preemo_text-generation-infe.../server/text_generation_server/models/custom_modeling/flash_rw_modeling.py

778 lines
23 KiB
Python

import os
import torch
import torch.distributed
from torch import nn
from transformers.modeling_utils import PreTrainedModel
from transformers.configuration_utils import PretrainedConfig
from typing import Optional
# Flash attention imports
import flash_attn_cuda
from text_generation_server.utils.layers import (
FastLinear,
TensorParallelRowLinear,
TensorParallelColumnLinear,
TensorParallelEmbedding,
FastLayerNorm,
PositionRotaryEmbedding,
)
class RWConfig(PretrainedConfig):
attribute_map = {
"num_hidden_layers": "n_layer",
"num_attention_heads": "n_head",
}
def __init__(
self,
model_type="RefinedWeb",
vocab_size=250880,
hidden_size=64,
n_layer=2,
n_head=8,
layer_norm_epsilon=1e-5,
initializer_range=0.02,
use_cache=True,
bos_token_id=1,
eos_token_id=2,
hidden_dropout=0.0,
attention_dropout=0.0,
n_head_kv=None,
multi_query=False,
alibi=False,
bias=False,
parallel_attn=False,
**kwargs,
):
if alibi:
raise NotImplementedError(
"alibi is not supported by this version of the model"
)
self.model_type = model_type
self.alibi = False
self.rotary = True
self.vocab_size = vocab_size
# Backward compatibility with n_embed kwarg
n_embed = kwargs.pop("n_embed", None)
self.hidden_size = hidden_size if n_embed is None else n_embed
self.n_layer = n_layer
self.n_head = n_head
self.layer_norm_epsilon = layer_norm_epsilon
self.initializer_range = initializer_range
self.use_cache = use_cache
self.hidden_dropout = hidden_dropout
self.attention_dropout = attention_dropout
self.bias = bias
self.parallel_attn = parallel_attn
self.bos_token_id = bos_token_id
self.eos_token_id = eos_token_id
if n_head_kv is not None:
self.n_head_kv = n_head_kv
else:
self.n_head_kv = 1 if multi_query else n_head
super().__init__(bos_token_id=bos_token_id, eos_token_id=eos_token_id, **kwargs)
class FlashRWAttention(torch.nn.Module):
def __init__(
self,
num_heads,
num_heads_kv,
hidden_size,
bias,
process_group=None,
reduce=True,
):
super().__init__()
self.num_heads = num_heads
self.num_heads_kv = num_heads_kv
self.hidden_size = hidden_size
self.head_size = hidden_size // num_heads
self.rotary_emb = PositionRotaryEmbedding(self.head_size, base=10000)
self.softmax_scale = self.head_size ** (-0.5)
if process_group is None:
self.query_key_value = FastLinear(
hidden_size,
self.head_size * (self.num_heads + 2 * self.num_heads_kv),
bias=bias,
)
self.dense = FastLinear(hidden_size, hidden_size, bias=bias)
else:
self.query_key_value = TensorParallelColumnLinear(
hidden_size,
self.head_size * (self.num_heads + 2 * self.num_heads_kv),
bias=bias,
process_group=process_group,
)
self.dense = TensorParallelRowLinear(
hidden_size,
hidden_size,
bias=bias,
process_group=process_group,
reduce=reduce,
)
self.num_heads = self.num_heads // process_group.size()
def forward(
self,
hidden_states,
cos,
sin,
cu_seqlens,
max_s,
layer_past,
layer_past_present_indices,
cu_seqlens_q,
):
qkv = self.query_key_value(hidden_states)
# Split query from key_value
query, kv = qkv.split(
[self.head_size * self.num_heads, 2 * self.head_size * self.num_heads_kv],
dim=1,
)
# Prepare query and key_value for indexing
query = query.view(-1, self.num_heads, self.head_size)
kv = kv.view(-1, 2, self.num_heads_kv, self.head_size)
# Inplace rotary
self.rotary_emb(query, cos, sin)
self.rotary_emb(kv[:, 0], cos, sin)
# Prefill
if layer_past_present_indices is None:
# Copy to layer past
layer_past[...] = kv
# Expand to query shape
kv = kv.expand(-1, 2, self.num_heads, self.head_size)
# output
attn_output = torch.empty_like(query)
# flash attention
flash_attn_cuda.fwd(
query,
kv[:, 0],
kv[:, 1],
attn_output,
cu_seqlens,
cu_seqlens,
max_s,
max_s,
0.0,
self.softmax_scale,
False,
True,
False,
0,
None,
)
# Decode
else:
# Add present to the layer_past tensor at the correct indices
layer_past[layer_past_present_indices] = kv
# Expand to query shape
kv = layer_past.expand(-1, 2, self.num_heads, self.head_size)
# output
attn_output = torch.empty_like(query)
# flash attention
flash_attn_cuda.fwd(
query,
kv[:, 0],
kv[:, 1],
attn_output,
cu_seqlens_q,
cu_seqlens,
1,
max_s,
0.0,
self.softmax_scale,
False,
False,
False,
0,
None,
)
return self.dense(attn_output.view(-1, self.num_heads * self.head_size))
class FlashRWLargeAttention(torch.nn.Module):
def __init__(
self,
num_heads,
num_heads_kv,
hidden_size,
bias,
process_group=None,
reduce=True,
):
super().__init__()
self.hidden_size = hidden_size
self.head_size = hidden_size // num_heads
self.rotary_emb = PositionRotaryEmbedding(self.head_size, base=10000)
self.softmax_scale = self.head_size ** (-0.5)
self.num_groups = num_heads // (num_heads_kv * 2)
self.num_heads = num_heads // self.num_groups
self.num_heads_kv = num_heads_kv // self.num_groups
if process_group is None:
self.query_key_value = FastLinear(
hidden_size,
self.num_groups
* self.head_size
* (self.num_heads + 2 * self.num_heads_kv),
bias=bias,
)
self.dense = FastLinear(hidden_size, hidden_size, bias=bias)
else:
if process_group.size() > self.num_groups:
raise NotImplementedError(
f"Tensor Parallelism is not implemented for world_size > n groups"
)
self.query_key_value = TensorParallelColumnLinear(
hidden_size,
self.num_groups
* self.head_size
* (self.num_heads + 2 * self.num_heads_kv),
bias=bias,
process_group=process_group,
)
self.dense = TensorParallelRowLinear(
hidden_size,
hidden_size,
bias=bias,
process_group=process_group,
reduce=reduce,
)
self.num_groups = self.num_groups // process_group.size()
def forward(
self,
hidden_states,
cos,
sin,
cu_seqlens,
max_s,
layer_past,
layer_past_present_indices,
cu_seqlens_q,
):
qkv = self.query_key_value(hidden_states)
qkv = qkv.view(-1, self.num_groups, self.num_heads + 2, self.head_size)
# Split on group dimension
query, kv = qkv.split(
[self.num_heads, 2],
dim=2,
)
# Merge groups and heads
query = query.reshape(-1, self.num_groups * self.num_heads, self.head_size)
# Inplace rotary
self.rotary_emb(query, cos, sin)
self.rotary_emb(kv[:, :, 0], cos, sin)
# Prefill
if layer_past_present_indices is None:
# Copy to layer past
layer_past[...] = kv
# Expand to query shape
kv = (
kv.unsqueeze(2)
.expand(-1, self.num_groups, self.num_heads, 2, self.head_size)
.reshape(-1, self.num_groups * self.num_heads, 2, self.head_size)
)
# output
attn_output = torch.empty_like(query)
# flash attention
flash_attn_cuda.fwd(
query,
kv[:, :, 0],
kv[:, :, 1],
attn_output,
cu_seqlens,
cu_seqlens,
max_s,
max_s,
0.0,
self.softmax_scale,
False,
True,
False,
0,
None,
)
# Decode
else:
# Add present to the layer_past tensor at the correct indices
layer_past[layer_past_present_indices] = kv
# Expand to query shape
kv = (
layer_past.unsqueeze(2)
.expand(-1, self.num_groups, self.num_heads, 2, self.head_size)
.reshape(-1, self.num_groups * self.num_heads, 2, self.head_size)
)
# output
attn_output = torch.empty_like(query)
# flash attention
flash_attn_cuda.fwd(
query,
kv[:, :, 0],
kv[:, :, 1],
attn_output,
cu_seqlens_q,
cu_seqlens,
1,
max_s,
0.0,
self.softmax_scale,
False,
False,
False,
0,
None,
)
return self.dense(
attn_output.view(-1, self.num_groups * self.num_heads * self.head_size)
)
class FlashMLP(nn.Module):
def __init__(self, hidden_size, bias, process_group=None, reduce=True):
super().__init__()
self.act = torch.nn.functional.gelu
if process_group is None:
self.dense_h_to_4h = FastLinear(hidden_size, 4 * hidden_size, bias=bias)
self.dense_4h_to_h = FastLinear(4 * hidden_size, hidden_size, bias=bias)
else:
self.dense_h_to_4h = TensorParallelColumnLinear(
hidden_size,
4 * hidden_size,
bias=bias,
process_group=process_group,
)
self.dense_4h_to_h = TensorParallelRowLinear(
4 * hidden_size,
hidden_size,
bias=bias,
process_group=process_group,
reduce=reduce,
)
self.process_group = process_group
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 FlashRWLayer(nn.Module):
def __init__(
self,
num_heads,
num_heads_kv,
hidden_size,
bias,
layer_norm_eps,
parallel_attn,
process_group=None,
):
super().__init__()
self.parallel_attn = parallel_attn
self.input_layernorm = FastLayerNorm(hidden_size, eps=layer_norm_eps)
self.self_attention = FlashRWAttention(
num_heads,
num_heads_kv,
hidden_size,
bias,
process_group=process_group,
reduce=False,
)
self.post_attention_layernorm = (
FastLayerNorm(hidden_size, eps=layer_norm_eps)
if not parallel_attn
else None
)
self.mlp = FlashMLP(
hidden_size, bias, process_group=process_group, reduce=False
)
self.process_group = process_group
def forward(
self,
hidden_states,
residual,
cos,
sin,
cu_seqlens,
max_s,
layer_past,
layer_past_present_indices,
cu_seqlens_q,
):
if self.parallel_attn:
ln_hidden_states, residual = self.input_layernorm(hidden_states, residual)
attn_output = self.self_attention(
ln_hidden_states,
cos,
sin,
cu_seqlens,
max_s,
layer_past,
layer_past_present_indices,
cu_seqlens_q,
)
mlp_output = self.mlp(ln_hidden_states)
intermediate = mlp_output + attn_output
# Only reduce once and after the addition instead of once per layer
if self.process_group is not None:
torch.distributed.all_reduce(intermediate, group=self.process_group)
return intermediate, residual
else:
hidden_states, residual = self.input_layernorm(hidden_states, residual)
hidden_states = self.self_attention(
hidden_states,
cos,
sin,
cu_seqlens,
max_s,
layer_past,
layer_past_present_indices,
cu_seqlens_q,
)
hidden_states, residual = self.post_attention_layernorm(
hidden_states, residual
)
mlp_output = self.mlp(hidden_states)
return mlp_output, residual
class FlashRWLargeLayer(nn.Module):
def __init__(
self,
num_heads,
num_heads_kv,
hidden_size,
bias,
layer_norm_eps,
process_group=None,
):
super().__init__()
self.ln_attn = FastLayerNorm(hidden_size, eps=layer_norm_eps)
self.ln_mlp = FastLayerNorm(hidden_size, eps=layer_norm_eps)
self.self_attention = FlashRWLargeAttention(
num_heads,
num_heads_kv,
hidden_size,
bias,
process_group=process_group,
reduce=False,
)
self.mlp = FlashMLP(
hidden_size, bias, process_group=process_group, reduce=False
)
self.process_group = process_group
def forward(
self,
hidden_states,
residual,
cos,
sin,
cu_seqlens,
max_s,
layer_past,
layer_past_present_indices,
cu_seqlens_q,
):
ln_attn, residual = self.ln_attn(hidden_states, residual)
ln_mlp, _ = self.ln_mlp(residual)
# Self attention.
attn_output = self.self_attention(
ln_attn,
cos,
sin,
cu_seqlens,
max_s,
layer_past,
layer_past_present_indices,
cu_seqlens_q,
)
# MLP.
mlp_output = self.mlp(ln_mlp)
intermediate = attn_output + mlp_output
# Only reduce once and after the addition instead of once per layer
if self.process_group is not None:
torch.distributed.all_reduce(intermediate, group=self.process_group)
return intermediate, residual
class FlashRWPreTrainedModel(PreTrainedModel):
config_class = RWConfig
class FlashRWModel(FlashRWPreTrainedModel):
def __init__(self, config, process_group=None):
super().__init__(config)
self.config = config
self.tp_embeddings = False
if process_group is not None:
self.tp_rank = process_group.rank()
self.tp_world_size = process_group.size()
if config.vocab_size % self.tp_world_size == 0:
self.tp_embeddings = True
if self.tp_embeddings:
self.word_embeddings = TensorParallelEmbedding(
config.vocab_size, config.hidden_size, process_group=process_group
)
else:
self.word_embeddings = nn.Embedding(config.vocab_size, config.hidden_size)
if config.model_type == "RefinedWebModel":
self.h = nn.ModuleList(
[
FlashRWLayer(
config.n_head,
config.n_head_kv,
config.hidden_size,
config.bias,
config.layer_norm_epsilon,
config.parallel_attn,
process_group,
)
for _ in range(config.num_hidden_layers)
]
)
self.cache_size = (
2,
self.h[0].self_attention.num_heads_kv,
self.h[0].self_attention.head_size,
)
elif config.model_type == "RefinedWeb":
self.h = nn.ModuleList(
[
FlashRWLargeLayer(
config.n_head,
config.n_head_kv,
config.hidden_size,
config.bias,
config.layer_norm_epsilon,
process_group,
)
for _ in range(config.num_hidden_layers)
]
)
self.cache_size = (
self.h[0].self_attention.num_groups,
2,
self.h[0].self_attention.head_size,
)
else:
raise NotImplementedError(
f"model_type {config.model_type} is not supported."
)
self.ln_f = FastLayerNorm(config.hidden_size, eps=config.layer_norm_epsilon)
self.head_size = self.h[0].self_attention.head_size
def post_load_weights(self, quantize: Optional[str] = None):
if isinstance(self.word_embeddings, TensorParallelEmbedding):
self.word_embeddings.add_null_idx()
for layer in self.h:
layer: FlashRWLayer
layer.self_attention.query_key_value.prepare_weights(quantize)
layer.self_attention.dense.prepare_weights(quantize)
layer.mlp.dense_h_to_4h.prepare_weights(quantize)
layer.mlp.dense_4h_to_h.prepare_weights(quantize)
@classmethod
def from_pretrained(cls, pretrained_model_name_or_path, *model_args, **kwargs):
# Pop here as we will replace the layer in our own logic and don't want from_pretrained
# to do it for us
load_in_8bit = kwargs.pop("load_in_8bit", False)
model = super(FlashRWModel, cls).from_pretrained(
pretrained_model_name_or_path, load_in_8bit=False, *model_args, **kwargs
)
model.post_load_weights("bitsandbytes" if load_in_8bit else None)
return model
def forward(
self,
input_ids,
position_ids,
cu_seqlens,
cu_seqlens_q,
max_s,
past_key_values=None,
pre_allocate_past_size: Optional[int] = None,
):
hidden_states = self.word_embeddings(input_ids)
# Prefill
if past_key_values is None:
# Create past tensor
past_key_values = hidden_states.new_empty(
(
len(self.h),
len(hidden_states)
if pre_allocate_past_size is None
else pre_allocate_past_size,
*self.cache_size,
)
)
layer_past_present_indices = None
slice_past_index = len(hidden_states)
# Decode
else:
# Create indices from cumulative sequence lengths
layer_past_present_indices = cu_seqlens[1:] - 1
slice_past_index = None
# Get rotary cos and sin for this forward
# Avoid to index in each layer
cos, sin = self.h[0].self_attention.rotary_emb.get_cos_sin(
position_ids, max_s, hidden_states.dtype
)
residual = None
for i, layer in enumerate(self.h):
# We added padding that we now need to slice
layer_past_key_values = (
past_key_values[i]
if slice_past_index is None
else past_key_values[i, :slice_past_index]
)
hidden_states, residual = layer(
hidden_states,
residual,
cos,
sin,
cu_seqlens,
max_s,
layer_past_key_values,
layer_past_present_indices,
cu_seqlens_q,
)
hidden_states, _ = self.ln_f(hidden_states, residual)
return hidden_states, past_key_values
class FlashRWForCausalLM(FlashRWPreTrainedModel):
def __init__(self, config, process_group=None):
super().__init__(config)
self.process_group = process_group
if self.process_group is not None:
self.world_size = self.process_group.size()
else:
self.world_size = 1
self.transformer = FlashRWModel(config, process_group)
if self.transformer.tp_embeddings:
self.lm_head = FastLinear(
config.hidden_size,
config.vocab_size // process_group.size(),
bias=False,
)
else:
self.lm_head = FastLinear(config.hidden_size, config.vocab_size, bias=False)
def post_load_weights(self, quantize: Optional[str] = None):
self.transformer.post_load_weights(quantize)
self.lm_head.prepare_weights()
@classmethod
def from_pretrained(cls, pretrained_model_name_or_path, *model_args, **kwargs):
# Pop here as we will replace the layer in our own logic and don't want from_pretrained
# to do it for us
load_in_8bit = kwargs.pop("load_in_8bit", False)
model = super(FlashRWForCausalLM, cls).from_pretrained(
pretrained_model_name_or_path, load_in_8bit=False, *model_args, **kwargs
)
model.post_load_weights("bitsandbytes" if load_in_8bit else None)
return model
def forward(
self,
input_ids,
position_ids,
cu_seqlens,
cu_seqlens_q,
max_s,
past_key_values: Optional[torch.Tensor] = None,
pre_allocate_past_size: Optional[int] = None,
lm_head_indices: Optional[torch.Tensor] = None,
):
hidden_states, present = self.transformer(
input_ids,
position_ids,
cu_seqlens,
cu_seqlens_q,
max_s,
past_key_values,
pre_allocate_past_size,
)
if lm_head_indices is not None:
hidden_states = hidden_states[lm_head_indices]
logits = self.lm_head(hidden_states)
if self.transformer.tp_embeddings:
# Logits are sharded, so we need to gather them
world_logits = [torch.empty_like(logits) for _ in range(self.world_size)]
torch.distributed.all_gather(world_logits, logits, group=self.process_group)
world_logits = torch.cat(world_logits, dim=1)
return world_logits, present
return logits, present