ColossalAI/colossalai/shardformer/policies/llama.py

427 lines
17 KiB
Python

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,
PaddingEmbedding,
PaddingLMHead,
RMSNorm,
VocabParallelEmbedding1D,
VocabParallelLMHead1D,
)
from ..modeling.llama import (
LlamaPipelineForwards,
get_llama_flash_attention_forward,
get_llama_flash_attention_model_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):
self.tie_weight = self.tie_weight_check()
self.origin_attn_implement = self.model.config._attn_implementation
return self.model
def module_policy(self) -> Dict[Union[str, nn.Module], ModulePolicyDescription]:
from transformers.models.llama.modeling_llama import (
LlamaAttention,
LlamaDecoderLayer,
LlamaFlashAttention2,
LlamaModel,
LlamaSdpaAttention,
)
ATTN_IMPLEMENTATION = {
"eager": LlamaAttention,
"flash_attention_2": LlamaFlashAttention2,
"sdpa": LlamaSdpaAttention,
}
policy = {}
attn_cls = ATTN_IMPLEMENTATION[self.origin_attn_implement]
embedding_cls = None
if self.shard_config.enable_tensor_parallelism:
embedding_cls = VocabParallelEmbedding1D
else:
if self.tie_weight:
embedding_cls = PaddingEmbedding
if self.shard_config.enable_fused_normalization:
norm_cls = FusedRMSNorm
else:
norm_cls = RMSNorm
sp_mode = self.shard_config.sequence_parallelism_mode or None
sp_size = self.shard_config.sequence_parallel_size or None
sp_group = self.shard_config.sequence_parallel_process_group or None
sp_partial_derived = sp_mode in ["split_gather", "ring"]
if sp_mode == "ring_attn" and not self.is_causal:
raise ValueError("Ring attention is only meant for causal language modeling.")
tp_size = self.shard_config.tensor_parallel_size
# Modified by SP and TP
num_q_heads = self.model.config.num_attention_heads
num_kv_heads = getattr(self.model.config, "num_key_value_heads", None)
if sp_mode == "all_to_all":
num_q_heads //= sp_size
decoder_attribute_replacement = {"num_heads": num_q_heads}
if num_kv_heads:
num_kv_heads //= sp_size
decoder_attribute_replacement["num_key_value_heads"] = num_kv_heads
policy[attn_cls] = ModulePolicyDescription(
attribute_replacement=decoder_attribute_replacement,
)
if self.shard_config.enable_flash_attention or self.shard_config.enable_sequence_parallelism:
self.append_or_create_method_replacement(
description={
"forward": get_llama_flash_attention_forward(self.shard_config, sp_mode, sp_size, sp_group),
},
policy=policy,
target_key=attn_cls,
)
if self.pipeline_stage_manager is None:
self.append_or_create_method_replacement(
description={
"forward": get_llama_flash_attention_model_forward(
self.shard_config,
sp_mode=sp_mode,
sp_size=sp_size,
sp_group=sp_group,
),
},
policy=policy,
target_key=LlamaModel,
)
if self.shard_config.enable_tensor_parallelism:
assert (
num_q_heads % tp_size == 0
), f"The number of attention heads must be divisible by tensor parallel size."
if hasattr(self.model.config, "num_key_value_heads"):
assert (
num_kv_heads >= tp_size and num_kv_heads % tp_size == 0
), f"The number of key_value heads must be divisible by, and must not be less than tensor parallel size."
num_q_heads //= tp_size
decoder_attribute_replacement = {
"self_attn.hidden_size": self.model.config.hidden_size // tp_size,
"self_attn.num_heads": num_q_heads,
}
if getattr(self.model.config, "num_key_value_heads", False):
num_kv_heads //= tp_size
decoder_attribute_replacement["self_attn.num_key_value_heads"] = num_kv_heads
policy[LlamaDecoderLayer] = ModulePolicyDescription(
attribute_replacement=decoder_attribute_replacement,
sub_module_replacement=[
SubModuleReplacementDescription(
suffix="self_attn.q_proj",
target_module=Linear1D_Col,
kwargs=dict(seq_parallel_mode=sp_mode, fp8_communication=self.shard_config.fp8_communication),
),
SubModuleReplacementDescription(
suffix="self_attn.k_proj",
target_module=Linear1D_Col,
kwargs=dict(seq_parallel_mode=sp_mode, fp8_communication=self.shard_config.fp8_communication),
),
SubModuleReplacementDescription(
suffix="self_attn.v_proj",
target_module=Linear1D_Col,
kwargs=dict(seq_parallel_mode=sp_mode, fp8_communication=self.shard_config.fp8_communication),
),
SubModuleReplacementDescription(
suffix="self_attn.o_proj",
target_module=Linear1D_Row,
kwargs=dict(seq_parallel_mode=sp_mode, fp8_communication=self.shard_config.fp8_communication),
),
SubModuleReplacementDescription(
suffix="mlp.gate_proj",
target_module=Linear1D_Col,
kwargs=dict(seq_parallel_mode=sp_mode, fp8_communication=self.shard_config.fp8_communication),
),
SubModuleReplacementDescription(
suffix="mlp.up_proj",
target_module=Linear1D_Col,
kwargs=dict(seq_parallel_mode=sp_mode, fp8_communication=self.shard_config.fp8_communication),
),
SubModuleReplacementDescription(
suffix="mlp.down_proj",
target_module=Linear1D_Row,
kwargs=dict(seq_parallel_mode=sp_mode, fp8_communication=self.shard_config.fp8_communication),
),
],
)
if embedding_cls is not None:
self.append_or_create_submodule_replacement(
description=SubModuleReplacementDescription(
suffix="embed_tokens",
target_module=embedding_cls,
kwargs=(
{
"make_vocab_size_divisible_by": self.shard_config.make_vocab_size_divisible_by,
"fp8_communication": self.shard_config.fp8_communication,
}
if self.shard_config.enable_tensor_parallelism
else {"make_vocab_size_divisible_by": self.shard_config.make_vocab_size_divisible_by}
),
),
policy=policy,
target_key=LlamaModel,
)
# optimization configuration
self.append_or_create_submodule_replacement(
description=[
SubModuleReplacementDescription(
suffix="input_layernorm",
target_module=norm_cls,
kwargs={"sp_partial_derived": sp_partial_derived},
),
SubModuleReplacementDescription(
suffix="post_attention_layernorm",
target_module=norm_cls,
kwargs={"sp_partial_derived": sp_partial_derived},
),
],
policy=policy,
target_key=LlamaDecoderLayer,
)
self.append_or_create_submodule_replacement(
description=SubModuleReplacementDescription(
suffix="norm",
target_module=norm_cls,
kwargs={"sp_partial_derived": sp_partial_derived},
),
policy=policy,
target_key=LlamaModel,
)
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 is None:
return
stage_manager = self.pipeline_stage_manager
if self.model.__class__.__name__ == "LlamaModel":
module = self.model
else:
module = self.model.model
if stage_manager.is_interleave:
layers_per_stage = stage_manager.distribute_layers(len(module.layers))
stage_manager.stage_indices = stage_manager.get_stage_index(layers_per_stage)
method_replacement = {
"forward": partial(new_forward, stage_manager=stage_manager, shard_config=self.shard_config)
}
else:
layers_per_stage = stage_manager.distribute_layers(len(module.layers))
stage_index = stage_manager.get_stage_index(layers_per_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)
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 = []
if stage_manager.is_interleave:
assert stage_manager.num_model_chunks is not None
layers_per_stage = stage_manager.distribute_layers(len(module.layers))
stage_indices = stage_manager.get_stage_index(layers_per_stage)
if stage_manager.is_first_stage(ignore_chunk=True):
held_layers.append(module.embed_tokens)
for start_idx, end_idx in stage_indices:
held_layers.extend(module.layers[start_idx:end_idx])
if stage_manager.is_last_stage(ignore_chunk=True):
held_layers.append(module.norm)
else:
layers_per_stage = stage_manager.distribute_layers(len(module.layers))
if stage_manager.is_first_stage():
held_layers.append(module.embed_tokens)
start_idx, end_idx = stage_manager.get_stage_index(layers_per_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
self.is_causal = True
policy = super().module_policy()
if self.shard_config.enable_tensor_parallelism:
# add a new item for causal lm
new_item = {
LlamaForCausalLM: ModulePolicyDescription(
sub_module_replacement=[
SubModuleReplacementDescription(
suffix="lm_head",
target_module=VocabParallelLMHead1D,
kwargs={
"gather_output": not self.shard_config.parallel_output,
"make_vocab_size_divisible_by": self.shard_config.make_vocab_size_divisible_by,
"fp8_communication": self.shard_config.fp8_communication,
},
)
],
)
}
else:
new_item = {
LlamaForCausalLM: ModulePolicyDescription(
sub_module_replacement=[
SubModuleReplacementDescription(
suffix="lm_head",
target_module=PaddingLMHead,
kwargs={"make_vocab_size_divisible_by": self.shard_config.make_vocab_size_divisible_by},
)
],
)
}
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
)
elif self.shard_config.enable_tensor_parallelism or self.shard_config.enable_sequence_parallelism:
# Compute loss distributedly along the sequence dimension
new_item[LlamaForCausalLM].method_replacement = {
"forward": get_lm_forward_with_dist_cross_entropy(self.shard_config)
}
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(ignore_chunk=True):
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,
fp8_communication=self.shard_config.fp8_communication,
),
)
]
)
}
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(ignore_chunk=True):
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 []