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[Diffusion] Add loader-owned host-weight plans for DLO (TP=1) (#6213)

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Signed-off-by: Hongsheng Liu <liuhongsheng4@huawei.com>
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Hongsheng Liu authored and GitHub committed 2026-08-16 11:02:38 +08:00
1 parent 3875f8ded4
commit 9d2bb23ff6
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tests/diffusion/offloader/test_distributed_layerwise_backend.py
+515 -80
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@@ -18,6 +18,11 @@ from torch import nn
from torch.distributed.tensor import DeviceMesh, DTensor, Replicate
import vllm_omni.diffusion.offloader.distributed_layerwise_backend as dist_backend_module
from vllm_omni.diffusion.model_loader.host_weight_plan import (
HostWeightPlan,
TensorBinding,
build_checkpoint_mmap_plan,
)
from vllm_omni.diffusion.offloader.base import OffloadConfig, OffloadStrategy
from vllm_omni.diffusion.offloader.block_discovery import (
get_blocks_attr_names,
@@ -30,7 +35,10 @@ from vllm_omni.diffusion.offloader.distributed_layerwise_backend import (
PinnedResidentLayerGroup,
)
from vllm_omni.diffusion.offloader.module_residency import PinnedModuleStager
from vllm_omni.diffusion.offloader.offload_plan import OffloadPlan, get_offload_plan
from vllm_omni.diffusion.offloader.offload_plan import (
OffloadPlan,
get_offload_plan,
)
from vllm_omni.platforms import current_omni_platform
pytestmark = [pytest.mark.diffusion, pytest.mark.cpu, pytest.mark.core_model]
@@ -48,6 +56,9 @@ class DummyEvent:
def record(self, _stream) -> None:
return None
def synchronize(self) -> None:
return None
@contextmanager
def dummy_stream(_stream):
@@ -351,8 +362,9 @@ class TestDistributedLayerwiseOffloadHook:
block.weight = nn.Parameter(torch.zeros(4, dtype=torch.float32))
next_block = nn.Module()
next_block.weight = nn.Parameter(torch.arange(4, dtype=torch.float32))
next_block.weight.mmap_weight_transform = lambda tensor: tensor.flip(0)
next_block.weight.mmap_weight_transform_pending = True
def transform(tensor):
return tensor.flip(0)
hook = DistributedLayerwiseOffloadHook(
next_block=next_block,
@@ -361,17 +373,17 @@ class TestDistributedLayerwiseOffloadHook:
dp_size=2,
rank=0,
pin_memory=False,
tensor_transforms={id(next_block.weight): transform},
)
hook.initialize_hook(block)
assert torch.equal(hook.cpu_shards[torch.float32], torch.tensor([3.0, 2.0]))
def test_regular_loader_weight_does_not_reapply_mmap_transform(self, dist_group, patched_offload_runtime):
def test_transform_is_not_applied_without_a_loader_plan(self, dist_group, patched_offload_runtime):
block = nn.Module()
block.weight = nn.Parameter(torch.zeros(4, dtype=torch.float32))
next_block = nn.Module()
next_block.weight = nn.Parameter(torch.arange(4, dtype=torch.float32))
next_block.weight.mmap_weight_transform = lambda tensor: tensor.flip(0)
hook = DistributedLayerwiseOffloadHook(
next_block=next_block,
@@ -385,6 +397,82 @@ class TestDistributedLayerwiseOffloadHook:
assert torch.equal(hook.cpu_shards[torch.float32], torch.tensor([0.0, 1.0]))
def test_rank_local_mmap_retains_source_and_uses_staging(self, dist_group, patched_offload_runtime):
current_block = nn.Linear(2, 2, bias=False)
next_block = nn.Linear(2, 2, bias=False)
next_block.weight.data.copy_(torch.arange(4, dtype=torch.float32).view(2, 2))
source_storage = next_block.weight.untyped_storage().data_ptr()
def transform(tensor):
return tensor.t()
hook = DistributedLayerwiseOffloadHook(
next_block=next_block,
device=torch.device("cpu"),
dp_group=None,
dp_size=1,
rank=0,
pin_memory=False,
rank_local_mmap=True,
tensor_transforms={id(next_block.weight): transform},
)
hook.initialize_hook(current_block)
source = hook.cpu_sources[torch.float32][0]["tensor"]
assert source.untyped_storage().data_ptr() == source_storage
assert hook.cpu_shards == {}
assert next_block.weight.numel() == 0
hook.cpu_staging_buffers = [
{torch.float32: torch.empty(4)},
{torch.float32: torch.empty(4)},
]
hook.prefetch_layer(slot=0, non_blocking=False)
assert torch.equal(
next_block.weight,
torch.tensor([[0.0, 2.0], [1.0, 3.0]]),
)
assert next_block.weight.stride() == (1, 2)
assert torch.equal(source, torch.arange(4, dtype=torch.float32).view(2, 2))
def test_rank_local_mmap_staging_is_bounded_by_largest_block(self, patched_offload_runtime):
hooks = []
for size in (4, 9):
current_block = nn.Linear(1, 1, bias=False)
next_block = nn.Module()
next_block.weight = nn.Parameter(torch.arange(size, dtype=torch.float32))
hook = DistributedLayerwiseOffloadHook(
next_block=next_block,
device=torch.device("cpu"),
dp_group=None,
dp_size=1,
rank=0,
pin_memory=False,
shared_buffers=[None, None],
rank_local_mmap=True,
)
hook.initialize_hook(current_block)
hooks.append(hook)
resident_block = nn.Module()
resident_block.weight = nn.Parameter(torch.arange(12, dtype=torch.float32))
resident_group = PinnedResidentLayerGroup(
[resident_block],
device=torch.device("cpu"),
copy_stream=DummyStream(),
pin_memory=False,
rank_local_mmap=True,
)
staging = DistributedLayerwiseOffloadBackend._allocate_shared_cpu_staging_buffers(
hooks,
resident_group,
)
assert len(staging) == 2
assert staging[0][torch.float32].numel() == 12
assert staging[1][torch.float32].numel() == 12
class TestPinnedResidentLayerGroup:
def test_load_offload_reuses_pinned_master_weights(self, patched_offload_runtime):
@@ -439,23 +527,41 @@ class TestPinnedResidentLayerGroup:
assert block.weight.stride() == expected_stride
group.offload()
def test_mmap_loader_attrs_survive_to_empty_parameter_replacement(self):
module = nn.Linear(2, 2, bias=False)
def test_rank_local_mmap_resident_layers_retain_sources(self, patched_offload_runtime):
blocks = [nn.Linear(2, 2, bias=False) for _ in range(3)]
expected = []
source_storage = []
for index, block in enumerate(blocks):
block.weight.data.fill_(index + 1)
expected.append(block.weight.detach().clone())
source_storage.append(block.weight.untyped_storage().data_ptr())
def transform(tensor):
return tensor.flip(0)
group = PinnedResidentLayerGroup(
blocks,
device=torch.device("cpu"),
copy_stream=DummyStream(),
pin_memory=False,
rank_local_mmap=True,
)
module.weight.mmap_weight_transform = transform
for index, state in enumerate(group._states):
source = state["cpu_sources"][torch.float32][0]["tensor"]
assert source.untyped_storage().data_ptr() == source_storage[index]
assert state["cpu_shards"] == {}
assert len(group._cpu_staging_buffers) == 2
backend = object.__new__(DistributedLayerwiseOffloadBackend)
backend._remember_mmap_param_attrs(module)
module.to_empty(device="meta")
group.load()
for block, weight in zip(blocks, expected):
assert torch.equal(block.weight, weight)
replacement = nn.Parameter(torch.arange(4).reshape(2, 2).float())
backend._attach_mmap_param_attrs("weight", replacement, module.weight)
blocks[0].weight.data.zero_()
group.offload()
group.load()
for block, weight in zip(blocks, expected):
assert torch.equal(block.weight, weight)
assert replacement.mmap_weight_transform is transform
assert replacement.mmap_weight_transform_pending is True
group.offload()
assert all(block.weight.numel() == 0 for block in blocks)
def test_shared_allgather_output_is_narrowed_to_current_block(
self, dist_group, patched_offload_runtime, monkeypatch
@@ -598,7 +704,6 @@ class TestMmapWeightLoading:
OffloadConfig(
strategy=OffloadStrategy.DISTRIBUTED_LAYER_WISE,
pin_cpu_memory=False,
model_path=str(tmp_path),
),
torch.device("cpu"),
)
@@ -606,13 +711,81 @@ class TestMmapWeightLoading:
dits=[pipeline.transformer],
dit_names=["transformer"],
)
plan = HostWeightPlan(
backing_kind="checkpoint_mmap",
bindings={
name: TensorBinding(
checkpoint_key=name,
file_path=str(weight_file),
)
for name in weights
},
)
backend._load_weights_via_mmap(pipeline, modules)
backend._load_weights_via_mmap(pipeline, modules, plan)
assert pipeline.transformer.post_load_calls == 1
assert pipeline.transformer.time_embedder.weight.dtype == torch.float32
assert pipeline.transformer.blocks[0].weight.dtype == torch.bfloat16
def test_allgather_flag_with_group_size_one_uses_rank_local_mmap(
self,
tmp_path,
patched_offload_runtime,
):
class Transformer(nn.Module):
_layerwise_offload_blocks_attrs = ["blocks"]
def __init__(self):
super().__init__()
self.blocks = nn.ModuleList(
[
nn.Linear(2, 2, bias=False),
nn.Linear(2, 2, bias=False),
]
)
class Pipeline(nn.Module):
def __init__(self):
super().__init__()
self.transformer = Transformer()
@staticmethod
def _remap_ckpt_key(key):
return key
pipeline = Pipeline()
weights = {name: torch.ones_like(param) for name, param in pipeline.named_parameters()}
checkpoint_file = tmp_path / "model.safetensors"
save_file(weights, str(checkpoint_file))
result = build_checkpoint_mmap_plan(
pipeline,
dit_modules=(("transformer", pipeline.transformer),),
sources=(),
model_path=str(tmp_path),
tensor_parallel_size=1,
use_hsdp=False,
online_quantization=False,
)
assert result.plan is not None
backend = DistributedLayerwiseOffloadBackend(
OffloadConfig(
strategy=OffloadStrategy.DISTRIBUTED_LAYER_WISE,
pin_cpu_memory=False,
dp_size=1,
dlo_use_allgather=True,
),
torch.device("cpu"),
host_weight_plan=result.plan,
)
backend.enable(pipeline)
assert backend._using_rank_local_mmap
assert backend.dp_group is None
assert all(hook.rank_local_mmap for group in backend._all_hook_groups for hook in group)
backend.disable()
class TestGetBlocksFromDit:
def test_get_blocks_from_dit_single_block_attr(self):
@@ -878,23 +1051,123 @@ class TestOffloadPlan:
class TestMmapValidation:
"""Tests for mmap loader validation: TP rejection, strict check, validate_loaded_weights."""
"""Tests for loader preflight and backend plan realization."""
def test_tp_rejected_when_tp_world_size_gt_1(self, tmp_path, patched_offload_runtime, monkeypatch):
"""DLO+AllGather should reject when TP world size > 1."""
import json
from types import SimpleNamespace
from safetensors.torch import save_file
from vllm_omni.diffusion.offloader.base import OffloadConfig, OffloadStrategy
# Mock TP world size = 2
monkeypatch.setattr(
"vllm.distributed.parallel_state.get_tensor_model_parallel_world_size",
lambda: 2,
def test_component_source_prefix_builds_model_namespace(self, tmp_path):
source_root = tmp_path / "partition"
checkpoint_dir = source_root / "transformer"
checkpoint_dir.mkdir(parents=True)
checkpoint_file = checkpoint_dir / "model.safetensors"
save_file(
{"blocks.0.weight": torch.arange(4, dtype=torch.float32).reshape(1, 4)},
str(checkpoint_file),
)
class Pipeline(nn.Module):
def __init__(self):
super().__init__()
self.transformer = nn.Module()
self.transformer.blocks = nn.ModuleList([nn.Linear(4, 1, bias=False)])
self.weights_sources = [
SimpleNamespace(
model_or_path=str(source_root),
subfolder="transformer",
revision=None,
prefix="transformer.",
)
]
pipeline = Pipeline()
result = build_checkpoint_mmap_plan(
pipeline,
dit_modules=(("transformer", pipeline.transformer),),
sources=tuple(pipeline.weights_sources),
model_path=None,
tensor_parallel_size=1,
use_hsdp=False,
online_quantization=False,
)
assert result.fallback_reason is None
assert result.plan is not None
assert result.plan.bindings["transformer.blocks.0.weight"] == TensorBinding(
checkpoint_key="blocks.0.weight",
file_path=str(checkpoint_file),
)
assert result.plan.planned_source_prefixes == frozenset({"transformer."})
def test_non_dedicated_component_source_falls_back_before_discovery(self):
pipeline = nn.Module()
pipeline.transformer = nn.Linear(2, 2, bias=False)
sources = (
SimpleNamespace(
model_or_path="unused",
subfolder=None,
revision=None,
prefix="",
),
)
result = build_checkpoint_mmap_plan(
pipeline,
dit_modules=(("transformer", pipeline.transformer),),
sources=sources,
model_path=None,
tensor_parallel_size=1,
use_hsdp=False,
online_quantization=False,
)
assert result.plan is None
assert "dedicated component weight source" in result.fallback_reason
def test_preflight_falls_back_before_mutation_for_missing_model_tensors(self, tmp_path):
source_root = tmp_path / "partition"
checkpoint_dir = source_root / "transformer"
checkpoint_dir.mkdir(parents=True)
save_file(
{"blocks.0.weight": torch.ones((2, 2), dtype=torch.float32)},
str(checkpoint_dir / "model.safetensors"),
)
class Transformer(nn.Module):
_layerwise_offload_blocks_attrs = ["blocks"]
def __init__(self):
super().__init__()
self.blocks = nn.ModuleList([nn.Linear(2, 2, bias=False), nn.Linear(2, 2, bias=False)])
class Pipeline(nn.Module):
def __init__(self):
super().__init__()
self.transformer = Transformer()
self.weights_sources = [
SimpleNamespace(
model_or_path=str(source_root),
subfolder="transformer",
revision=None,
prefix="transformer.",
)
]
pipeline = Pipeline()
original_weight = pipeline.transformer.blocks[0].weight
result = build_checkpoint_mmap_plan(
pipeline,
dit_modules=(("transformer", pipeline.transformer),),
sources=tuple(pipeline.weights_sources),
model_path=None,
tensor_parallel_size=1,
use_hsdp=False,
online_quantization=False,
)
assert result.plan is None
assert "1 required DiT tensors" in result.fallback_reason
assert pipeline.transformer.blocks[0].weight is original_weight
assert not original_weight.is_meta
def test_tp_falls_back_before_checkpoint_discovery(self):
class SimpleModel(nn.Module):
_layerwise_offload_blocks_attrs = ["blocks"]
@@ -912,41 +1185,118 @@ class TestMmapValidation:
return key
pipeline = SimplePipeline()
weights = {name: torch.ones(p.shape, dtype=p.dtype) for name, p in pipeline.named_parameters() if not p.is_meta}
save_file(weights, str(tmp_path / "model.safetensors"))
(tmp_path / "model.safetensors.index.json").write_text(
json.dumps({"weight_map": {k: "model.safetensors" for k in weights}})
result = build_checkpoint_mmap_plan(
pipeline,
dit_modules=(("transformer", pipeline.transformer),),
sources=(),
model_path="unused",
tensor_parallel_size=2,
use_hsdp=False,
online_quantization=False,
)
backend = DistributedLayerwiseOffloadBackend(
OffloadConfig(
strategy=OffloadStrategy.DISTRIBUTED_LAYER_WISE,
pin_cpu_memory=False,
model_path=str(tmp_path),
),
torch.device("cpu"),
)
modules = SimpleNamespace(dits=[pipeline.transformer], dit_names=["transformer"])
assert result.plan is None
assert result.fallback_reason == "TP=2 requires the ordinary loader"
with pytest.raises(ValueError, match="Tensor Parallel"):
backend._load_weights_via_mmap(pipeline, modules)
@pytest.mark.parametrize(
("use_hsdp", "online_quantization", "expected_reason"),
[
(True, False, "HSDP requires the ordinary loader"),
(False, True, "online quantization requires the ordinary loader"),
],
)
def test_runtime_layouts_that_need_loader_callbacks_fall_back(
self,
use_hsdp,
online_quantization,
expected_reason,
):
pipeline = nn.Module()
pipeline.transformer = nn.Linear(2, 2, bias=False)
def test_tp_allowed_when_tp_world_size_eq_1(self, tmp_path, patched_offload_runtime, monkeypatch):
"""DLO+AllGather should work when TP world size = 1, even if params
have custom weight_loader attributes (e.g. QKVParallelLinear at TP=1)."""
import json
from types import SimpleNamespace
from safetensors.torch import save_file
from vllm_omni.diffusion.offloader.base import OffloadConfig, OffloadStrategy
# Mock TP world size = 1 (default)
monkeypatch.setattr(
"vllm.distributed.parallel_state.get_tensor_model_parallel_world_size",
lambda: 1,
result = build_checkpoint_mmap_plan(
pipeline,
dit_modules=(("transformer", pipeline.transformer),),
sources=(),
model_path="unused",
tensor_parallel_size=1,
use_hsdp=use_hsdp,
online_quantization=online_quantization,
)
assert result.plan is None
assert result.fallback_reason == expected_reason
@pytest.mark.parametrize(
("checkpoint_tensor", "expected_reason"),
[
(torch.ones((3, 2), dtype=torch.float32), "shape mismatch"),
(torch.ones((2, 2), dtype=torch.bfloat16), "dtype mismatch"),
],
)
def test_source_metadata_mismatch_falls_back(self, tmp_path, checkpoint_tensor, expected_reason):
checkpoint_file = tmp_path / "model.safetensors"
save_file({"transformer.weight": checkpoint_tensor}, str(checkpoint_file))
class Pipeline(nn.Module):
def __init__(self):
super().__init__()
self.transformer = nn.Linear(2, 2, bias=False)
@staticmethod
def _remap_ckpt_key(key):
return key
pipeline = Pipeline()
result = build_checkpoint_mmap_plan(
pipeline,
dit_modules=(("transformer", pipeline.transformer),),
sources=(),
model_path=str(tmp_path),
tensor_parallel_size=1,
use_hsdp=False,
online_quantization=False,
)
assert result.plan is None
assert expected_reason in result.fallback_reason
def test_non_persistent_buffers_do_not_need_checkpoint_bindings(self, tmp_path):
class Transformer(nn.Module):
def __init__(self):
super().__init__()
self.weight = nn.Parameter(torch.ones(2, 2))
self.register_buffer("derived", torch.ones(2), persistent=False)
checkpoint_file = tmp_path / "model.safetensors"
save_file({"transformer.weight": torch.ones(2, 2)}, str(checkpoint_file))
class Pipeline(nn.Module):
def __init__(self):
super().__init__()
self.transformer = Transformer()
@staticmethod
def _remap_ckpt_key(key):
return key
pipeline = Pipeline()
result = build_checkpoint_mmap_plan(
pipeline,
dit_modules=(("transformer", pipeline.transformer),),
sources=(),
model_path=str(tmp_path),
tensor_parallel_size=1,
use_hsdp=False,
online_quantization=False,
)
assert result.plan is not None
assert set(result.plan.bindings) == {"transformer.weight"}
def test_unadapted_custom_weight_loader_falls_back_at_tp1(self, tmp_path):
def custom_weight_loader(param, weight):
param.data.copy_(weight)
@@ -976,27 +1326,67 @@ class TestMmapValidation:
json.dumps({"weight_map": {k: "model.safetensors" for k in weights}})
)
backend = DistributedLayerwiseOffloadBackend(
OffloadConfig(
strategy=OffloadStrategy.DISTRIBUTED_LAYER_WISE,
pin_cpu_memory=False,
model_path=str(tmp_path),
),
torch.device("cpu"),
result = build_checkpoint_mmap_plan(
pipeline,
dit_modules=(("transformer", pipeline.transformer),),
sources=(),
model_path=str(tmp_path),
tensor_parallel_size=1,
use_hsdp=False,
online_quantization=False,
)
modules = SimpleNamespace(dits=[pipeline.transformer], dit_names=["transformer"])
# Should NOT raise — TP=1 is allowed even with custom weight_loader
backend._load_weights_via_mmap(pipeline, modules)
assert result.plan is None
assert "custom weight_loader" in result.fallback_reason
def test_cosmos3_adapter_preserves_existing_tp1_direct_mmap_contract(self, tmp_path):
from vllm_omni.diffusion.models.cosmos3.pipeline_cosmos3 import (
Cosmos3OmniDiffusersPipeline,
)
from vllm_omni.diffusion.models.cosmos3.transformer_cosmos3 import (
Cosmos3VFMTransformer,
)
transformer = object.__new__(Cosmos3VFMTransformer)
nn.Module.__init__(transformer)
transformer.proj_in = nn.Linear(2, 2, bias=False)
transformer.proj_in.weight.weight_loader = lambda *_args: None
pipeline = object.__new__(Cosmos3OmniDiffusersPipeline)
nn.Module.__init__(pipeline)
pipeline.transformer = transformer
source_root = tmp_path / "partition"
checkpoint_dir = source_root / "transformer"
checkpoint_dir.mkdir(parents=True)
checkpoint_file = checkpoint_dir / "model.safetensors"
save_file({"proj_in.weight": torch.ones(2, 2)}, str(checkpoint_file))
sources = (
SimpleNamespace(
model_or_path=str(source_root),
subfolder="transformer",
revision=None,
prefix="transformer.",
),
)
result = build_checkpoint_mmap_plan(
pipeline,
dit_modules=(("transformer", transformer),),
sources=sources,
model_path=None,
tensor_parallel_size=1,
use_hsdp=False,
online_quantization=False,
)
assert result.plan is not None
assert result.plan.bindings["transformer.proj_in.weight"] == TensorBinding(
checkpoint_key="proj_in.weight",
file_path=str(checkpoint_file),
)
def test_validate_loaded_weights_called(self, tmp_path, patched_offload_runtime):
"""validate_loaded_weights should be called after mmap loading."""
import json
from types import SimpleNamespace
from safetensors.torch import save_file
from vllm_omni.diffusion.offloader.base import OffloadConfig, OffloadStrategy
class ModelWithValidate(nn.Module):
_layerwise_offload_blocks_attrs = ["blocks"]
@@ -1038,19 +1428,64 @@ class TestMmapValidation:
backend = DistributedLayerwiseOffloadBackend(
OffloadConfig(
strategy=OffloadStrategy.DISTRIBUTED_LAYER_WISE, pin_cpu_memory=False, model_path=str(tmp_path)
strategy=OffloadStrategy.DISTRIBUTED_LAYER_WISE,
pin_cpu_memory=False,
),
torch.device("cpu"),
)
modules = SimpleNamespace(dits=[pipeline.transformer], dit_names=["transformer"])
result = build_checkpoint_mmap_plan(
pipeline,
dit_modules=(("transformer", pipeline.transformer),),
sources=(),
model_path=str(tmp_path),
tensor_parallel_size=1,
use_hsdp=False,
online_quantization=False,
)
backend._load_weights_via_mmap(pipeline, modules)
assert result.plan is not None
backend._load_weights_via_mmap(pipeline, modules, result.plan)
assert pipeline.transformer.validate_called, "validate_loaded_weights should be called"
class TestConfigValidation:
"""Tests for configuration validation in OffloadConfig / execute_request."""
def test_loader_plan_cannot_be_silently_dropped_on_unsupported_platform(self, monkeypatch):
import vllm_omni.diffusion.offloader as offloader_module
od_config = SimpleNamespace(
enable_cpu_offload=False,
enable_layerwise_offload=False,
enable_distributed_layerwise_offload=True,
dlo_use_allgather=False,
dlo_resident_layers=0,
pin_cpu_memory=False,
model="unused",
parallel_config=SimpleNamespace(
use_hsdp=False,
data_parallel_size=1,
sequence_parallel_size=1,
),
)
plan = HostWeightPlan(
backing_kind="checkpoint_mmap",
bindings={},
)
monkeypatch.setattr(
offloader_module.current_omni_platform,
"supports_cpu_offload",
lambda: False,
)
with pytest.raises(RuntimeError, match="skipped ordinary weight materialization"):
offloader_module.get_offload_backend(
od_config,
device=torch.device("cpu"),
host_weight_plan=plan,
)
def test_hsdp_with_allgather_rejected(self):
"""HSDP + DLO + AllGather should raise ValueError (double sharding)."""
from vllm_omni.diffusion.offloader.base import OffloadConfig