm.utils import cdiv, kill_process_tree
from vllm.v1.engine.core_client import EngineCoreClient
from vllm.v1.engine.output_processor import OutputProcessor
from vllm.v1.engine.parallel_sampling import generate_parallel_sampling_async
from vllm.v1.engine.parallel_sampling import ParentRequest
from vllm.v1.engine.processor import Processor
from vllm.v1.executor.abstract import Executor
from vllm.v1.metrics.loggers import (LoggingStatLogger, PrometheusStatLogger,
@ -145,25 +145,30 @@ class AsyncLLM(EngineClient):
"""Add new request to the AsyncLLM."""
# 1) Create a new output queue for the request.
if self.output_processor.is_request_active(request_id):
raise ValueError(f"Request id {request_id} already running.")
queue: asyncio.Queue[RequestOutput] = asyncio.Queue()
# 2) Convert Input --> Request.
request = self.processor.process_inputs(request_id, prompt, params,
arrival_time, lora_request,
trace_headers,
prompt_adapter_request,
priority)
# 2) Fan out child requests (for n>1)
parent_req = ParentRequest.from_params(request_id, params)
n = params.n if isinstance(params, SamplingParams) else 1
for idx in range(n):
if parent_req is not None:
request_id, params = parent_req.get_child_info(idx)
# 3) Add the request to OutputProcessor (this process).
self.output_processor.add_request(request, queue)
# 3) Convert Input --> Request.
request = self.processor.process_inputs(request_id, prompt, params,
arrival_time, lora_request,
trace_headers,
prompt_adapter_request,
priority)
# 4) Add the EngineCoreRequest to EngineCore (separate process).
await self.engine_core.add_request_async(request)
# 4) Add the request to OutputProcessor (this process).
self.output_processor.add_request(request, parent_req, idx, queue)
if self.log_requests:
logger.info("Added request %s.", request_id)
# 5) Add the EngineCoreRequest to EngineCore (separate process).
await self.engine_core.add_request_async(request)
if self.log_requests:
logger.info("Added request %s.", request_id)
return queue
@ -172,7 +177,7 @@ class AsyncLLM(EngineClient):
# requests we don't need to send multiple messages to core proc,
# and so we don't need multiple streams which then get
# re-multiplexed in the API server anyhow.
async def _generate(
async def generate(
self,
prompt: PromptType,
sampling_params: SamplingParams,
@ -243,30 +248,6 @@ class AsyncLLM(EngineClient):
await self.abort(request_id)
raise
def generate(
self,
prompt: PromptType,
sampling_params: SamplingParams,
request_id: str,
lora_request: Optional[LoRARequest] = None,
trace_headers: Optional[Mapping[str, str]] = None,
prompt_adapter_request: Optional[PromptAdapterRequest] = None,
priority: int = 0,
) -> AsyncGenerator[RequestOutput, None]:
kwargs = dict(prompt=prompt,
sampling_params=sampling_params,
request_id=request_id,
lora_request=lora_request,
trace_headers=trace_headers,
prompt_adapter_request=prompt_adapter_request,
priority=priority)
if sampling_params.n is None or sampling_params.n == 1:
return self._generate(**kwargs)
else:
# Special handling for parallel sampling requests
return generate_parallel_sampling_async(generate=self._generate,
**kwargs)
async def _run_output_handler(self):
"""Background loop: pulls from EngineCore and pushes to AsyncStreams."""

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@ -22,7 +22,7 @@ from vllm.transformers_utils.tokenizer_group import (
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.parallel_sampling import SyncParallelSamplingManager
from vllm.v1.engine.parallel_sampling import ParentRequest
from vllm.v1.engine.processor import Processor
from vllm.v1.executor.abstract import Executor
@ -50,9 +50,6 @@ class LLMEngine:
self.model_config = vllm_config.model_config
self.cache_config = vllm_config.cache_config
# Bookkeeping for parallel sampling requests
self.parallel_manager = SyncParallelSamplingManager()
# important: init dp group before init the engine_core
self.parallel_config = vllm_config.parallel_config
self.dp_enabled = self.parallel_config.data_parallel_size > 1 # noqa
@ -120,8 +117,7 @@ class LLMEngine:
multiprocess_mode=enable_multiprocessing)
def get_num_unfinished_requests(self) -> int:
return self.parallel_manager.get_num_unfinished_requests(
self.output_processor.get_num_unfinished_requests())
return self.output_processor.get_num_unfinished_requests()
def has_unfinished_requests(self) -> bool:
has_unfinished = self.output_processor.has_unfinished_requests()
@ -157,48 +153,25 @@ class LLMEngine:
prompt_adapter_request: Optional[PromptAdapterRequest] = None,
priority: int = 0,
) -> None:
"""Add request."""
kwargs = dict(request_id=request_id,
prompt=prompt,
params=params,
arrival_time=arrival_time,
lora_request=lora_request,
trace_headers=trace_headers,
prompt_adapter_request=prompt_adapter_request,
priority=priority)
# Handle parallel sampling requests differently.
if params is None or isinstance(params,
PoolingParams) or params.n == 1:
self._add_request(**kwargs)
else:
# Special handling for parallel sampling requests
self.parallel_manager.add_request_parallel_sampling(
add_request=self._add_request, **kwargs)
# 1) Fan out child requests (for n>1)
parent_req = ParentRequest.from_params(request_id, params)
n = params.n if isinstance(params, SamplingParams) else 1
for idx in range(n):
if parent_req is not None:
request_id, params = parent_req.get_child_info(idx)
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:
"""Add request, `n=1`"""
# 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) 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) Make a new RequestState and queue.
self.output_processor.add_request(request, parent_req, idx)
# 3) Add the request to EngineCore.
self.engine_core.add_request(request)
# 3) Add the request to EngineCore.
self.engine_core.add_request(request)
def step(self) -> list[RequestOutput]:
@ -217,10 +190,7 @@ class LLMEngine:
# 3) Abort any reqs that finished due to stop strings.
self.engine_core.abort_requests(processed_outputs.reqs_to_abort)
request_outputs = processed_outputs.request_outputs
# 4) Process unfinished parallel sampling requests
return self.parallel_manager.step(request_outputs)
return processed_outputs.request_outputs
def get_model_config(self):
return self.model_config

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@ -4,13 +4,14 @@ import asyncio
from dataclasses import dataclass
from typing import Optional, Union
from vllm.outputs import RequestOutput
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 BaseTokenizerGroup
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)
@ -27,6 +28,8 @@ 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],
@ -38,6 +41,8 @@ class RequestState:
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
@ -56,11 +61,15 @@ class RequestState:
cls,
tokenizer: AnyTokenizer,
request: EngineCoreRequest,
parent_req: Optional[ParentRequest],
request_index: int,
queue: Optional[asyncio.Queue[RequestOutput]],
log_stats: bool,
) -> "RequestState":
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,
@ -79,6 +88,88 @@ class RequestState:
log_stats=log_stats,
)
def make_request_output(
self,
new_token_ids: list[int],
finish_reason: Optional[FinishReason],
stop_reason: Union[int, str, None],
) -> Optional[RequestOutput]:
finished = finish_reason is not None
output_kind = self.output_kind
final_only = output_kind == RequestOutputKind.FINAL_ONLY
# In follow up, we will switch to invariant where EngineCore
# does not stream partial prefills.
if not finished and (self.is_prefilling or final_only):
# Only the final output is required in FINAL_ONLY mode.
return None
def new_request_output(request_id: str) -> RequestOutput:
return self._new_request_output(request_id, finished)
completion_output = self._new_completion_output(
new_token_ids, finish_reason, stop_reason)
if self.parent_req is not None:
return self.parent_req.make_request_output(final_only,
completion_output,
new_request_output)
request_output = new_request_output(self.request_id)
request_output.outputs.append(completion_output)
return request_output
def _new_request_output(
self,
request_id: str,
finished: bool,
) -> 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=[],
finished=finished,
)
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."""
@ -93,9 +184,6 @@ class OutputProcessor:
self.request_states: dict[str, RequestState] = {}
self.lora_states = LoRARequestStates()
def is_request_active(self, request_id: str) -> bool:
return request_id in self.request_states
def get_num_unfinished_requests(self):
return len(self.request_states)
@ -114,6 +202,8 @@ class OutputProcessor:
def add_request(
self,
request: EngineCoreRequest,
parent_req: Optional[ParentRequest] = None,
request_index: int = 0,
queue: Optional[asyncio.Queue[RequestOutput]] = None,
) -> None:
request_id = request.request_id
@ -123,6 +213,8 @@ class OutputProcessor:
req_state = RequestState.from_new_request(
tokenizer=self.tokenizer.get_lora_tokenizer(request.lora_request),
request=request,
parent_req=parent_req,
request_index=request_index,
queue=queue,
log_stats=self.log_stats)
self.request_states[request_id] = req_state
@ -202,8 +294,8 @@ class OutputProcessor:
req_state.logprobs_processor.update_from_output(engine_core_output)
# 4) Create and handle RequestOutput objects.
if request_output := self._make_request_output(
req_state, new_token_ids, finish_reason, stop_reason):
if request_output := req_state.make_request_output(
new_token_ids, finish_reason, stop_reason):
if req_state.queue is not None:
# AsyncLLM: put into queue for handling by generate().
req_state.queue.put_nowait(request_output)
@ -211,18 +303,17 @@ class OutputProcessor:
# LLMEngine: return list of RequestOutputs.
request_outputs.append(request_output)
# Free completed requests.
if request_output.finished:
self.request_states.pop(req_id)
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)
# Free completed requests.
if finish_reason is not None:
self.request_states.pop(req_id)
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, request_output,
finish_reason,
iteration_stats)
# Track per-request stats
self._update_stats_from_finished(req_state, finish_reason,
iteration_stats)
self.lora_states.update_iteration_stats(iteration_stats)
@ -249,7 +340,6 @@ class OutputProcessor:
req_state.stats, lora_stats)
def _update_stats_from_finished(self, req_state: RequestState,
request_output: RequestOutput,
finish_reason: Optional[FinishReason],
iteration_stats: Optional[IterationStats]):
if iteration_stats is None:
@ -257,55 +347,8 @@ class OutputProcessor:
assert finish_reason is not None
assert req_state.stats is not None
iteration_stats.update_from_finished_request(finish_reason,
request_output,
req_state.stats)
iteration_stats.update_from_finished_request(
finish_reason=finish_reason,
num_prompt_tokens=len(req_state.prompt_token_ids),
req_stats=req_state.stats)
self.lora_states.finish_request(req_state)
@staticmethod
def _make_request_output(
request_state: RequestState,
new_token_ids: list[int],
finish_reason: Optional[FinishReason],
stop_reason: Union[int, str, None],
) -> Optional[RequestOutput]:
finished = finish_reason is not None
output_kind = request_state.output_kind
# In follow up, we will switch to invariant where EngineCore
# does not stream partial prefills.
if not finished and (request_state.is_prefilling
or output_kind == RequestOutputKind.FINAL_ONLY):
# Only the final output is required in FINAL_ONLY mode.
return None
detokenizer = request_state.detokenizer
logprobs_processor = request_state.logprobs_processor
delta = output_kind == RequestOutputKind.DELTA
logprobs = logprobs_processor.logprobs
if delta:
if logprobs:
logprobs = logprobs[-len(new_token_ids):]
# Side effect: logprobs processor forgets prompt logprobs
prompt_logprobs = logprobs_processor.pop_prompt_logprobs()
else:
prompt_logprobs = logprobs_processor.prompt_logprobs
request_output = RequestOutput.new(
request_id=request_state.request_id,
prompt=request_state.prompt,
prompt_token_ids=request_state.prompt_token_ids,
text=detokenizer.get_next_output_text(finished, delta),
token_ids=new_token_ids if delta else detokenizer.output_token_ids,
logprobs=logprobs,
prompt_logprobs=prompt_logprobs,
cumulative_logprob=logprobs_processor.cumulative_logprob,
finished=finished,
)
if finished:
completion_output = request_output.outputs[0]
completion_output.finish_reason = str(finish_reason)
completion_output.stop_reason = stop_reason
return request_output

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@ -1,69 +1,46 @@
# SPDX-License-Identifier: Apache-2.0
from collections.abc import AsyncGenerator, Mapping
from copy import copy
from typing import Optional, Protocol, Union
from typing import Callable, Optional, Union
from vllm.inputs import PromptType
from vllm.lora.request import LoRARequest
from vllm.outputs import RequestOutput
from vllm.outputs import CompletionOutput, RequestOutput
from vllm.pooling_params import PoolingParams
from vllm.prompt_adapter.request import PromptAdapterRequest
from vllm.sampling_params import RequestOutputKind, SamplingParams
from vllm.utils import merge_async_iterators
from vllm.sampling_params import SamplingParams
class AsyncGenerateMethodType(Protocol):
def __call__(self,
prompt: PromptType,
sampling_params: SamplingParams,
request_id: str,
lora_request: Optional[LoRARequest] = None,
trace_headers: Optional[Mapping[str, str]] = None,
prompt_adapter_request: Optional[PromptAdapterRequest] = None,
priority: int = 0) -> AsyncGenerator[RequestOutput, None]:
...
class SyncAddRequestMethodType(Protocol):
def __call__(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:
...
class ParallelSamplingRequest:
class ParentRequest:
"""Info, state & processing for parallel sampling request.
Store parent request ID and sampling params.
Facilitate generating child request sampling params.
Transform child request outputs into parent request
outputs.
When stream mode is disabled, then `self.request_output`
aggregates child request completions.
"""
request_id: str
sampling_params: SamplingParams
# To aggregate child completions when not streaming
output_aggregator: Optional[RequestOutput]
# To efficiently obtain child sampling params
cached_child_sampling_params: Optional[SamplingParams]
request_output: Optional[RequestOutput]
num_finished_completions: int
def __init__(self, request_id: str,
sampling_params: SamplingParams) -> None:
self.request_id = request_id
self.sampling_params = sampling_params
self.output_aggregator = None
self.cached_child_sampling_params = None
self.request_output = None
self.num_finished_completions = 0
@classmethod
def from_params(
cls,
request_id: str,
params: Union[SamplingParams, PoolingParams],
) -> Optional['ParentRequest']:
if not isinstance(params, SamplingParams) or params.n == 1:
return None
return cls(request_id, params)
def _get_child_sampling_params(
self,
@ -96,47 +73,6 @@ class ParallelSamplingRequest:
child_sampling_params.seed = seed + index
return child_sampling_params
def _add_output(
self,
child_req_output: RequestOutput,
index: int,
) -> None:
"""Aggregate a parallel sampling child
request output.
Non-stream-mode (`output_kind == FINAL_ONLY`)
only. Inject correct parent request ID and
completion index.
Args:
child_req_output: a single request output
from a parallel sampling
child request.
index: index within `n` child
"""
self.num_finished_completions += 1
new_completion = child_req_output.outputs[0]
new_completion.index = index
if self.request_output is None:
# Save the first request output; reinstate
# original request ID; metrics are not
# supported for parallel sampling
child_req_output.request_id = self.request_id
child_req_output.metrics = None
self.request_output = child_req_output
else:
# Aggregate additional completion into request output
# Note: will be sorted by index later
self.request_output.outputs.append(new_completion)
def _get_final_request_output(self) -> RequestOutput:
"""Invariant: parent completion outputs sorted by index"""
assert self.request_output is not None
self.request_output.finished = True
self.request_output.outputs = sorted(self.request_output.outputs,
key=lambda x: x.index)
return self.request_output
def get_child_info(self, index: int) -> tuple[str, SamplingParams]:
"""Get child request ID and sampling params.
@ -149,227 +85,35 @@ class ParallelSamplingRequest:
return (f"{index}_{self.request_id}",
self._get_child_sampling_params(index))
def process_output(
self,
child_req_output: RequestOutput,
index: int,
) -> Optional[RequestOutput]:
"""Filter, aggregate and transform parallel sampling
child request outputs.
If the parent request has `stream=false`
(`output_kind == FINAL_ONLY`), each child will also have
`output_kind == FINAL_ONLY`. All child request outputs
must be aggregated into a single request output, with
multiple completions. This request output is only returned
once `n` completions are aggregated.
If the parent request has `stream=true`
(`output_kind == DELTA`), each child will also have
`output_kind == DELTA`. All child request outputs
must be streamed directly to the caller.
Args:
child_req_output: a single child request output
index: index within `n` child requests
Returns:
`None`, unless a processed request output is ready to
send back to the caller.
"""
if self.output_kind != RequestOutputKind.FINAL_ONLY:
# stream=true: return child completions immediately
child_req_output.request_id = self.request_id
child_req_output.outputs[0].index = index
if child_req_output.finished:
# Parent request is complete if all child requests are
# complete.
self.num_finished_completions += 1
child_req_output.finished = (
self.num_finished_completions == self.n)
return child_req_output
# stream=false: aggregate child completions
self._add_output(child_req_output, index)
if self.num_finished_completions == self.n:
# Return aggregated request output after obtaining
# all completions
return self._get_final_request_output()
return None
async def wrap_child_async_generator(
self,
child_gen: AsyncGenerator[RequestOutput, None],
index: int,
) -> AsyncGenerator[RequestOutput, None]:
"""Output generator for a single parallel sampling
child request.
Each parallel sampling request triggers at
least two child requests. This generator
yields zero or more request outputs to
return to the caller, as they become
available.
Args:
child_gen: generator for child request
outputs.
index: index within the `n` child requests
Returns:
Yields zero or more request outputs to return
to the caller.
"""
async for out in child_gen:
if req_out := self.process_output(out, index):
yield req_out
@property
def n(self) -> int:
return self.sampling_params.n
@property
def output_kind(self) -> RequestOutputKind:
return self.sampling_params.output_kind
class SyncParallelSamplingManager:
def __init__(self):
# Parent req ID -> parent request manager
self.parent_reqs: dict[str, ParallelSamplingRequest] = {}
# Child req ID -> (child req index, parent req ID)
self.child_reqs: dict[str, tuple[int, str]] = {}
def _register_parent_request(self, req: ParallelSamplingRequest) -> None:
"""Register parallel sampling parent request."""
self.parent_reqs[req.request_id] = req
def _register_child_request(self, req_id: str, child_req_id: str,
index: int) -> None:
"""Register parallel sampling child request with parent.
Args:
req_id: parent request ID
child_req_id: child request ID
index: child request index within `n` child requests
"""
self.child_reqs[child_req_id] = (index, req_id)
def get_num_unfinished_requests(self, num_core_reqs: int) -> int:
"""Get the number of unfinished requests, correcting for parallel
sampling.
Args:
num_core_reqs: The number of unfinished requests in the engine core.
Returns:
Number of unfinished requests, where each parallel sampling req
counts as 1
"""
return num_core_reqs + len(self.parent_reqs) - len(self.child_reqs)
def add_request_parallel_sampling(
def make_request_output(
self,
add_request: SyncAddRequestMethodType,
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:
"""Add sync parallel sampling request."""
req = ParallelSamplingRequest(request_id, params)
self._register_parent_request(req)
# Add n child requests with unique request IDs & random seeds and n=1
for idx in range(req.n):
child_req_id, child_params = req.get_child_info(idx)
self._register_child_request(request_id, child_req_id, idx)
add_request(request_id=child_req_id,
prompt=prompt,
params=child_params,
arrival_time=arrival_time,
lora_request=lora_request,
trace_headers=trace_headers,
prompt_adapter_request=prompt_adapter_request,
priority=priority) # type: ignore
final_only: bool,
completion_output: CompletionOutput,
new_request_output: Callable[[str], RequestOutput],
) -> Optional[RequestOutput]:
# Use an existing RequestOutput if we're aggregating
request_output = self.output_aggregator
def step(
self,
outputs: list[RequestOutput],
) -> list[RequestOutput]:
"""Build parallel sampling request outputs.
Extract child request outputs, aggregate them
into parent request output, and return parent
output when complete.
# Make new RequestOutput otherwise
if request_output is None:
request_output = new_request_output(self.request_id)
Do not modify `n=1` requests.
# Add a new completion
request_output.outputs.append(completion_output)
Args:
outputs: step request outputs. Mix of child request
outputs & `n=1` request outputs.
# If not streaming, aggregate until all child requests complete
if final_only and len(request_output.outputs) != self.n:
self.output_aggregator = request_output
return None
Return:
List of parallel sampling parent request outputs &
unmodified `n=1` request outputs passed-thru from input.
"""
if not (self.parent_reqs and outputs):
# Return unmodified
return outputs
agg_outputs = []
for output in outputs:
req_id = output.request_id
if child_req_entry := self.child_reqs.get(req_id, None):
# For each parallel sampling child request output:
(index, parent_req_id) = child_req_entry
req = self.parent_reqs[parent_req_id]
# Update parallel sampling request
if out := req.process_output(output, index):
# Return parent request output if complete;
# cleanup parent request bookkeeping.
agg_outputs.append(out)
del self.parent_reqs[parent_req_id]
# Cleanup child request bookkeeping.
del self.child_reqs[req_id]
else:
# Not a parallel sampling request output
agg_outputs.append(output)
return agg_outputs
# We're done aggregating
self.output_aggregator = None
async def generate_parallel_sampling_async(
generate: AsyncGenerateMethodType,
prompt: PromptType,
sampling_params: SamplingParams,
request_id: str,
lora_request: Optional[LoRARequest] = None,
trace_headers: Optional[Mapping[str, str]] = None,
prompt_adapter_request: Optional[PromptAdapterRequest] = None,
priority: int = 0,
) -> AsyncGenerator[RequestOutput, None]:
"""Generate completions for async parallel sampling requests."""
parent_req = ParallelSamplingRequest(request_id, sampling_params)
# Aggregate generators for n child requests
gens: list[AsyncGenerator[RequestOutput, None]] = []
for idx in range(parent_req.n):
child_req_id, child_params = parent_req.get_child_info(idx)
child_gen = generate(
prompt=prompt,
sampling_params=child_params,
request_id=child_req_id,
lora_request=lora_request,
trace_headers=trace_headers,
prompt_adapter_request=prompt_adapter_request,
priority=priority,
) # type: ignore
gen = parent_req.wrap_child_async_generator(child_gen, idx)
gens.append(gen)
# Merge generators
async for _, out in merge_async_iterators(*gens):
yield out
# Parent completion output list must be sorted by index
request_output.outputs = sorted(request_output.outputs,
key=lambda x: x.index)
return request_output

View File

@ -5,7 +5,6 @@ from dataclasses import dataclass, field
from typing import TYPE_CHECKING, Optional
if TYPE_CHECKING:
from vllm.outputs import RequestOutput
from vllm.v1.engine import EngineCoreEvent, EngineCoreOutput, FinishReason
from vllm.v1.output_processor import RequestState
@ -150,7 +149,7 @@ class IterationStats:
self.num_preempted_reqs += 1
def update_from_finished_request(self, finish_reason: "FinishReason",
request_output: "RequestOutput",
num_prompt_tokens: int,
req_stats: RequestStateStats):
e2e_latency = self._time_since(req_stats.arrival_time)
@ -172,7 +171,7 @@ class IterationStats:
finished_req = \
FinishedRequestStats(finish_reason=finish_reason,
e2e_latency=e2e_latency,
num_prompt_tokens=len(request_output.prompt_token_ids),
num_prompt_tokens=num_prompt_tokens,
num_generation_tokens=req_stats.num_generation_tokens,
queued_time=queued_time,
prefill_time=prefill_time,