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wehub-resource-sync a203934033
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chore: import upstream snapshot with attribution
2026-07-13 13:34:58 +08:00

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Python

# Copyright (c) ModelScope Contributors. All rights reserved.
"""NPU-only Megatron checkpoint compatibility helpers.
MindSpeed patches Megatron's distributed optimizer on NPU, but some Megatron-Core
checkpoint formats still need the native Megatron param_state loaders.
"""
from __future__ import annotations
import torch
from contextlib import contextmanager
from swift.utils import get_logger
logger = get_logger()
def _iter_optimizer_param_groups(optimizer):
visited = set()
def visit(obj):
if obj is None or id(obj) in visited:
return
visited.add(id(obj))
param_groups = getattr(obj, 'param_groups', None)
if param_groups is not None:
yield param_groups
inner_optimizer = getattr(obj, 'optimizer', None)
if inner_optimizer is not obj:
yield from visit(inner_optimizer)
for child in getattr(obj, 'chained_optimizers', []) or []:
yield from visit(child)
for child in getattr(obj, 'sub_optimizers', []) or []:
yield from visit(child)
yield from visit(optimizer)
def _step_to_int(step):
if isinstance(step, torch.Tensor):
if step.numel() != 1:
raise RuntimeError(f'Optimizer step tensor must be scalar, got shape: {tuple(step.shape)}')
return int(step.item())
return int(step)
@contextmanager
def _canonicalize_optimizer_steps_for_checkpoint(optimizer):
"""Normalize NPU scalar step tensors while Megatron builds optimizer checkpoint state.
Megatron-Core deduplicates param-group steps with set(). Equal NPU scalar
tensors can still hash as distinct objects, so use their numeric value only
while sharded_state_dict() is being built and restore the optimizer in place.
"""
saved_steps = []
numeric_steps = set()
for param_groups in _iter_optimizer_param_groups(optimizer):
for param_group in param_groups:
if len(param_group.get('params', [])) == 0 or 'step' not in param_group:
continue
step = param_group['step']
numeric_step = _step_to_int(step)
saved_steps.append((param_group, step))
numeric_steps.add(numeric_step)
if len(numeric_steps) > 1:
raise RuntimeError(f'Inconsistent optimizer steps before checkpoint save: {sorted(numeric_steps)}')
canonical_step = next(iter(numeric_steps), None)
try:
if canonical_step is not None:
for param_group, _step in saved_steps:
param_group['step'] = canonical_step
if any(isinstance(step, torch.Tensor) for _param_group, step in saved_steps):
logger.warning(f'Canonicalized optimizer param-group step to {canonical_step} for checkpoint save.')
yield
finally:
for param_group, step in saved_steps:
param_group['step'] = step
def optimizer_sharded_state_dict(optimizer, state_dict, **optim_sd_kwargs):
with _canonicalize_optimizer_steps_for_checkpoint(optimizer):
return optimizer.sharded_state_dict(state_dict, **optim_sd_kwargs)
def _iter_distributed_optimizers(optimizer):
visited = set()
def visit(obj):
if obj is None or id(obj) in visited:
return
visited.add(id(obj))
if hasattr(obj, 'load_parameter_state_from_dp_reshardable') or hasattr(
obj, 'load_parameter_state_from_fully_reshardable'):
yield obj
return
for child in getattr(obj, 'chained_optimizers', []) or []:
yield from visit(child)
for child in getattr(obj, 'sub_optimizers', []) or []:
yield from visit(child)
yield from visit(optimizer)
def _has_mindspeed_patched_load_state_dict(distributed_optimizer):
load_state_dict = getattr(type(distributed_optimizer), 'load_state_dict', None)
return getattr(load_state_dict, '__module__', '').startswith('mindspeed.')
_MEGATRON_RESHARDABLE_PARAM_STATE_LOADERS = {
'dp_reshardable': 'load_parameter_state_from_dp_reshardable',
'fully_reshardable': 'load_parameter_state_from_fully_reshardable',
}
def _current_npu_device():
if hasattr(torch, 'npu'):
return torch.device('npu', torch.npu.current_device())
return torch.cuda.current_device()
def _restore_mindspeed_optimizer_step_tensors(optimizer):
restored_count = 0
for param_groups in _iter_optimizer_param_groups(optimizer):
for param_group in param_groups:
step = param_group.get('step')
if isinstance(step, torch.Tensor):
continue
if isinstance(step, (int, float)):
param_group['step'] = torch.tensor(int(step), dtype=torch.int64, device=_current_npu_device())
restored_count += 1
if restored_count:
logger.warning(f'Restored {restored_count} MindSpeed optimizer param-group step values to NPU tensors.')
def _split_chained_optimizer_state_dict(chained_optimizers, state_dict):
if isinstance(state_dict, dict):
state_dicts = [v for _k, v in sorted(state_dict.items())]
else:
state_dicts = list(state_dict)
if len(chained_optimizers) != len(state_dicts):
raise RuntimeError(
f'Expected {len(chained_optimizers)} entries in optimizer state dict, but got {len(state_dicts)}.')
return state_dicts
def _load_chained_optimizer_state_dict(optimizer, state_dict):
chained_optimizers = getattr(optimizer, 'chained_optimizers', None)
if not chained_optimizers or len(chained_optimizers) <= 1:
return False
state_dicts = _split_chained_optimizer_state_dict(chained_optimizers, state_dict)
for child_optimizer, child_state_dict in zip(chained_optimizers, state_dicts):
load_optimizer_state_dict(child_optimizer, child_state_dict)
synchronize_steps = getattr(optimizer, '_synchronize_steps', None)
if synchronize_steps is not None:
synchronize_steps()
return True
def load_optimizer_state_dict(optimizer, state_dict):
if _load_chained_optimizer_state_dict(optimizer, state_dict):
return
distributed_optimizers = list(_iter_distributed_optimizers(optimizer))
mindspeed_patched = any(
_has_mindspeed_patched_load_state_dict(distributed_optimizer)
for distributed_optimizer in distributed_optimizers)
sharding_type = state_dict.get('param_state_sharding_type') if isinstance(state_dict, dict) else None
native_loader_name = _MEGATRON_RESHARDABLE_PARAM_STATE_LOADERS.get(sharding_type)
if native_loader_name is None:
optimizer.load_state_dict(state_dict)
if mindspeed_patched:
_restore_mindspeed_optimizer_step_tensors(optimizer)
return
if not mindspeed_patched:
optimizer.load_state_dict(state_dict)
return
if len(distributed_optimizers) != 1:
raise RuntimeError(f'MindSpeed optimizer checkpoint compatibility supports exactly one distributed optimizer, '
f'got {len(distributed_optimizers)}.')
distributed_optimizer = distributed_optimizers[0]
if not hasattr(distributed_optimizer, native_loader_name):
raise RuntimeError(f'Distributed optimizer does not support sharding type {sharding_type}.')
state_dict_without_param_state = dict(state_dict)
param_state = state_dict_without_param_state.pop('param_state', None)
state_dict_without_param_state.pop('param_state_sharding_type', None)
if param_state is None:
raise RuntimeError(f'Optimizer checkpoint missing param_state for sharding type {sharding_type}.')
logger.warning(f'Loading optimizer param_state with ms-swift compatibility path because MindSpeed '
f'DistributedOptimizer.load_state_dict does not support {sharding_type}.')
# Let MindSpeed restore the generic optimizer state; load the missing
# reshardable param_state with Megatron-Core's native implementation.
optimizer.load_state_dict(state_dict_without_param_state)
_restore_mindspeed_optimizer_step_tensors(optimizer)
getattr(distributed_optimizer, native_loader_name)(param_state)
__all__ = ['load_optimizer_state_dict', 'optimizer_sharded_state_dict']