2023-05-09 15:30:12 -07:00

232 lines
9.9 KiB
Python

"""1D GPT-NeoX model compatible with HuggingFace weights."""
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(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)