unsloth/studio/backend/tests/test_diffusion_speed.py
2026-06-30 22:34:29 +00:00

276 lines
10 KiB
Python

# SPDX-License-Identifier: AGPL-3.0-only
# Copyright 2026-present the Unsloth AI Inc. team. All rights reserved. See /studio/LICENSE.AGPL-3.0
"""Unit tests for the opt-in diffusion speed layer (``diffusion_speed.py``).
Hermetic: torch is stubbed via ``sys.modules`` only where a path needs it, so the
gating logic and the best-effort applier run without a GPU or real diffusers.
"""
from __future__ import annotations
import sys
import types
import pytest
from core.inference.diffusion_speed import (
SPEED_DEFAULT,
SPEED_MAX,
SPEED_OFF,
apply_speed_optims,
compile_eligible,
normalize_speed_mode,
resolve_speed_mode,
restore_backend_flags,
snapshot_backend_flags,
)
def _target(
*,
device = "cuda",
dtype = "bfloat16",
compile_ok = True,
):
return types.SimpleNamespace(
device = device,
dtype = dtype,
supports_default_torch_compile = compile_ok,
)
def _family(*, compile_ok = True):
return types.SimpleNamespace(supports_torch_compile = compile_ok)
def _stub_torch(monkeypatch):
torch = types.ModuleType("torch")
torch.bfloat16 = "bfloat16" # _is_bfloat16 compares by identity then str fallback
torch.channels_last = "channels_last"
torch.backends = types.SimpleNamespace(
cuda = types.SimpleNamespace(matmul = types.SimpleNamespace(allow_tf32 = False)),
cudnn = types.SimpleNamespace(allow_tf32 = False, benchmark = False),
)
monkeypatch.setitem(sys.modules, "torch", torch)
return torch
# ── normalisation ─────────────────────────────────────────────────────────────
def test_normalize_speed_mode():
assert normalize_speed_mode(None) == SPEED_OFF
assert normalize_speed_mode("") == SPEED_OFF
assert normalize_speed_mode("MAX") == SPEED_MAX
with pytest.raises(ValueError):
normalize_speed_mode("ludicrous")
def test_resolve_speed_mode_gguf_auto_default():
# Unset (None) -> default for GGUF (near-lossless), off for dense.
assert resolve_speed_mode(None, is_gguf = True) == SPEED_DEFAULT
assert resolve_speed_mode(None, is_gguf = False) == SPEED_OFF
# An explicit value is honored verbatim, including an explicit opt-out to off.
assert resolve_speed_mode("off", is_gguf = True) == SPEED_OFF
assert resolve_speed_mode("max", is_gguf = True) == SPEED_MAX
assert resolve_speed_mode("max", is_gguf = False) == SPEED_MAX
# ── compile gating ────────────────────────────────────────────────────────────
def test_compile_eligible_requires_bf16_cuda_friendly(monkeypatch):
_stub_torch(monkeypatch)
# The happy path: bf16, CUDA, compile-friendly family.
assert compile_eligible(_target(), is_gguf = False, family = _family()) is True
# GGUF is now compile-eligible too (measured ~2.3x, PSNR ~37 dB vs eager).
assert compile_eligible(_target(), is_gguf = True, family = _family()) is True
# fp16 (non-bf16) is excluded.
assert compile_eligible(_target(dtype = "float16"), is_gguf = False, family = _family()) is False
# A family flagged not compile-friendly is excluded.
assert compile_eligible(_target(), is_gguf = False, family = _family(compile_ok = False)) is False
# No compile support (e.g. XPU/MPS) is excluded.
assert compile_eligible(_target(compile_ok = False), is_gguf = False, family = _family()) is False
# ── backend-flag snapshot / restore (TF32 / cudnn.benchmark leak guard) ────────
def test_snapshot_restore_backend_flags(monkeypatch):
torch = _stub_torch(monkeypatch)
snap = snapshot_backend_flags()
assert snap == {"matmul_tf32": False, "cudnn_tf32": False, "cudnn_benchmark": False}
# An opt-in max run flips the globals on...
torch.backends.cuda.matmul.allow_tf32 = True
torch.backends.cudnn.allow_tf32 = True
torch.backends.cudnn.benchmark = True
# ...and restore puts them back, so a later `off` load is bit-identical again.
restore_backend_flags(snap)
assert torch.backends.cuda.matmul.allow_tf32 is False
assert torch.backends.cudnn.allow_tf32 is False
assert torch.backends.cudnn.benchmark is False
def test_restore_backend_flags_tolerates_none():
restore_backend_flags(None) # no torch needed, no-op
def test_snapshot_partial_when_some_backends_missing(monkeypatch):
# A build/platform without cuda.matmul (e.g. CPU/MPS) must still snapshot + restore the
# flags it does have, rather than skipping the whole snapshot on one missing attribute.
torch = types.ModuleType("torch")
torch.backends = types.SimpleNamespace(
cuda = types.SimpleNamespace(), # no .matmul
cudnn = types.SimpleNamespace(benchmark = True), # no .allow_tf32
)
monkeypatch.setitem(sys.modules, "torch", torch)
snap = snapshot_backend_flags()
assert snap == {"cudnn_benchmark": True}
torch.backends.cudnn.benchmark = False
restore_backend_flags(snap)
assert torch.backends.cudnn.benchmark is True
def test_restore_is_independent_per_flag(monkeypatch):
# A read-only / failing attribute must not abort restoring the remaining flags.
torch = _stub_torch(monkeypatch)
class _NoMatmulSet:
@property
def allow_tf32(self):
return False
@allow_tf32.setter
def allow_tf32(self, value):
raise RuntimeError("read-only on this build")
torch.backends.cuda.matmul = _NoMatmulSet()
snap = {"matmul_tf32": False, "cudnn_tf32": False, "cudnn_benchmark": False}
torch.backends.cudnn.benchmark = True
restore_backend_flags(snap) # matmul setter raises, cudnn still restored
assert torch.backends.cudnn.benchmark is False
# ── applier ───────────────────────────────────────────────────────────────────
class _Pipe:
def __init__(
self,
*,
with_compile = False,
with_fuse = False,
) -> None:
self.vae = types.SimpleNamespace(mem_format = None, to = self._vae_to)
self.transformer = types.SimpleNamespace()
if with_compile:
self.transformer.compile_repeated_blocks = self._compile
if with_fuse:
self.fuse_qkv_projections = self._fuse
self.compiled = False
self.fused = False
def _vae_to(self, *, memory_format):
self.vae.mem_format = memory_format
def _compile(self, **kwargs):
self.compiled = True
self.compile_kwargs = kwargs
def _fuse(self):
self.fused = True
def test_speed_off_applies_nothing(monkeypatch):
torch = _stub_torch(monkeypatch)
pipe = _Pipe(with_compile = True, with_fuse = True)
applied = apply_speed_optims(
pipe, _target(), is_gguf = False, family = _family(), speed_mode = SPEED_OFF
)
assert applied == {
"channels_last": False,
"cudnn_benchmark": False,
"tf32": False,
"fused_qkv": False,
"compiled": False,
}
assert pipe.vae.mem_format is None and pipe.compiled is False
# off must not touch any process-wide flag (bit-identical reference path).
assert torch.backends.cudnn.benchmark is False
def test_speed_default_channels_last_compile_and_cudnn_benchmark(monkeypatch):
torch = _stub_torch(monkeypatch)
pipe = _Pipe(with_compile = True)
applied = apply_speed_optims(
pipe, _target(), is_gguf = False, family = _family(), speed_mode = SPEED_DEFAULT
)
assert applied["channels_last"] is True and pipe.vae.mem_format == torch.channels_last
assert applied["compiled"] is True and pipe.compiled is True
# default compiles with dynamic=True and no autotune mode (fast cold start,
# resolution-robust, sidesteps the CUDA-graph crash).
assert pipe.compile_kwargs == {"fullgraph": True, "dynamic": True}
# default also autotunes the VAE convs but does NOT flip TF32 or fuse QKV.
assert applied["cudnn_benchmark"] is True and torch.backends.cudnn.benchmark is True
assert applied["tf32"] is False and applied["fused_qkv"] is False
def test_speed_default_compiles_gguf(monkeypatch):
_stub_torch(monkeypatch)
pipe = _Pipe(with_compile = True)
applied = apply_speed_optims(
pipe, _target(), is_gguf = True, family = _family(), speed_mode = SPEED_DEFAULT
)
assert applied["channels_last"] is True
# GGUF now compiles (the big near-lossless win).
assert applied["compiled"] is True and pipe.compiled is True
def test_speed_default_cudnn_benchmark_only_on_cuda(monkeypatch):
_stub_torch(monkeypatch)
pipe = _Pipe(with_compile = True)
applied = apply_speed_optims(
pipe,
_target(device = "mps", compile_ok = False),
is_gguf = True,
family = _family(),
speed_mode = SPEED_DEFAULT,
)
assert applied["cudnn_benchmark"] is False # not CUDA -> no autotune flip
def test_speed_max_enables_tf32_and_fused_qkv(monkeypatch):
torch = _stub_torch(monkeypatch)
pipe = _Pipe(with_compile = True, with_fuse = True)
applied = apply_speed_optims(
pipe, _target(), is_gguf = False, family = _family(), speed_mode = SPEED_MAX
)
assert applied["tf32"] is True and torch.backends.cuda.matmul.allow_tf32 is True
assert applied["fused_qkv"] is True and pipe.fused is True
# max opts into autotuned kernels (static shapes); CUDA-graph modes are avoided.
assert pipe.compile_kwargs["mode"] == "max-autotune-no-cudagraphs"
assert pipe.compile_kwargs["dynamic"] is False
def test_speed_max_tf32_only_on_cuda(monkeypatch):
_stub_torch(monkeypatch)
pipe = _Pipe()
applied = apply_speed_optims(
pipe,
_target(device = "mps", compile_ok = False),
is_gguf = True,
family = _family(),
speed_mode = SPEED_MAX,
)
assert applied["tf32"] is False # not CUDA -> no TF32
def test_apply_tolerates_missing_optims(monkeypatch):
_stub_torch(monkeypatch)
# A bare pipe (no vae.to, no compile, no fuse) must not crash.
bare = types.SimpleNamespace(vae = None, transformer = types.SimpleNamespace())
applied = apply_speed_optims(
bare, _target(), is_gguf = False, family = _family(), speed_mode = SPEED_MAX
)
assert applied["channels_last"] is False and applied["fused_qkv"] is False