254 lines
11 KiB
Python

# coding=utf-8
# Adapted from https://github.com/huggingface/transformers/blob/v4.28.0/src/transformers/models/gpt_neox/modeling_gpt_neox.py
# Copyright 2023 The CacheFlow team.
# Copyright 2022 EleutherAI The HuggingFace Inc. team. All rights reserved.
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
"""Inference-only GPT-NeoX model compatible with HuggingFace weights.
The input of the model is flattened to a 1D tensor of tokens. The model uses
InputMetadata to extract the original 2D shape of the input.
"""
from typing import Dict, List, Optional, Tuple
import torch
from torch import nn
from transformers import GPTNeoXConfig
from cacheflow.model_executor.input_metadata import InputMetadata
from cacheflow.model_executor.layers.attention import GPTNeoXCacheFlowAttention
from cacheflow.model_executor.layers.sampler import Sampler
from cacheflow.model_executor.weight_utils import (hf_model_weights_iterator,
load_tensor_parallel_weights)
from cacheflow.model_executor.parallel_utils.parallel_state import (
get_tensor_model_parallel_rank, get_tensor_model_parallel_world_size)
from cacheflow.model_executor.parallel_utils.tensor_parallel import (
VocabParallelEmbedding, ColumnParallelLinear, RowParallelLinear)
from cacheflow.sequence import SequenceOutputs
KVCache = Tuple[torch.Tensor, torch.Tensor]
class GPTNeoXAttention(nn.Module):
def __init__(self, config: GPTNeoXConfig):
super().__init__()
self.total_num_heads = config.num_attention_heads
self.hidden_size = config.hidden_size
self.head_size = self.hidden_size // self.total_num_heads
tensor_model_parallel_world_size = get_tensor_model_parallel_world_size()
assert self.total_num_heads % tensor_model_parallel_world_size == 0
self.num_heads = self.total_num_heads // tensor_model_parallel_world_size
self.query_key_value = ColumnParallelLinear(config.hidden_size,
3 * config.hidden_size,
gather_output=False,
perform_initialization=False)
self.dense = RowParallelLinear(config.hidden_size, config.hidden_size,
input_is_parallel=True,
perform_initialization=False)
scaling = self.head_size ** -0.5
rotary_dim = int(self.head_size * config.rotary_pct)
assert rotary_dim % 2 == 0
self.attn = GPTNeoXCacheFlowAttention(self.num_heads, self.head_size,
scaling, rotary_dim)
def forward(
self,
position_ids: torch.LongTensor,
hidden_states: torch.Tensor,
kv_cache: KVCache,
input_metadata: InputMetadata,
cache_event: Optional[torch.cuda.Event],
) -> torch.Tensor:
qkv, _ = self.query_key_value(hidden_states)
q, k, v = qkv.chunk(chunks=3, dim=-1)
k_cache, v_cache = kv_cache
attn_output = self.attn(
position_ids, q, k, v, k_cache, v_cache, input_metadata, cache_event)
output, _ = self.dense(attn_output)
return output
class GPTNeoXMLP(nn.Module):
def __init__(self, config: GPTNeoXConfig):
super().__init__()
self.dense_h_to_4h = ColumnParallelLinear(config.hidden_size,
config.intermediate_size,
gather_output=False,
perform_initialization=False)
self.dense_4h_to_h = RowParallelLinear(config.intermediate_size, config.hidden_size,
input_is_parallel=True,
perform_initialization=False)
if config.hidden_act != 'gelu':
raise ValueError(f'Unsupported activation: {config.hidden_act}. '
'Only gelu is supported for now.')
self.act = torch.nn.GELU()
def forward(self, hidden_states):
hidden_states, _ = self.dense_h_to_4h(hidden_states)
hidden_states = self.act(hidden_states)
hidden_states, _ = self.dense_4h_to_h(hidden_states)
return hidden_states
class GPTNeoXLayer(nn.Module):
def __init__(self, config: GPTNeoXConfig):
super().__init__()
self.use_parallel_residual = config.use_parallel_residual
self.input_layernorm = nn.LayerNorm(config.hidden_size, eps=config.layer_norm_eps)
self.post_attention_layernorm = nn.LayerNorm(config.hidden_size, eps=config.layer_norm_eps)
self.attention = GPTNeoXAttention(config)
self.mlp = GPTNeoXMLP(config)
def forward(
self,
position_ids: torch.LongTensor,
hidden_states: torch.Tensor,
kv_cache: KVCache,
input_metadata: InputMetadata,
cache_event: Optional[torch.cuda.Event],
) -> torch.Tensor:
attn_input = self.input_layernorm(hidden_states)
attn_output = self.attention(
position_ids=position_ids,
hidden_states=attn_input,
kv_cache=kv_cache,
input_metadata=input_metadata,
cache_event=cache_event,
)
if self.use_parallel_residual:
# pseudocode:
# x = x + attn(ln1(x)) + mlp(ln2(x))
mlp_input = self.post_attention_layernorm(hidden_states)
mlp_output = self.mlp(mlp_input)
hidden_states = mlp_output + attn_output + hidden_states
else:
# pseudocode:
# x = x + attn(ln1(x))
# x = x + mlp(ln2(x))
attn_output = attn_output + hidden_states
mlp_input = self.post_attention_layernorm(attn_output)
mlp_output = self.mlp(mlp_input)
hidden_states = mlp_output + attn_output
return hidden_states
class GPTNeoXModel(nn.Module):
def __init__(self, config: GPTNeoXConfig):
super().__init__()
self.config = config
self.embed_in = VocabParallelEmbedding(config.vocab_size, config.hidden_size,
perform_initialization=False)
self.layers = nn.ModuleList([GPTNeoXLayer(config) for _ in range(config.num_hidden_layers)])
self.final_layer_norm = nn.LayerNorm(config.hidden_size, eps=config.layer_norm_eps)
def forward(
self,
input_ids: torch.LongTensor,
position_ids: torch.LongTensor,
kv_caches: List[KVCache],
input_metadata: InputMetadata,
cache_events: Optional[List[torch.cuda.Event]],
) -> torch.Tensor:
hidden_states = self.embed_in(input_ids)
for i in range(len(self.layers)):
if cache_events is None:
cache_event = None
else:
cache_event = cache_events[i]
layer = self.layers[i]
hidden_states = layer(
position_ids,
hidden_states,
kv_caches[i],
input_metadata,
cache_event,
)
hidden_states = self.final_layer_norm(hidden_states)
return hidden_states
class GPTNeoXForCausalLM(nn.Module):
def __init__(self, config):
super().__init__()
self.config = config
self.gpt_neox = GPTNeoXModel(config)
self.embed_out = ColumnParallelLinear(config.hidden_size, config.vocab_size,
bias=False, gather_output=False,
perform_initialization=False)
self.sampler = Sampler(config.vocab_size)
def forward(
self,
input_ids: torch.LongTensor,
positions: torch.LongTensor,
kv_caches: List[KVCache],
input_metadata: InputMetadata,
cache_events: Optional[List[torch.cuda.Event]],
) -> Dict[int, SequenceOutputs]:
hidden_states = self.gpt_neox(
input_ids, positions, kv_caches, input_metadata, cache_events)
next_tokens = self.sampler(
self.embed_out.weight, hidden_states, input_metadata)
return next_tokens
_column_parallel_weights = ["embed_in.weight", "embed_out.weight", "dense_h_to_4h.weight", "dense_h_to_4h.bias"]
_row_parallel_weights = ["dense.weight", "dense_4h_to_h.weight"]
def load_weights(self, model_name_or_path: str,
cache_dir: Optional[str] = None,
use_np_cache: bool = False):
tensor_model_parallel_rank = get_tensor_model_parallel_rank()
state_dict = self.state_dict()
for name, loaded_weight in hf_model_weights_iterator(
model_name_or_path, cache_dir, use_np_cache):
if ("attention.bias" in name or "attention.masked_bias" in name
or "rotary_emb.inv_freq" in name):
continue
param = state_dict[name]
if "query_key_value" in name:
# NOTE(woosuk): GPT-NeoX's fused QKV has the shape of
# [num_heads * 3 * head_size, hidden_size], while the
# required shape is [3 * num_heads * head_size, hidden_size].
# Thus, we need weight conversion.
shard_size = param.shape[0]
loaded_weight = loaded_weight[shard_size * tensor_model_parallel_rank
:shard_size * (tensor_model_parallel_rank + 1)]
num_heads = self.config.num_attention_heads
hidden_size = self.config.hidden_size
head_size = hidden_size // num_heads
if 'query_key_value.weight' in name:
loaded_weight = loaded_weight.view(-1, 3, head_size, hidden_size)
loaded_weight = loaded_weight.transpose(0, 1)
loaded_weight = loaded_weight.reshape(-1, hidden_size)
elif 'query_key_value.bias' in name:
loaded_weight = loaded_weight.view(-1, 3, head_size)
loaded_weight = loaded_weight.transpose(0, 1)
loaded_weight = loaded_weight.reshape(-1)
else:
raise ValueError(f"Unexpected weight name: {name}")
load_tensor_parallel_weights(param, loaded_weight, name,
self._column_parallel_weights,
self._row_parallel_weights,
tensor_model_parallel_rank)