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Merged
merged 3 commits into from
Jul 23, 2024
Merged

Do dtype conversion in torch hook to save memory #1384

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f008b68
Do dtype conversion in torch hook to save memory
irenedea Jul 22, 2024
26db1c2
update code comment
irenedea Jul 23, 2024
5ee5f6f
Merge branch 'main' into checkpointer-oom
irenedea Jul 23, 2024
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24 changes: 11 additions & 13 deletions llmfoundry/callbacks/hf_checkpointer.py
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Original file line number Diff line number Diff line change
Expand Up @@ -436,7 +436,7 @@ def _save_checkpoint(self, state: State, logger: Logger):
cpu_offload = True

# Add a dtensor->cpu tensor hook to avoid CUDA OOM
def dtensor_to_tensor_hook(
def tensor_hook(
module: nn.Module,
state_dict: Dict[str, Any],
prefix: str,
Expand All @@ -449,20 +449,23 @@ def dtensor_to_tensor_hook(
dtensor_fqns.append(fqn)
tensor = tensor.full_tensor() # type: ignore
if dist.get_global_rank() == 0:
# Offload any DTensors to CPU
if cpu_offload:
tensor = tensor.cpu()
state_dict[fqn] = tensor
else:
state_dict[fqn] = None
# Convert the state dict to the requested precision
if isinstance(tensor, torch.Tensor):
state_dict[fqn] = tensor.to(dtype=self.dtype)
del tensor
if dist.get_global_rank() != 0:
for fqn in dtensor_fqns:
del state_dict[fqn]
state_dict = {}
return state_dict

hooks = []
for _, module in state_dict_model.named_modules():
if isinstance(module, FSDP):
hooks.append(
module._register_state_dict_hook(dtensor_to_tensor_hook),
)
hooks.append(module._register_state_dict_hook(tensor_hook),)

state_dict = get_model_state_dict(
state_dict_model,
Expand All @@ -474,11 +477,6 @@ def dtensor_to_tensor_hook(
for hook in hooks:
hook.remove()

# Convert the state dict to the requested precision
for k, v in state_dict.items():
if isinstance(v, torch.Tensor):
state_dict[k] = v.to(dtype=self.dtype)

new_model_instance = None # Need this for pyright because variable could be unbound

if dist.get_global_rank() == 0:
Expand Down Expand Up @@ -537,7 +535,7 @@ def dtensor_to_tensor_hook(
original_tokenizer.save_pretrained(temp_save_dir)

# Only need to edit files for MPT because it has custom code
if original_model.config.model_type == 'mpt':
if new_model_instance.config.model_type == 'mpt':
log.debug('Editing MPT files for HuggingFace compatibility')
edit_files_for_hf_compatibility(
temp_save_dir,
Expand Down
2 changes: 2 additions & 0 deletions tests/a_scripts/inference/test_convert_composer_to_hf.py
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Expand Up @@ -383,6 +383,8 @@ def test_huggingface_conversion_callback_interval(
mlflow_logger_mock.model_registry_prefix = ''
mlflow_logger_mock._experiment_id = 'mlflow-experiment-id'
mlflow_logger_mock._run_id = 'mlflow-run-id'
mlflow_logger_mock._enabled = True
mlflow_logger_mock.run_url = 'fake-url'
checkpointer_callback.transform_model_pre_registration = MagicMock(
wraps=checkpointer_callback.transform_model_pre_registration,
)
Expand Down
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