Harry Mellor 8fcaaf6a16
Update Optional[x] -> x | None and Union[x, y] to x | y (#26633)
Signed-off-by: Harry Mellor <19981378+hmellor@users.noreply.github.com>
2025-10-12 09:51:31 -07:00

331 lines
12 KiB
Python

# SPDX-License-Identifier: Apache-2.0
# SPDX-FileCopyrightText: Copyright contributors to the vLLM project
# Adapted from https://huggingface.co/mosaicml/mpt-7b/tree/main
import math
from collections.abc import Iterable
from itertools import islice
import torch
import torch.nn as nn
from transformers import MptConfig
from vllm.attention import Attention
from vllm.compilation.decorators import support_torch_compile
from vllm.config import CacheConfig, VllmConfig
from vllm.distributed import (
get_pp_group,
get_tensor_model_parallel_rank,
get_tensor_model_parallel_world_size,
)
from vllm.model_executor.layers.activation import get_act_fn
from vllm.model_executor.layers.linear import (
ColumnParallelLinear,
QKVParallelLinear,
RowParallelLinear,
)
from vllm.model_executor.layers.logits_processor import LogitsProcessor
from vllm.model_executor.layers.quantization import QuantizationConfig
from vllm.model_executor.layers.vocab_parallel_embedding import VocabParallelEmbedding
from vllm.model_executor.model_loader.weight_utils import default_weight_loader
from vllm.sequence import IntermediateTensors
from .interfaces import SupportsPP
from .utils import (
AutoWeightsLoader,
is_pp_missing_parameter,
make_empty_intermediate_tensors_factory,
make_layers,
maybe_prefix,
)
def _get_alibi_slopes(
total_num_heads: int,
alibi_bias_max: int,
) -> torch.Tensor:
next_power_of_2 = 2 ** math.ceil(math.log2(total_num_heads))
m = torch.arange(1, next_power_of_2 + 1, dtype=torch.float32)
m = m.mul(alibi_bias_max / next_power_of_2)
slopes = 1.0 / torch.pow(2, m)
if next_power_of_2 != total_num_heads:
slopes = torch.concat([slopes[1::2], slopes[::2]])[:total_num_heads]
return slopes
class MPTAttention(nn.Module):
def __init__(
self,
config: MptConfig,
cache_config: CacheConfig | None = None,
quant_config: QuantizationConfig | None = None,
prefix: str = "",
):
super().__init__()
self.d_model = config.d_model
self.total_num_heads = config.n_heads
self.head_dim = self.d_model // self.total_num_heads
self.clip_qkv = config.attn_config.clip_qkv
self.qk_ln = config.attn_config.qk_ln
self.alibi_bias_max = config.attn_config.alibi_bias_max
if "kv_n_heads" in config.attn_config:
self.total_num_kv_heads = config.attn_config.kv_n_heads
else:
self.total_num_kv_heads = self.total_num_heads
assert not config.attn_config.prefix_lm
assert config.attn_config.alibi
# pylint: disable=invalid-name
self.Wqkv = QKVParallelLinear(
self.d_model,
self.d_model // self.total_num_heads,
self.total_num_heads,
self.total_num_kv_heads,
bias=not config.no_bias,
quant_config=quant_config,
)
if self.qk_ln:
self.q_ln = nn.LayerNorm(self.d_model)
self.k_ln = nn.LayerNorm(self.d_model)
self.out_proj = RowParallelLinear(
self.d_model,
self.d_model,
bias=not config.no_bias,
quant_config=quant_config,
)
tp_world_size = get_tensor_model_parallel_world_size()
assert self.total_num_heads % tp_world_size == 0
self.num_heads = self.total_num_heads // tp_world_size
if self.total_num_kv_heads >= tp_world_size:
# Number of KV heads is greater than TP size, so we partition
# the KV heads across multiple tensor parallel GPUs.
assert self.total_num_kv_heads % tp_world_size == 0
else:
# Number of KV heads is less than TP size, so we replicate
# the KV heads across multiple tensor parallel GPUs.
assert tp_world_size % self.total_num_kv_heads == 0
self.num_kv_heads = max(1, self.total_num_kv_heads // tp_world_size)
self.q_size = self.num_heads * self.head_dim
self.kv_size = self.num_kv_heads * self.head_dim
# Create the alibi slopes and slice them.
tp_rank = get_tensor_model_parallel_rank()
head_start = tp_rank * self.num_heads
head_end = (tp_rank + 1) * self.num_heads
alibi_slopes = _get_alibi_slopes(self.total_num_heads, self.alibi_bias_max)
alibi_slopes = alibi_slopes[head_start:head_end].tolist()
self.head_dim = self.d_model // self.total_num_heads
scaling = self.head_dim**-0.5
self.attn = Attention(
self.num_heads,
self.head_dim,
scaling,
alibi_slopes=alibi_slopes,
num_kv_heads=self.num_kv_heads,
cache_config=cache_config,
quant_config=quant_config,
prefix=f"{prefix}.attn",
)
def forward(
self,
position_ids: torch.Tensor,
hidden_states: torch.Tensor,
) -> torch.Tensor:
del position_ids # unused.
qkv, _ = self.Wqkv(hidden_states)
if self.clip_qkv is not None:
qkv.clamp_(min=-self.clip_qkv, max=self.clip_qkv)
q, k, v = qkv.split([self.q_size, self.kv_size, self.kv_size], dim=-1)
if self.qk_ln:
q = self.q_ln(q)
k = self.k_ln(k)
attn_output = self.attn(q, k, v)
output, _ = self.out_proj(attn_output)
return output
class MPTMLP(nn.Module):
def __init__(
self,
config: MptConfig,
quant_config: QuantizationConfig | None = None,
):
super().__init__()
hidden_size = config.d_model
expansion_ratio = config.expansion_ratio
intermediate_size = expansion_ratio * hidden_size
self.up_proj = ColumnParallelLinear(
hidden_size,
intermediate_size,
bias=not config.no_bias,
quant_config=quant_config,
)
self.act = get_act_fn("gelu")
self.down_proj = RowParallelLinear(
intermediate_size,
hidden_size,
bias=not config.no_bias,
quant_config=quant_config,
)
def forward(self, x: torch.Tensor) -> torch.Tensor:
x, _ = self.up_proj(x)
x = self.act(x)
x, _ = self.down_proj(x)
return x
class MPTBlock(nn.Module):
def __init__(
self,
config: MptConfig,
cache_config: CacheConfig | None = None,
quant_config: QuantizationConfig | None = None,
prefix: str = "",
):
super().__init__()
hidden_size = config.d_model
self.norm_1 = nn.LayerNorm(hidden_size)
self.attn = MPTAttention(
config, cache_config, quant_config, prefix=f"{prefix}.attn"
)
self.norm_2 = nn.LayerNorm(hidden_size)
self.ffn = MPTMLP(config, quant_config)
def forward(
self,
position_ids: torch.Tensor,
hidden_states: torch.Tensor,
) -> torch.Tensor:
x = self.norm_1(hidden_states)
x = self.attn(
position_ids=position_ids,
hidden_states=x,
)
hidden_states = hidden_states + x
x = self.norm_2(hidden_states)
x = self.ffn(x)
hidden_states = hidden_states + x
return hidden_states
@support_torch_compile
class MPTModel(nn.Module):
def __init__(self, *, vllm_config: VllmConfig, prefix: str = ""):
super().__init__()
config = vllm_config.model_config.hf_config
cache_config = vllm_config.cache_config
quant_config = vllm_config.quant_config
assert config.embedding_fraction == 1.0
assert config.norm_type == "low_precision_layernorm"
self.wte = VocabParallelEmbedding(
config.vocab_size,
config.d_model,
)
self.start_layer, self.end_layer, self.blocks = make_layers(
config.n_layers,
lambda prefix: MPTBlock(config, cache_config, quant_config, prefix=prefix),
prefix=f"{prefix}.blocks",
)
self.norm_f = nn.LayerNorm(config.d_model)
if config.no_bias:
for module in self.modules():
if hasattr(module, "bias") and isinstance(module.bias, nn.Parameter):
# Remove the bias term in Linear and LayerNorm.
module.register_parameter("bias", None)
self.make_empty_intermediate_tensors = make_empty_intermediate_tensors_factory(
["hidden_states"], config.d_model
)
def get_input_embeddings(self, input_ids: torch.Tensor) -> torch.Tensor:
return self.wte(input_ids)
def forward(
self,
input_ids: torch.Tensor,
position_ids: torch.Tensor,
intermediate_tensors: IntermediateTensors | None,
inputs_embeds: torch.Tensor | None = None,
) -> torch.Tensor | IntermediateTensors:
if get_pp_group().is_first_rank:
if inputs_embeds is not None:
hidden_states = inputs_embeds
else:
hidden_states = self.get_input_embeddings(input_ids)
else:
assert intermediate_tensors is not None
hidden_states = intermediate_tensors["hidden_states"]
for block in islice(self.blocks, self.start_layer, self.end_layer):
hidden_states = block(position_ids, hidden_states)
if not get_pp_group().is_last_rank:
return IntermediateTensors({"hidden_states": hidden_states})
hidden_states = self.norm_f(hidden_states)
return hidden_states
def load_weights(self, weights: Iterable[tuple[str, torch.Tensor]]) -> set[str]:
params_dict = dict(self.named_parameters(remove_duplicate=False))
loaded_params: set[str] = set()
for name, loaded_weight in weights:
# Skip loading extra bias for GPTQ models.
if name.endswith(".bias") and name not in params_dict:
continue
if is_pp_missing_parameter(name, self):
continue
param = params_dict[name]
weight_loader = getattr(param, "weight_loader", default_weight_loader)
weight_loader(param, loaded_weight)
loaded_params.add(name)
return loaded_params
class MPTForCausalLM(nn.Module, SupportsPP):
def __init__(self, *, vllm_config: VllmConfig, prefix: str = ""):
super().__init__()
config = vllm_config.model_config.hf_config
quant_config = vllm_config.quant_config
self.config = config
assert config.tie_word_embeddings
self.quant_config = quant_config
self.transformer = MPTModel(
vllm_config=vllm_config, prefix=maybe_prefix(prefix, "transformer")
)
self.lm_head = self.transformer.wte
self.logits_processor = LogitsProcessor(config.vocab_size)
self.make_empty_intermediate_tensors = (
self.transformer.make_empty_intermediate_tensors
)
def get_input_embeddings(self, input_ids: torch.Tensor) -> torch.Tensor:
return self.transformer.get_input_embeddings(input_ids)
def forward(
self,
input_ids: torch.Tensor,
positions: torch.Tensor,
intermediate_tensors: IntermediateTensors | None = None,
inputs_embeds: torch.Tensor | None = None,
) -> torch.Tensor | IntermediateTensors:
hidden_states = self.transformer(
input_ids, positions, intermediate_tensors, inputs_embeds
)
return hidden_states
def compute_logits(
self,
hidden_states: torch.Tensor,
) -> torch.Tensor | None:
logits = self.logits_processor(self.lm_head, hidden_states)
return logits
def load_weights(self, weights: Iterable[tuple[str, torch.Tensor]]) -> set[str]:
loader = AutoWeightsLoader(self)
return loader.load_weights(weights)