docs/source/Megatron-SWIFT/Ascend.md

# Ascend NPU

关于Megatron-SWIFT在Ascend NPU上的环境准备，请参考[NPU最佳实践](../BestPractices/NPU-support.md)。

## NPU 性能数据采集

NPU性能采集通过`torch_npu.profiler.profile`接口进行采集，创建torch_npu.profiler.profile对象，通过start和stop接口控制采集性能数据，采集过程需要修改ms-swift源码，修改swift/megatron/trainers/base.py文件中的train函数，采集示例如下：
```python
import torch_npu
...

experimental_config = torch_npu.profiler._ExperimentalConfig(
    profiler_level=torch_npu.profiler.ProfilerLevel.Level1,
    aic_metrics=torch_npu.profiler.AiCMetrics.PipeUtilization,
)

prof = torch_npu.profiler.profile(
    activities=[
        torch_npu.profiler.ProfilerActivity.CPU,
        torch_npu.profiler.ProfilerActivity.NPU
        ],
    schedule=torch_npu.profiler.schedule(wait=0, warmup=0, active=1, repeat=1, skip_first=6),
    on_trace_ready=torch_npu.profiler.tensorboard_trace_handler("./result"),
    profile_memory=False, # 关闭采集内存信息
    with_stack=False,    # 关闭采集堆栈信息
    experimental_config=experimental_config)
prof.start()
# ms-swift 逻辑
while state.iteration < args.train_iters:
  ...
  metric, grad_norm, update_successful = train_step(train_data_iterator)
  # 性能数据采集
  prof.step()
  ...
prof.stop()
```

## NPU 精度数据采集
### 安装msprobe
```shell
pip install mindstudio-probe
```

### 代码修改
为了支持 msprobe 工具进行精度调试，我们需要修改 `swift/megatron/model/mm_gpt_model.py` 文件中的 `_patch_word_embeddings` 函数。主要改动是调整函数参数和内部实现逻辑，使其能够正确地对嵌入层进行patch

下面是具体的修改内容：

修改前：
```python
def _patch_word_embeddings(self, kwargs):
    origin_forward = VocabParallelEmbedding.forward

    def forward(_self, input_):
        args = get_args()
        reduce_scatter_embeddings = _self.reduce_scatter_embeddings
        _self.reduce_scatter_embeddings = False
        input_ = torch.masked_fill(input_, input_ < 0, 0)
        res = origin_forward(_self, input_)
        _self.reduce_scatter_embeddings = reduce_scatter_embeddings
        packed_seq_params = kwargs.get('packed_seq_params')
        # ...其他逻辑...
        return res
    VocabParallelEmbedding.forward = forward
    try:
        yield
    finally:
        VocabParallelEmbedding.forward = origin_forward

def forward(
    self,
    input_ids: torch.Tensor,
    position_ids: torch.Tensor,
    attention_mask: torch.Tensor = None,
    decoder_input: torch.Tensor = None,
    labels: torch.Tensor = None,
    inference_params: InferenceParams = None,
    packed_seq_params: PackedSeqParams = None,
    **kwargs,
) -> torch.Tensor:
    if decoder_input is not None:
        pass
    elif self.pre_process:
        kwargs.update({'input_ids': input_ids, 'packed_seq_params': packed_seq_params})
        with self._patch_word_embeddings(kwargs):
            decoder_input = self.language_model.embedding(input_ids=input_ids, position_ids=position_ids)

    # ...其他逻辑...
```

修改后：
```python
def _patch_word_embeddings(self, kwargs, emb):          # 修改1
    origin_forward = emb.word_embeddings.forward        # 修改2

    def forward(input_):                                # 修改3
        args = get_args()
        _self = emb.word_embeddings                     # 修改4
        reduce_scatter_embeddings = _self.reduce_scatter_embeddings
        _self.reduce_scatter_embeddings = False
        input_ = torch.masked_fill(input_, input_ < 0, 0)
        res = origin_forward(input_)                    # 修改5
        _self.reduce_scatter_embeddings = reduce_scatter_embeddings
        packed_seq_params = kwargs.get('packed_seq_params')
        # ...其他逻辑...
        return res

    emb.word_embeddings.forward = forward               # 修改6
    try:
        yield
    finally:
        emb.word_embeddings.forward = origin_forward    # 修改7

def forward(
    self,
    input_ids: torch.Tensor,
    position_ids: torch.Tensor,
    attention_mask: torch.Tensor = None,
    decoder_input: torch.Tensor = None,
    labels: torch.Tensor = None,
    inference_params: InferenceParams = None,
    packed_seq_params: PackedSeqParams = None,
    **kwargs,
) -> torch.Tensor:
    if decoder_input is not None:
        pass
    elif self.pre_process:
        kwargs.update({'input_ids': input_ids, 'packed_seq_params': packed_seq_params})
        with self._patch_word_embeddings(kwargs, self.language_model.embedding):                # 修改8
            decoder_input = self.language_model.embedding(input_ids=input_ids, position_ids=position_ids)

    # ...其他逻辑...
```

主要变化包括：
1. `_patch_word_embeddings` 方法增加了 `emb` 参数，用于接收 embedding 模块实例
2. 直接获取 `emb.word_embeddings.forward` 而不是 `VocabParallelEmbedding.forward`
3. 内部 `forward` 函数签名从 `(_self, input_)` 改为 `(input_)`
4. 在函数内部通过 `emb.word_embeddings` 获取 `_self`
5. 调用原始 forward 时直接传入 `input_`
6. 使用 `emb.word_embeddings.forward` 进行替换和恢复操作（修改6、7）
7. 在调用 `_patch_word_embeddings` 时传入 `self.language_model.embedding` 实例

对文件swift/megatron/trainers/base.py中的train_step函数进行修改
修改前：
```python
def train_step(self, forward_step_func, data_iterator, model, optimizer, opt_param_scheduler, config, *args,
               **kwargs):
    new_data_iterator = self._replace_data_iterator(data_iterator, model)
    return self._origin_train_step(forward_step_func, new_data_iterator, model, optimizer, opt_param_scheduler,
                                   config, *args, **kwargs)

```
修改后：
```python
def train_step(self, forward_step_func, data_iterator, model, optimizer, opt_param_scheduler, config, *args,
               **kwargs):
    new_data_iterator = self._replace_data_iterator(data_iterator, model)
    from msprobe.pytorch import PrecisionDebugger
    debugger = PrecisionDebugger(dump_path='./dump_path', level='mix', model=model)
    debugger.start()
    try:
        origin_train_step_out = self._origin_train_step(
            forward_step_func, new_data_iterator, model, optimizer, opt_param_scheduler,config, *args, **kwargs)
    finally:
        debugger.stop()
        debugger.step()
    return origin_train_step_out
```


### 使能

另外，由于msprobe不支持融合计算，需要在启动脚本添加`--bias_dropout_fusion false`、`--bias_swiglu_fusion false`、`--cross_entropy_loss_fusion false`

#### 示例
```shell
PYTORCH_NPU_ALLOC_CONF='expandable_segments:True' \
NPROC_PER_NODE=2 \
CUDA_VISIBLE_DEVICES=0,1 \
megatron sft \
    --mcore_model Qwen2.5-7B-Instruct-mcore \
    --dataset 'AI-ModelScope/alpaca-gpt4-data-zh#500' \
              'AI-ModelScope/alpaca-gpt4-data-en#500' \
              'swift/self-cognition#500' \
    --tensor_model_parallel_size 2 \
    ...
    --bias_dropout_fusion false \
    --bias_swiglu_fusion false \
    --cross_entropy_loss_fusion false
```