Files
hao-ai-lab-FastVideo/v2/forward_context.py
T
SolitaryThinker b2d55a7ba0 [refactor] v2: full vendor cutover — copy fastvideo modeling + layer code into v2 (zero fastvideo imports)
Replace the re-export stubs with real vendored copies of the fastvideo modeling
+ layer + supporting infra, for the kept diffusion models (wan21, wan_causal,
ltx2, flux2, matrixgame2). v2 now imports ZERO `fastvideo.*` — it is
self-contained. (bagel/qwen_omni load from vllm_omni, an external pkg, not
fastvideo; cosmos3's load_id was already dangling — both out of scope here.)

Vendored (cp + `sed fastvideo. -> v2.`):
- models/  the 5 models' nn.Module dits/vaes/encoders/audio/upsamplers + the
           component loader/ + the lazy class registry (other families' rows are
           dormant/lazy — only the 5 resolve).
- layers/ attention/ platforms/ distributed/ configs/ logging_utils/ hooks/
  third_party/pynvml + top-level forward_context/fastvideo_args/envs/logger/
  utils/version — copied verbatim (layers et al. 'as is').
- api/  slimmed to schema + results (the VideoGenerator's config dataclasses);
  the fastvideo parser/presets/overrides (which pull the pipeline runtime) are
  intentionally NOT vendored — v2 has its own runtime/loop.

Decoupling surgery (cut the loader's coupling to the fastvideo runtime):
- configs/pipeline_registry.py (vendored from fastvideo/registry.py, renamed to
  avoid colliding with v2/registry.py): dropped the _register_presets() auto-call
  and matrixgame3 (removed model); config-class resolution preserved.
- configs/pipelines/__init__.py: dropped the registry back-edge (fixes an import
  cycle) — base.py imports the registry lazily where used.
- torch_backend: load_component now uses v2.models.loader.

The only remaining external 'fastvideo*' refs are `fastvideo_kernel` (the
separate optional CUDA-kernel pkg for sparse/MoBA attention) — guarded; the dense
TORCH_SDPA path v2 uses never imports it.

Vendored subtrees added to the pre-commit exclude (faithful copies, mirroring the
existing fastvideo/models exclusion — not re-linted, to stay re-syncable).

Verified: grep finds zero fastvideo-package imports in v2/; Wan2.1 T2V on H100 is
BIT-IDENTICAL to the fastvideo-backed path (same .npy SHA256, byte-for-byte); CPU
mini 156 (154 passed + 2 env-skipped on x86, torch present). Backup: branch v2_backup.
2026-07-04 17:15:34 +00:00

99 lines
3.8 KiB
Python

# SPDX-License-Identifier: Apache-2.0
# Adapted from vllm: https://github.com/vllm-project/vllm/blob/v0.7.3/vllm/forward_context.py
import time
from collections import defaultdict
from contextlib import contextmanager
from dataclasses import dataclass
from typing import TYPE_CHECKING, Optional
import torch
from v2.logger import init_logger
if TYPE_CHECKING:
from v2.attention import AttentionMetadata
from v2.pipelines import ForwardBatch
logger = init_logger(__name__)
# TODO(will): check if this is needed
# track_batchsize: bool = envs.FASTVIDEO_LOG_BATCHSIZE_INTERVAL >= 0
track_batchsize: bool = False
last_logging_time: float = 0
forward_start_time: float = 0
# batchsize_logging_interval: float = envs.FASTVIDEO_LOG_BATCHSIZE_INTERVAL
batchsize_logging_interval: float = 1000
batchsize_forward_time: defaultdict = defaultdict(list)
#
@dataclass
class ForwardContext:
current_timestep: int
# TODO(will): check this arg
# copy from vllm_config.compilation_config.static_forward_context
# attn_layers: Dict[str, Any]
# TODO: extend to support per-layer dynamic forward context
attn_metadata: "AttentionMetadata" # set dynamically for each forward pass
forward_batch: Optional["ForwardBatch"] = None
_forward_context: Optional["ForwardContext"] = None
def get_forward_context() -> "ForwardContext":
"""Get the current forward context."""
assert _forward_context is not None, ("Forward context is not set. "
"Please use `set_forward_context` to set the forward context.")
return _forward_context
# TODO(will): finalize the interface
@contextmanager
def set_forward_context(current_timestep, attn_metadata, forward_batch: Optional["ForwardBatch"] = None):
"""A context manager that stores the current forward context,
can be attention metadata, etc.
Here we can inject common logic for every model forward pass.
"""
global forward_start_time
need_to_track_batchsize = track_batchsize and attn_metadata is not None
if need_to_track_batchsize:
forward_start_time = time.perf_counter()
global _forward_context
prev_context = _forward_context
_forward_context = ForwardContext(current_timestep=current_timestep,
attn_metadata=attn_metadata,
forward_batch=forward_batch)
try:
yield
finally:
global last_logging_time, batchsize_logging_interval
if need_to_track_batchsize:
if hasattr(attn_metadata, "num_prefill_tokens"):
# for v0 attention backends
batchsize = attn_metadata.num_prefill_tokens + \
attn_metadata.num_decode_tokens
else:
# for v1 attention backends
batchsize = attn_metadata.num_input_tokens
now = time.perf_counter()
# time measurement is in milliseconds
batchsize_forward_time[batchsize].append((now - forward_start_time) * 1000)
if now - last_logging_time > batchsize_logging_interval:
last_logging_time = now
forward_stats = []
for bs, times in batchsize_forward_time.items():
if len(times) <= 1:
# can be cudagraph / profiling run
continue
medium = torch.quantile(torch.tensor(times), q=0.5).item()
medium = round(medium, 2)
forward_stats.append((bs, len(times), medium))
forward_stats.sort(key=lambda x: x[1], reverse=True)
if forward_stats:
logger.info(("Batchsize forward time stats "
"(batchsize, count, median_time(ms)): %s"), forward_stats)
_forward_context = prev_context