The transformer and text encoder auto-quantize; the VAE stayed dense. VAEs are convolutional, so torchao int8 (Linear/2D-only) does not apply, but Float8DynamicActivationFloat8WeightConfig quantizes Conv2d/Conv3d weights with PerTensor granularity (auto-skipping convs whose channels are not a multiple of 16, so the 3-channel RGB head stays dense). New diffusion_vae_quant.py offers two schemes: fp8_dynamic (torchao conv compute fp8, cc>=8.9, resident) and fp8 (diffusers layerwise storage cast, any conv, survives offload); no int8 (no Conv3d int8 kernel). select_vae_quant_scheme walks (fp8_dynamic, fp8) with a live conv smoke probe, an offload gate, a per-family deny list, and a force_fp32 gate; the image + video loaders map unset vae_quant to auto, skip the vae_force_fp32 Wan families, and record the engaged scheme. Guards _align_vae_dtype to skip the img2img/inpaint re-cast when the VAE is quantized (its fp8 tensor subclasses reject .to(dtype=)). Verified on a B200: %16 Conv2d/Conv3d/Linear -> Float8Tensor, conv_out dense, forward runs.
379 lines
17 KiB
Python
379 lines
17 KiB
Python
# SPDX-License-Identifier: AGPL-3.0-only
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# Copyright 2026-present the Unsloth AI Inc. team. All rights reserved. See /studio/LICENSE.AGPL-3.0
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"""Unit tests for VAE quantisation (``diffusion_vae_quant.py``).
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Hermetic: torch + the diffusers / torchao casters are stubbed via ``sys.modules`` so
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gating, the conv filter, and the apply path run without a GPU, real diffusers, or real
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torchao. Mirrors tests/test_diffusion_precision.py's stubbing style.
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"""
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from __future__ import annotations
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import sys
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import types
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import pytest
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import core.inference.diffusion_vae_quant as vq
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from core.inference.diffusion_vae_quant import (
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VAE_QUANT_AUTO,
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VAE_QUANT_FP8,
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VAE_QUANT_FP8_DYNAMIC,
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_cast_vae_fp8,
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_cast_vae_fp8_dynamic,
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normalize_vae_quant,
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quantize_vae,
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select_vae_quant_scheme,
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vae_quant_supported,
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)
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def _target(*, device = "cuda", dtype = "bfloat16", cc = (10, 0)):
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return types.SimpleNamespace(device = device, dtype = dtype, _cc = cc)
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class _Weight:
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"""A stand-in for a conv / linear weight tensor: exposes ``.shape`` and ``.dim()``."""
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def __init__(self, shape):
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self.shape = shape
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def dim(self):
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return len(self.shape)
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def _stub_torch(monkeypatch, *, with_fp8 = True, cc = (10, 0)):
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torch = types.ModuleType("torch")
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torch.bfloat16 = "bfloat16"
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torch.float16 = "float16"
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if with_fp8:
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torch.float8_e4m3fn = "float8_e4m3fn"
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# The conv filter isinstance-checks nn.Linear / nn.Conv2d / nn.Conv3d, and the layerwise
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# caster reads torch.float8_e4m3fn, so the stub torch must expose both.
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torch.nn = types.SimpleNamespace(
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Linear = type("Linear", (), {}),
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Conv2d = type("Conv2d", (), {}),
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Conv3d = type("Conv3d", (), {}),
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)
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torch.cuda = types.SimpleNamespace(
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get_device_capability = lambda *a: cc,
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synchronize = lambda *a, **k: None,
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is_available = lambda: True,
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)
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monkeypatch.setitem(sys.modules, "torch", torch)
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return torch
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def _stub_torchao(monkeypatch, captured):
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# torchao's fp8_dynamic conv config + quantize_. Records the (config, filter_fn) so the
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# PerTensor granularity and the conv filter closure can be asserted.
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tq = types.ModuleType("torchao.quantization")
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tq.quantize_ = lambda module, config, filter_fn = None: captured.update(
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module = module, config = config, filter_fn = filter_fn
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)
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tq.Float8DynamicActivationFloat8WeightConfig = lambda granularity = None: ("fp8dyn", granularity)
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tq.PerTensor = lambda: "pertensor"
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monkeypatch.setitem(sys.modules, "torchao.quantization", tq)
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return tq
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def _stub_diffusers(monkeypatch, recorder):
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hooks = types.ModuleType("diffusers.hooks")
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casting = types.ModuleType("diffusers.hooks.layerwise_casting")
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casting.DEFAULT_SKIP_MODULES_PATTERN = ("norm",)
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hooks.apply_layerwise_casting = lambda module, **kw: recorder.append(("fp8", module, kw))
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monkeypatch.setitem(sys.modules, "diffusers.hooks", hooks)
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monkeypatch.setitem(sys.modules, "diffusers.hooks.layerwise_casting", casting)
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def _stub_capability(monkeypatch, cc):
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"""Stub the transformer module's ``_capability`` that select_vae_quant_scheme imports."""
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dtq = types.ModuleType("core.inference.diffusion_transformer_quant")
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dtq._capability = lambda: cc
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monkeypatch.setitem(sys.modules, "core.inference.diffusion_transformer_quant", dtq)
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return dtq
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def _allow_vae(monkeypatch, allowed):
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"""Force vae_quant_supported to accept only ``allowed`` (simulates the hardware gate)."""
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monkeypatch.setattr(vq, "vae_quant_supported", lambda target, mode: mode in allowed)
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# ── normalisation ─────────────────────────────────────────────────────────────
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def test_normalize_vae_quant():
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assert normalize_vae_quant(None) is None
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assert normalize_vae_quant("") is None
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assert normalize_vae_quant("none") is None
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# "off" disables (like the TE / transformer normalisers) -> dense.
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assert normalize_vae_quant("off") is None
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# "auto" passes through for select_vae_quant_scheme to resolve.
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assert normalize_vae_quant("AUTO") == VAE_QUANT_AUTO
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assert normalize_vae_quant("FP8") == VAE_QUANT_FP8
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# Hyphens fold to underscores so "fp8-dynamic" is accepted.
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assert normalize_vae_quant("FP8-Dynamic") == VAE_QUANT_FP8_DYNAMIC
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# int8 / nvfp4 have no VAE scheme -> rejected.
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with pytest.raises(ValueError):
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normalize_vae_quant("int8")
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with pytest.raises(ValueError):
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normalize_vae_quant("nvfp4")
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# ── gating ────────────────────────────────────────────────────────────────────
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def test_vae_quant_supported_fp8_requires_cuda_bf16_and_fp8(monkeypatch):
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_stub_torch(monkeypatch, with_fp8 = True, cc = (8, 9))
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assert vae_quant_supported(_target(), VAE_QUANT_FP8) is True
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assert vae_quant_supported(_target(device = "cpu"), VAE_QUANT_FP8) is False
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assert vae_quant_supported(_target(dtype = "float16"), VAE_QUANT_FP8) is False
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# No fp8 dtype at all -> unsupported.
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_stub_torch(monkeypatch, with_fp8 = False, cc = (8, 9))
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assert vae_quant_supported(_target(), VAE_QUANT_FP8) is False
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def test_vae_quant_supported_fp8_dynamic_requires_sm89(monkeypatch):
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# Compute fp8 conv (torch._scaled_mm) needs fp8-GEMM silicon: Ada sm_89+ / Hopper / Blackwell.
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_stub_torch(monkeypatch, cc = (8, 9))
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assert vae_quant_supported(_target(), VAE_QUANT_FP8_DYNAMIC) is True
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_stub_torch(monkeypatch, cc = (9, 0))
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assert vae_quant_supported(_target(), VAE_QUANT_FP8_DYNAMIC) is True
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# Ampere (8.0) has no fp8 GEMM.
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_stub_torch(monkeypatch, cc = (8, 0))
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assert vae_quant_supported(_target(), VAE_QUANT_FP8_DYNAMIC) is False
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# ── auto ladder (select_vae_quant_scheme) ───────────────────────────────────────
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def test_select_datacenter_prefers_fp8_dynamic(monkeypatch):
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# Data-center fp8-GEMM silicon with a passing conv probe: fp8_dynamic leads the ladder.
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_stub_capability(monkeypatch, (10, 0))
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_allow_vae(monkeypatch, {VAE_QUANT_FP8_DYNAMIC, VAE_QUANT_FP8})
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monkeypatch.setattr(vq, "_vae_fp8_dynamic_probe", lambda device: True)
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assert select_vae_quant_scheme(_target(), "auto", family = "flux.1") == VAE_QUANT_FP8_DYNAMIC
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def test_select_offload_uses_layerwise_fp8(monkeypatch):
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# Under offload the torchao fp8_dynamic mode (rejects Module.to()) is skipped BEFORE the
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# probe -> layerwise fp8. The probe must not even run.
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_stub_capability(monkeypatch, (10, 0))
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_allow_vae(monkeypatch, {VAE_QUANT_FP8_DYNAMIC, VAE_QUANT_FP8})
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monkeypatch.setattr(
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vq, "_vae_fp8_dynamic_probe", lambda device: pytest.fail("probe must not run under offload")
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)
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assert (
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select_vae_quant_scheme(_target(), "auto", offload_active = True) == VAE_QUANT_FP8
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)
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def test_select_force_fp32_stays_dense(monkeypatch):
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# A force-fp32 (Wan) family never quantises, for auto or an explicit request.
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_stub_capability(monkeypatch, (10, 0))
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_allow_vae(monkeypatch, {VAE_QUANT_FP8_DYNAMIC, VAE_QUANT_FP8})
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assert select_vae_quant_scheme(_target(), "auto", force_fp32 = True) is None
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assert select_vae_quant_scheme(_target(), "fp8", force_fp32 = True) is None
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def test_select_family_deny_skips_scheme(monkeypatch):
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_stub_capability(monkeypatch, (10, 0))
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_allow_vae(monkeypatch, {VAE_QUANT_FP8_DYNAMIC, VAE_QUANT_FP8})
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monkeypatch.setattr(vq, "_vae_fp8_dynamic_probe", lambda device: True)
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monkeypatch.setattr(
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vq, "_VAE_FAMILY_SCHEME_DENY", {"badfam": frozenset({VAE_QUANT_FP8_DYNAMIC})}
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)
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# fp8_dynamic denied for this family -> falls to layerwise fp8.
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assert select_vae_quant_scheme(_target(), "auto", family = "badfam") == VAE_QUANT_FP8
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def test_select_no_capability_is_none(monkeypatch):
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_stub_capability(monkeypatch, None)
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_allow_vae(monkeypatch, {VAE_QUANT_FP8_DYNAMIC, VAE_QUANT_FP8})
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assert select_vae_quant_scheme(_target(), "auto") is None
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def test_select_support_gate_falls_to_fp8(monkeypatch):
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# fp8_dynamic hardware-unsupported (only fp8 allowed) -> layerwise fp8.
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_stub_capability(monkeypatch, (8, 9))
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_allow_vae(monkeypatch, {VAE_QUANT_FP8})
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monkeypatch.setattr(vq, "_vae_fp8_dynamic_probe", lambda device: True)
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assert select_vae_quant_scheme(_target(), "auto") == VAE_QUANT_FP8
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def test_select_smoke_failure_falls_to_fp8(monkeypatch):
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# fp8_dynamic is hardware-supported but its conv probe fails -> layerwise fp8.
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_stub_capability(monkeypatch, (10, 0))
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_allow_vae(monkeypatch, {VAE_QUANT_FP8_DYNAMIC, VAE_QUANT_FP8})
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monkeypatch.setattr(vq, "_vae_fp8_dynamic_probe", lambda device: False)
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assert select_vae_quant_scheme(_target(), "auto") == VAE_QUANT_FP8
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def test_select_explicit_passthrough(monkeypatch):
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# An explicit request is returned as-is (quantize_vae re-gates it); no ladder walk,
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# so no transformer-module stub is needed.
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assert select_vae_quant_scheme(_target(), "fp8") == VAE_QUANT_FP8
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assert select_vae_quant_scheme(_target(), "fp8_dynamic") == VAE_QUANT_FP8_DYNAMIC
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assert select_vae_quant_scheme(_target(), None) is None
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assert select_vae_quant_scheme(_target(), "none") is None
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def test_select_explicit_family_deny_returns_none(monkeypatch):
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monkeypatch.setattr(vq, "_VAE_FAMILY_SCHEME_DENY", {"badfam": frozenset({VAE_QUANT_FP8})})
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assert select_vae_quant_scheme(_target(), "fp8", family = "badfam") is None
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# ── conv-aware filter (_cast_vae_fp8_dynamic) ───────────────────────────────────
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def test_fp8_dynamic_conv_filter(monkeypatch):
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# The real filter closure the PerTensor fp8 conv config receives: %16-channel Conv2d/Conv3d
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# and Linear quantise; off-%16 channels and the conv_out / norm_out head stay dense.
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torch = _stub_torch(monkeypatch)
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captured: dict = {}
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_stub_torchao(monkeypatch, captured)
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_cast_vae_fp8_dynamic(object(), _target())
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# PerTensor granularity (NOT the DiT's per-row) is what the config was built with.
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assert captured["config"] == ("fp8dyn", "pertensor")
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ff = captured["filter_fn"]
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nn = torch.nn
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def _mod(cls, shape):
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m = cls()
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m.weight = _Weight(shape)
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return m
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# Conv2d (4D) / Conv3d (5D) with both channel dims a multiple of 16 quantise.
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assert ff(_mod(nn.Conv2d, (128, 128, 3, 3)), "decoder.up.0.resnets.0.conv1") is True
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assert ff(_mod(nn.Conv3d, (64, 64, 3, 3, 3)), "decoder.mid_block.conv3d") is True
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# nn.Linear (mid-block attention projections) also quantise.
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assert ff(_mod(nn.Linear, (512, 512)), "decoder.mid_block.attentions.0.to_q") is True
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# Channels not a multiple of 16 excluded (torchao would skip them regardless): the RGB
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# in/out head (C=3) and any off-16 dim.
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assert ff(_mod(nn.Conv2d, (128, 3, 3, 3)), "encoder.conv_in") is False
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assert ff(_mod(nn.Conv2d, (24, 128, 3, 3)), "decoder.up.1.upsamplers.0.conv") is False
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# conv_out / proj_out / norm_out excluded by NAME even with %16 channels.
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assert ff(_mod(nn.Conv2d, (16, 128, 3, 3)), "decoder.conv_out") is False
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assert ff(_mod(nn.Conv2d, (128, 128, 3, 3)), "decoder.conv_norm_out") is False
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assert ff(_mod(nn.Conv2d, (128, 128, 3, 3)), "decoder.norm_out.conv") is False
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assert ff(_mod(nn.Linear, (512, 512)), "decoder.proj_out") is False
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# A non-conv/linear module (e.g. a GroupNorm) is excluded outright.
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class _GroupNorm:
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pass
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gn = _GroupNorm()
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gn.weight = _Weight((128,))
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assert ff(gn, "decoder.mid_block.resnets.0.norm1") is False
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# A weight with dim() < 2 (a 1D param) is excluded.
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assert ff(_mod(nn.Conv2d, (128,)), "decoder.some.bias_only") is False
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def test_cast_vae_fp8_layerwise_skips_head_and_norms(monkeypatch):
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# The layerwise storage cast passes the decoder head + norm tokens through to diffusers'
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# skip_modules_pattern (on top of the diffusers default), so they stay dense.
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_stub_torch(monkeypatch)
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recorder: list = []
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_stub_diffusers(monkeypatch, recorder)
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vae = object()
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_cast_vae_fp8(vae, _target())
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assert len(recorder) == 1
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_, mod, kw = recorder[0]
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assert mod is vae
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assert kw["storage_dtype"] == "float8_e4m3fn"
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assert kw["compute_dtype"] == "bfloat16"
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skip = kw["skip_modules_pattern"]
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# The diffusers default is preserved and the keep-dense tokens are appended.
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assert "norm" in skip
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for tok in ("conv_out", "proj_out", "conv_norm_out", "norm_out"):
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assert tok in skip
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# ── apply (quantize_vae) ────────────────────────────────────────────────────────
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def test_quantize_vae_disabled_returns_none(monkeypatch):
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pipe = types.SimpleNamespace(vae = object())
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assert quantize_vae(pipe, _target(), mode = None) is None
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assert quantize_vae(pipe, _target(), mode = "none") is None
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def test_quantize_vae_force_fp32_stays_dense(monkeypatch):
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# A force-fp32 (Wan) family never casts, for an explicit scheme or auto.
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_stub_torch(monkeypatch, cc = (10, 0))
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monkeypatch.setattr(vq, "_cast_vae_fp8_dynamic", lambda v, t: pytest.fail("must not cast"))
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monkeypatch.setattr(vq, "_cast_vae_fp8", lambda v, t: pytest.fail("must not cast"))
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pipe = types.SimpleNamespace(vae = object())
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assert quantize_vae(pipe, _target(), mode = "fp8", force_fp32 = True) is None
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assert quantize_vae(pipe, _target(), mode = "auto", force_fp32 = True) is None
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def test_quantize_vae_offload_skips_fp8_dynamic(monkeypatch):
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# Explicit fp8_dynamic under offload is skipped (torchao tensors reject Module.to());
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# layerwise fp8 still engages.
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_stub_torch(monkeypatch, cc = (10, 0))
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_allow_vae(monkeypatch, {VAE_QUANT_FP8_DYNAMIC, VAE_QUANT_FP8})
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monkeypatch.setattr(
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vq, "_cast_vae_fp8_dynamic", lambda v, t: pytest.fail("torchao must not run under offload")
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)
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pipe = types.SimpleNamespace(vae = object())
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assert quantize_vae(pipe, _target(), mode = "fp8_dynamic", offload_active = True) is None
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fp8_calls: list = []
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monkeypatch.setattr(vq, "_cast_vae_fp8", lambda v, t: fp8_calls.append(v))
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assert quantize_vae(pipe, _target(), mode = "fp8", offload_active = True) == VAE_QUANT_FP8
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assert len(fp8_calls) == 1
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def test_quantize_vae_unsupported_hw_is_noop(monkeypatch):
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# An explicit scheme on hardware that does not support it applies nothing.
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_stub_torch(monkeypatch, cc = (8, 0))
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_allow_vae(monkeypatch, set())
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monkeypatch.setattr(vq, "_cast_vae_fp8", lambda v, t: pytest.fail("must not cast"))
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pipe = types.SimpleNamespace(vae = object())
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assert quantize_vae(pipe, _target(), mode = "fp8") is None
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def test_quantize_vae_none_vae_is_noop(monkeypatch):
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# A pipeline with no VAE attribute is a best-effort no-op even when the mode is supported.
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_stub_torch(monkeypatch, cc = (10, 0))
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_allow_vae(monkeypatch, {VAE_QUANT_FP8})
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pipe = types.SimpleNamespace() # no .vae
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assert quantize_vae(pipe, _target(), mode = "fp8") is None
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def test_quantize_vae_explicit_fp8_applies(monkeypatch):
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_stub_torch(monkeypatch, cc = (10, 0))
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_allow_vae(monkeypatch, {VAE_QUANT_FP8})
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calls: list = []
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monkeypatch.setattr(vq, "_cast_vae_fp8", lambda v, t: calls.append(v))
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vae = object()
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pipe = types.SimpleNamespace(vae = vae)
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assert quantize_vae(pipe, _target(), mode = "fp8") == VAE_QUANT_FP8
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assert calls == [vae]
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def test_quantize_vae_tolerates_caster_failure(monkeypatch):
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# The caster raising leaves the VAE dense (best-effort) -> None.
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_stub_torch(monkeypatch, cc = (10, 0))
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_allow_vae(monkeypatch, {VAE_QUANT_FP8})
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def _boom(v, t):
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raise RuntimeError("fp8 unsupported for this layer")
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monkeypatch.setattr(vq, "_cast_vae_fp8", _boom)
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pipe = types.SimpleNamespace(vae = object())
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assert quantize_vae(pipe, _target(), mode = "fp8") is None
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def test_quantize_vae_auto_resolves_and_applies(monkeypatch):
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# End-to-end: mode="auto" resolves via the ladder then applies the resolved caster.
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_stub_torch(monkeypatch, cc = (10, 0))
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_stub_capability(monkeypatch, (10, 0))
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_allow_vae(monkeypatch, {VAE_QUANT_FP8_DYNAMIC, VAE_QUANT_FP8})
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monkeypatch.setattr(vq, "_vae_fp8_dynamic_probe", lambda device: True)
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calls: list = []
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monkeypatch.setattr(vq, "_cast_vae_fp8_dynamic", lambda v, t: calls.append(v))
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vae = object()
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pipe = types.SimpleNamespace(vae = vae)
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assert quantize_vae(pipe, _target(), mode = "auto", family = "flux.1") == VAE_QUANT_FP8_DYNAMIC
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assert calls == [vae]
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