ColossalAI/colossalai/shardformer/policies/llama.py

295 lines
11 KiB
Python

import warnings
from functools import partial
from typing import Callable, Dict, List, Union
import torch.nn as nn
from torch import Tensor
from torch.nn import Module
from colossalai.shardformer.layer import FusedRMSNorm, Linear1D_Col, Linear1D_Row, RMSNorm, VocabParallelEmbedding1D
from ..modeling.llama import LlamaPipelineForwards, get_llama_flash_attention_forward, get_lm_forward_with_dist_cross_entropy
from .base_policy import ModulePolicyDescription, Policy, SubModuleReplacementDescription
__all__ = ["LlamaPolicy", "LlamaForCausalLMPolicy", "LlamaForSequenceClassificationPolicy"]
class LlamaPolicy(Policy):
def config_sanity_check(self):
pass
def preprocess(self):
if self.shard_config.enable_tensor_parallelism:
# Resize embedding
vocab_size = self.model.config.vocab_size
world_size = self.shard_config.tensor_parallel_size
if vocab_size % world_size != 0:
new_vocab_size = vocab_size + world_size - vocab_size % world_size
self.model.resize_token_embeddings(new_vocab_size)
return self.model
def module_policy(self) -> Dict[Union[str, nn.Module], ModulePolicyDescription]:
from transformers.models.llama.modeling_llama import LlamaAttention, LlamaDecoderLayer, LlamaModel
policy = {}
if self.shard_config.enable_fused_normalization:
norm_cls = FusedRMSNorm
else:
norm_cls = RMSNorm
if self.shard_config.enable_sequence_parallelism:
self.shard_config.enable_sequence_parallelism = False
warnings.warn("Llama dosen't support sequence parallelism now, will ignore the sequence parallelism flag.")
if self.shard_config.enable_tensor_parallelism:
decoder_attribute_replacement = {
"self_attn.hidden_size": self.model.config.hidden_size // self.shard_config.tensor_parallel_size,
"self_attn.num_heads": self.model.config.num_attention_heads // self.shard_config.tensor_parallel_size,
}
if getattr(self.model.config, "num_key_value_heads", False):
decoder_attribute_replacement["self_attn.num_key_value_heads"] = (
self.model.config.num_key_value_heads // self.shard_config.tensor_parallel_size
)
policy[LlamaDecoderLayer] = ModulePolicyDescription(
attribute_replacement=decoder_attribute_replacement,
sub_module_replacement=[
SubModuleReplacementDescription(
suffix="self_attn.q_proj",
target_module=Linear1D_Col,
),
SubModuleReplacementDescription(
suffix="self_attn.k_proj",
target_module=Linear1D_Col,
),
SubModuleReplacementDescription(
suffix="self_attn.v_proj",
target_module=Linear1D_Col,
),
SubModuleReplacementDescription(
suffix="self_attn.o_proj",
target_module=Linear1D_Row,
),
SubModuleReplacementDescription(
suffix="mlp.gate_proj",
target_module=Linear1D_Col,
),
SubModuleReplacementDescription(
suffix="mlp.up_proj",
target_module=Linear1D_Col,
),
SubModuleReplacementDescription(
suffix="mlp.down_proj",
target_module=Linear1D_Row,
),
],
)
self.append_or_create_submodule_replacement(
description=SubModuleReplacementDescription(
suffix="embed_tokens",
target_module=VocabParallelEmbedding1D,
),
policy=policy,
target_key=LlamaModel,
)
# optimization configuration
self.append_or_create_submodule_replacement(
description=[
SubModuleReplacementDescription(
suffix="input_layernorm",
target_module=norm_cls,
),
SubModuleReplacementDescription(
suffix="post_attention_layernorm",
target_module=norm_cls,
),
],
policy=policy,
target_key=LlamaDecoderLayer,
)
self.append_or_create_submodule_replacement(
description=SubModuleReplacementDescription(
suffix="norm",
target_module=norm_cls,
),
policy=policy,
target_key=LlamaModel,
)
# use flash attention
if self.shard_config.enable_flash_attention:
self.append_or_create_method_replacement(
description={
"forward": get_llama_flash_attention_forward(),
},
policy=policy,
target_key=LlamaAttention,
)
return policy
def postprocess(self):
return self.model
def set_pipeline_forward(self, model_cls: nn.Module, new_forward: Callable, policy: Dict) -> None:
"""If under pipeline parallel setting, replacing the original forward method of huggingface
to customized forward method, and add this changing to policy."""
if self.pipeline_stage_manager:
stage_manager = self.pipeline_stage_manager
if self.model.__class__.__name__ == "LlamaModel":
module = self.model
else:
module = self.model.model
layers_per_stage = Policy.distribute_layers(len(module.layers), stage_manager.num_stages)
stage_index = Policy.get_stage_index(layers_per_stage, stage_manager.stage)
method_replacement = {"forward": partial(new_forward, stage_manager=stage_manager, stage_index=stage_index, shard_config=self.shard_config)}
self.append_or_create_method_replacement(
description=method_replacement, policy=policy, target_key=model_cls
)
return
def get_held_layers(self) -> List[Module]:
"""Get pipeline layers for current stage."""
assert self.pipeline_stage_manager is not None
if self.model.__class__.__name__ == "LlamaModel":
module = self.model
else:
module = self.model.model
stage_manager = self.pipeline_stage_manager
held_layers = []
layers_per_stage = self.distribute_layers(len(module.layers), stage_manager.num_stages)
if stage_manager.is_first_stage():
held_layers.append(module.embed_tokens)
start_idx, end_idx = self.get_stage_index(layers_per_stage, stage_manager.stage)
held_layers.extend(module.layers[start_idx:end_idx])
if stage_manager.is_last_stage():
held_layers.append(module.norm)
return held_layers
class LlamaModelPolicy(LlamaPolicy):
def module_policy(self):
policy = super().module_policy()
from transformers.models.llama.modeling_llama import LlamaModel
if self.pipeline_stage_manager:
# set None as default
self.set_pipeline_forward(
model_cls=LlamaModel, new_forward=LlamaPipelineForwards.llama_model_forward, policy=policy
)
return policy
def get_held_layers(self) -> List[Module]:
"""Get pipeline layers for current stage."""
held_layers = super().get_held_layers()
return held_layers
def get_shared_params(self) -> List[Dict[int, Tensor]]:
"""No shared params in llama model"""
return []
class LlamaForCausalLMPolicy(LlamaPolicy):
def module_policy(self):
from transformers import LlamaForCausalLM
policy = super().module_policy()
if self.shard_config.enable_tensor_parallelism:
# add a new item for casual lm
new_item = {
LlamaForCausalLM: ModulePolicyDescription(
sub_module_replacement=[
SubModuleReplacementDescription(
suffix="lm_head", target_module=Linear1D_Col
)
],
method_replacement={"forward": get_lm_forward_with_dist_cross_entropy(self.shard_config)}
)
}
policy.update(new_item)
if self.pipeline_stage_manager:
# set None as default
self.set_pipeline_forward(
model_cls=LlamaForCausalLM, new_forward=LlamaPipelineForwards.llama_for_causal_lm_forward, policy=policy
)
return policy
def get_held_layers(self) -> List[Module]:
"""Get pipeline layers for current stage."""
stage_manager = self.pipeline_stage_manager
held_layers = super().get_held_layers()
if stage_manager.is_last_stage():
held_layers.append(self.model.lm_head)
return held_layers
def get_shared_params(self) -> List[Dict[int, Tensor]]:
llama_model = self.model.model
if self.pipeline_stage_manager and self.pipeline_stage_manager.num_stages > 1:
if (
id(llama_model.embed_tokens.weight) == id(self.model.lm_head.weight)
and self.pipeline_stage_manager.num_stages > 1
):
# tie weights
return [
{
0: llama_model.embed_tokens.weight,
self.pipeline_stage_manager.num_stages - 1: self.model.lm_head.weight,
}
]
return []
class LlamaForSequenceClassificationPolicy(LlamaPolicy):
def module_policy(self):
from transformers import LlamaForSequenceClassification
policy = super().module_policy()
if self.shard_config.enable_tensor_parallelism:
# add a new item for sequence classification
new_item = {
LlamaForSequenceClassification: ModulePolicyDescription(
sub_module_replacement=[
SubModuleReplacementDescription(
suffix="score", target_module=Linear1D_Col, kwargs=dict(gather_output=True)
)
]
)
}
policy.update(new_item)
# to be confirmed
if self.pipeline_stage_manager:
# set None as default
self.set_pipeline_forward(
model_cls=LlamaForSequenceClassification,
new_forward=LlamaPipelineForwards.llama_for_sequence_classification_forward,
policy=policy,
)
return policy
def get_held_layers(self) -> List[Module]:
"""Get pipeline layers for current stage."""
stage_manager = self.pipeline_stage_manager
held_layers = super().get_held_layers()
if stage_manager.is_last_stage():
held_layers.append(self.model.score)
return held_layers
def get_shared_params(self) -> List[Dict[int, Tensor]]:
"""No shared params in llama for sequence classification model"""
return []