Files
hao-ai-lab-FastVideo/v2/models/reward/loop.py
T
SolitaryThinker 9489c6c1dd [feat] Five more stress tests: LTX-2 A/V, weight-sync, served reward, cache-dit, nested workflows
The remaining design_v3 probes (all except 8b speculative decoding). All fit with no new runtime
primitive (148 tests pass).

#6 LTX-2 joint audio+video (§9.11) — LTX-2 declared an audio_vae required_for t2vs but never used
   it; now a single 2-stage denoise carries a synchronized audio latent (conditioned on video),
   applies per-modality CFG (guidance_per_modality), and decodes via video VAE + audio VAE → video +
   audio. Gated on requesting audio, so the T2V path is byte-identical (existing tests untouched).
   ToyAudioVAE; build_ltx2_av_program. 5 tests.

#4 Live weight-sync under in-flight serving (§9.14) — WeightSyncController makes the freeze → drain →
   transfer → bump version + invalidate → resume lifecycle explicit. Tests: a mid-flight swap corrupts
   (the hazard); draining first leaves the in-flight request bit-identical to baseline while a
   post-sync request reflects new weights; transformer-only sync, so the frozen text-encoder cache
   survives. The RL flywheel's hardest correctness. 3 tests.

#5 Reward-model-as-a-served-card (§9.15) — a reward model is a card (scorer + a score loop emitting
   REWARD_BATCH units); ServedRewardScorer drop-in-replaces the numpy scorer so any RL method becomes
   RLHF/RLAIF with no method change. ToyRewardModel; models/reward/. 4 tests.

#7 Content-adaptive control flow (§9.12) — CacheDiTDenoiseLoop (isolated WanDenoiseLoop subclass)
   reuses the cached velocity when predictions barely change (cache-dit skip) and early-exits on
   convergence — variable step count; interleave parity holds across ragged loops. models/adaptive/. 4 tests.

#8a Nested workflows (§9.13) — a workflow stage can invoke another workflow (engine.run routes ids);
   requires/validate recurse; cycles caught at registration + a run-time guard (engine._wf_running).
   build_t2i_i2v_extend_workflow. 5 tests.

designv4 §9.11–§9.15 + falsifier/layout/closing updates (148 tests, 25 files). Also removed a
pre-existing unused import in ltx2/loop.py.
2026-07-04 17:15:34 +00:00

65 lines
2.7 KiB
Python

"""RewardLoop — a served reward model scoring samples as ``REWARD_BATCH`` WorkUnits (design_v3 §10).
The reward in RL is computed by a *model* (PickScore/CLIP/a VLM verifier), not a heuristic. This loop
makes that a first-class part of the runtime: it reads a batch of K rollout media from a slot and emits
``REWARD_BATCH`` work units (chunked) that score them through the engine — so reward compute is admitted,
priced, and interleavable exactly like a denoise step or an AR token. A GRPO group's K samples score in
one (or a few) batched units — the homogeneous-batch win the scheduler likes.
"""
from __future__ import annotations
from ..._enums import WorkUnitKind
from ...loop.contracts import (
Done,
LoopResult,
LoopState,
ResourceRequest,
ShapeSignature,
StepResult,
WorkPlan,
)
class RewardLoop:
def __init__(self, *, loop_id, scorer_id="scorer", cost, media_slot="media", batch=4):
self.loop_id = loop_id
self.scorer_id = scorer_id
self.cost = cost
self.media_slot = media_slot
self.batch = batch
def init(self, req, model, ctx) -> LoopState:
media = list(ctx.slots.get(self.media_slot) or [])
st = LoopState(loop_id=self.loop_id, instance_id=model.card.model_id,
request_id=req.request_id, profile=ctx.profile)
st.scratch["batches"] = [media[i:i + self.batch] for i in range(0, len(media), self.batch)] or [[]]
st.scratch["scores"] = []
return st
def next(self, st: LoopState):
i = st.step_idx
batches = st.scratch["batches"]
if i >= len(batches):
return Done()
chunk, sid = batches[i], self.scorer_id
def run(model, override=None):
scorer = model.component(sid)
return StepResult(output={"scores": [float(scorer.score(m)) for m in chunk], "i": i})
return WorkPlan(
loop_id=self.loop_id, instance_id=st.instance_id, kind=WorkUnitKind.REWARD_BATCH,
shape_sig=ShapeSignature(WorkUnitKind.REWARD_BATCH, dims=(len(chunk),)),
resources=ResourceRequest(compute_seconds=self.cost.predict(len(chunk)),
resident_bytes=64 * max(1, len(chunk)), peak_activation_bytes=64),
payload={"reward_batch": i}, run=run, label=f"reward.batch{i}")
def advance(self, st: LoopState, result: StepResult) -> LoopState:
st.scratch["scores"].extend(result.output["scores"])
st.step_idx += 1
return st
def finalize(self, st: LoopState) -> LoopResult:
return LoopResult(outputs={"rewards": list(st.scratch["scores"])},
metrics={"reward_batches": float(st.step_idx)})