Recast disk weights with dtype overrides

This commit is contained in:
ifilipis 2026-01-08 20:43:08 +02:00
parent 1ec01dd023
commit 5c60954448
2 changed files with 64 additions and 8 deletions

View File

@ -665,8 +665,17 @@ def ensure_module_materialized(
if current is None:
continue
if current.device.type != "meta" and current.device == target_device:
if current.device.type == "cpu":
CACHE.touch(module, name)
if dtype_override is not None and current.dtype != dtype_override:
tensor = current.to(device=target_device, dtype=dtype_override)
if is_buffer:
module._buffers[name] = tensor
else:
module._parameters[name] = torch.nn.Parameter(tensor, requires_grad=disk_ref.requires_grad)
if tensor.device.type == "cpu":
CACHE.record(module, name, tensor, is_buffer=is_buffer)
else:
if current.device.type == "cpu":
CACHE.touch(module, name)
continue
meta_nbytes = _meta_nbytes(disk_ref.meta)
if meta_nbytes is None:
@ -704,7 +713,7 @@ def ensure_module_materialized(
_log_materialization(module, target_device, free_mem_start, refs, state, "Disk weight materialized")
def disk_weight_pre_hook(module: torch.nn.Module, args, kwargs):
def disk_weight_pre_hook(module: torch.nn.Module, args, kwargs={}):
if not REGISTRY.has(module) and module not in LAZY_MODULE_STATE:
return
input_dtype = _find_tensor_dtype(args, kwargs)
@ -740,11 +749,15 @@ def evict_ram_cache(bytes_to_free: int):
return CACHE.evict_bytes(bytes_to_free)
def materialize_module_tree(module: torch.nn.Module, target_device: torch.device):
def materialize_module_tree(
module: torch.nn.Module,
target_device: torch.device,
dtype_override: Optional[torch.dtype] = None,
):
if not disk_weights_enabled():
return
for submodule in module.modules():
ensure_module_materialized(submodule, target_device)
ensure_module_materialized(submodule, target_device, dtype_override=dtype_override)
def _extract_to_device(args, kwargs) -> Optional[torch.device]:
@ -758,6 +771,15 @@ def _extract_to_device(args, kwargs) -> Optional[torch.device]:
return None
def _extract_to_dtype(args, kwargs) -> Optional[torch.dtype]:
if "dtype" in kwargs and kwargs["dtype"] is not None:
return kwargs["dtype"]
for arg in args:
if isinstance(arg, torch.dtype):
return arg
return None
def _find_existing_device(module: torch.nn.Module) -> Optional[torch.device]:
for param in module.parameters(recurse=True):
if param is not None and param.device.type != "meta":
@ -771,9 +793,12 @@ def _find_existing_device(module: torch.nn.Module) -> Optional[torch.device]:
def module_to(module: torch.nn.Module, *args, **kwargs):
if disk_weights_enabled():
target_device = _extract_to_device(args, kwargs)
dtype_override = _extract_to_dtype(args, kwargs)
if target_device is None:
target_device = _find_existing_device(module) or torch.device("cpu")
materialize_module_tree(module, target_device)
if dtype_override is None:
dtype_override = getattr(module, "manual_cast_dtype", None)
materialize_module_tree(module, target_device, dtype_override=dtype_override)
return module.to(*args, **kwargs)
@ -976,18 +1001,21 @@ def lazy_load_state_dict(model: torch.nn.Module, state_dict, strict: bool = Fals
if error_msgs:
raise RuntimeError("Error(s) in loading state_dict:\n\t{}".format("\n\t".join(error_msgs)))
dtype_override = getattr(model, "manual_cast_dtype", None)
for name, param in model.named_parameters(recurse=True):
if name not in state_keys:
continue
meta = state_dict.meta(name)
meta_tensor = torch.empty(meta.shape, dtype=meta.dtype, device="meta")
meta_dtype = dtype_override or meta.dtype
meta_tensor = torch.empty(meta.shape, dtype=meta_dtype, device="meta")
_replace_tensor(model, name, meta_tensor, is_buffer=False, requires_grad=param.requires_grad)
for name, buf in model.named_buffers(recurse=True):
if buf is None or name not in state_keys:
continue
meta = state_dict.meta(name)
meta_tensor = torch.empty(meta.shape, dtype=meta.dtype, device="meta")
meta_dtype = dtype_override or meta.dtype
meta_tensor = torch.empty(meta.shape, dtype=meta_dtype, device="meta")
_replace_tensor(model, name, meta_tensor, is_buffer=True, requires_grad=False)
register_module_weights(model, state_dict)

View File

@ -180,3 +180,31 @@ def test_lazy_disk_weights_loads_on_demand(tmp_path, monkeypatch):
assert len(calls) == 2
finally:
comfy.disk_weights.configure(prev_cache, allow_gds=prev_gds, pin_if_cpu=prev_pin, enabled=prev_enabled)
def test_lazy_disk_weights_respects_dtype_override(tmp_path):
if importlib.util.find_spec("fastsafetensors") is None:
pytest.skip("fastsafetensors not installed")
import comfy.utils
import comfy.disk_weights
prev_cache = comfy.disk_weights.CACHE.max_bytes
prev_gds = comfy.disk_weights.ALLOW_GDS
prev_pin = comfy.disk_weights.PIN_IF_CPU
prev_enabled = comfy.disk_weights.DISK_WEIGHTS_ENABLED
comfy.disk_weights.configure(0, allow_gds=False, pin_if_cpu=False, enabled=True)
try:
path = _write_safetensors(tmp_path, {"weight": torch.zeros((4, 4), dtype=torch.bfloat16), "bias": torch.zeros((4,), dtype=torch.bfloat16)})
sd = comfy.utils.load_torch_file(path, safe_load=True)
model = torch.nn.Linear(4, 4, bias=True)
comfy.utils.load_state_dict(model, sd, strict=True)
assert model.weight.device.type == "meta"
comfy.disk_weights.ensure_module_materialized(model, torch.device("cpu"))
assert model.weight.dtype == torch.bfloat16
comfy.disk_weights.ensure_module_materialized(model, torch.device("cpu"), dtype_override=torch.float16)
assert model.weight.dtype == torch.float16
finally:
comfy.disk_weights.configure(prev_cache, allow_gds=prev_gds, pin_if_cpu=prev_pin, enabled=prev_enabled)