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vllm-omni/vllm_omni/diffusion/request.py
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Python

# adapted from sglang and fastvideo
# SPDX-License-Identifier: Apache-2.0
# SPDX-FileCopyrightText: Copyright contributors to the vLLM-Omni project
from __future__ import annotations
import random
from dataclasses import dataclass, field
from typing import TYPE_CHECKING, Any
from vllm_omni.inputs.data import OmniDiffusionSamplingParams, OmniPromptType
if TYPE_CHECKING:
from vllm_omni.diffusion.diffusion_kv.request import DiffusionKVRequest
DUMMY_DIFFUSION_REQUEST_ID = "dummy_req_id"
_DUMMY_DIFFUSION_REQUEST_ID_PREFIX = f"{DUMMY_DIFFUSION_REQUEST_ID}/"
def resolve_video_num_frames(
num_frames: int | None,
*,
default_num_frames: int,
is_dummy_run: bool,
) -> int:
"""Resolve the shared image-model frame sentinel for a video pipeline.
``OmniDiffusionSamplingParams`` defaults ``num_frames`` to one for image
models, so an omitted video API field reaches model code as ``1``. Video
pipelines with a different default must materialize it at their boundary.
Startup profiling intentionally requests one frame, however, and must stay
lightweight.
"""
if num_frames is None or (num_frames == 1 and not is_dummy_run):
return default_num_frames
return num_frames
@dataclass
class OmniDiffusionRequest:
"""
Input payload for a single diffusion request.
This dataclass contains the prompt and sampling parameters for the diffusion pipeline
execution. It also contains a request_id for other components to trace this request and its outputs.
The runner wraps one or more requests into a DiffusionRequestBatch before pipeline execution.
"""
# TODO(will): double check that args are separate from server_args
# properly. Also maybe think about providing an abstraction for pipeline
# specific arguments.
# data_type: DataType
prompt: OmniPromptType
sampling_params: OmniDiffusionSamplingParams
request_id: str
kv_sender_info: dict[str, Any] | None = None
payload_sender_info: dict[str, Any] | None = None
# Optional opaque, model-owned input prepared before Scheduler admission.
# Model code validates its concrete type when consuming it on the Worker.
prepared_layout: Any | None = None
# Scheduler-only native-compatible KV requests produced by model
# preprocessing.
# BaseScheduler takes ownership and clears this field before the request is
# sent to a Worker.
diffusion_kv_requests: tuple[DiffusionKVRequest, ...] | None = None
# Optional model-specific condition structure used by request-batch admission.
# This is populated by a pipeline preprocessor before the request reaches
# the scheduler; ``None`` keeps the default behavior for other pipelines.
batch_compatibility_key: tuple[Any, ...] | None = None
# Opaque native vLLM connector parameters. The Orchestrator and Scheduler
# transport this bag without interpreting local pages or block IDs.
kv_transfer_params: dict[str, Any] | None = None
# Worker-populated scheduler reuse boundaries, available before encoding.
kv_computed_tokens: tuple[int, ...] = ()
# A model preprocessor may keep selected requests on the legacy full-forward
# path even when the engine is globally configured for step execution.
use_step_execution: bool = True
# KV-recv wall-clock (ms), set by the runner's _prepare_request_for_forward
# and carried to DiffusionOutput for the vllm_omni:diffusion_kv_load_s metric.
kv_recv_ms: float = 0.0
# Time spent waiting for initial admission by the diffusion scheduler.
scheduler_queue_wait_ms: float | None = None
# Engine-owned shared-memory signal for cooperative full-forward workers.
# Only the engine creates/unlinks it; workers attach readers until return.
cancellation_signal: str | None = field(default=None, repr=False)
def __post_init__(self):
"""Initialize dependent fields after dataclass initialization."""
if not isinstance(self.request_id, str) or not self.request_id:
raise ValueError("OmniDiffusionRequest.request_id must be a non-empty string.")
# When neither a generator nor a seed is provided, assign a random seed
# so that all ranks derive the same generator state.
if self.sampling_params.generator is None and self.sampling_params.seed is None:
self.sampling_params.seed = random.randint(0, 2**31 - 1)
# Detect whether the caller explicitly provided guidance_scale before
# resolving the omitted value. ``0.0`` is API-valid and must not be
# treated as omission because that would unexpectedly enable CFG in
# pipelines with a model-specific default above zero.
if self.sampling_params.guidance_scale is not None:
self.sampling_params.guidance_scale_provided = True
else:
self.sampling_params.guidance_scale = 1.0
# Set do_classifier_free_guidance based on guidance scale and negative prompt
if self.sampling_params.guidance_scale > 1.0 and (
not isinstance(self.prompt, str) and self.prompt.get("negative_prompt")
):
self.sampling_params.do_classifier_free_guidance = True
# Detect whether the caller explicitly provided guidance_scale_2
# BEFORE auto-filling it. Pipelines with a model-specific second
# guidance default (e.g. Boogu image_guidance_scale=1.0) must be able
# to tell an explicit value apart from the guidance_scale fallback.
if self.sampling_params.guidance_scale_2 is not None:
self.sampling_params.guidance_scale_2_provided = True
# Auto-fill guidance_scale_2 from the (now-resolved) guidance_scale
# so downstream code always has a valid value.
if self.sampling_params.guidance_scale_2 is None:
self.sampling_params.guidance_scale_2 = self.sampling_params.guidance_scale
def is_dummy_run(self) -> bool:
return self.is_dummy_run_request_id(self.request_id)
@classmethod
def is_dummy_run_request_id(cls, request_id: str | None) -> bool:
return request_id == DUMMY_DIFFUSION_REQUEST_ID or (
isinstance(request_id, str) and request_id.startswith(_DUMMY_DIFFUSION_REQUEST_ID_PREFIX)
)