Woosuk Kwon b411418ff0
[Chore] Remove Sampler from Model Code (#17084)
Signed-off-by: Woosuk Kwon <woosuk.kwon@berkeley.edu>
2025-04-24 02:49:33 -07:00

470 lines
18 KiB
Python

# SPDX-License-Identifier: Apache-2.0
from typing import Iterable, Optional, Set, Tuple, Union
import torch
import torch.nn as nn
from vllm.attention import Attention
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.fused_moe import FusedMoE
from vllm.model_executor.layers.linear import (QKVParallelLinear,
ReplicatedLinear,
RowParallelLinear)
from vllm.model_executor.layers.logits_processor import LogitsProcessor
from vllm.model_executor.layers.quantization import QuantizationConfig
from vllm.model_executor.layers.rotary_embedding import get_rope
from vllm.model_executor.layers.vocab_parallel_embedding import (
DEFAULT_VOCAB_PADDING_SIZE, ParallelLMHead, VocabParallelEmbedding)
from vllm.model_executor.model_loader.weight_utils import (
default_weight_loader, maybe_remap_kv_scale_name)
from vllm.model_executor.sampling_metadata import SamplingMetadata
from vllm.sequence import IntermediateTensors
from vllm.transformers_utils.configs.dbrx import DbrxConfig
from .interfaces import SupportsPP
from .utils import (is_pp_missing_parameter,
make_empty_intermediate_tensors_factory, make_layers,
maybe_prefix)
class DbrxRouter(nn.Module):
"""A Router implementation for DBRX that returns logits for each expert
per token.
"""
def __init__(
self,
config: DbrxConfig,
params_dtype: Optional[torch.dtype] = None,
):
super().__init__()
self.tp_size = get_tensor_model_parallel_world_size()
self.num_total_experts = config.ffn_config.moe_num_experts
self.d_model = config.d_model
self.layer = ReplicatedLinear(
self.d_model,
self.num_total_experts,
bias=False,
params_dtype=params_dtype,
quant_config=None,
)
def forward(self, hidden_states: torch.Tensor) -> torch.Tensor:
router_logits, _ = self.layer(hidden_states)
return router_logits
class DbrxExperts(FusedMoE):
def __init__(
self,
config: DbrxConfig,
quant_config: Optional[QuantizationConfig] = None,
params_dtype: Optional[torch.dtype] = None,
prefix: str = "",
):
super().__init__(
num_experts=config.ffn_config.moe_num_experts,
top_k=config.ffn_config.moe_top_k,
hidden_size=config.d_model,
intermediate_size=config.ffn_config.ffn_hidden_size,
params_dtype=params_dtype,
reduce_results=True,
renormalize=True,
quant_config=quant_config,
tp_size=get_tensor_model_parallel_world_size(),
prefix=prefix,
)
self.config = config
self.tp_size = get_tensor_model_parallel_world_size()
self.d_model = config.d_model
self.intermediate_size = (self.config.ffn_config.ffn_hidden_size //
self.tp_size)
# Define custom weight loader for dbrx model
def weight_loader(self, param: nn.Parameter, loaded_weight: torch.Tensor,
weight_name: str, param_name: str):
tp_rank = get_tensor_model_parallel_rank()
param_data = param.data
shard_size = self.intermediate_size
shard = slice(tp_rank * shard_size, (tp_rank + 1) * shard_size)
# DBRX uses GLU for each experts.
# GLU has 3 linear layers: w1, v1 and w2.
if weight_name.endswith("w1"):
if param_name.endswith("weight"):
loaded_weight = torch.reshape(
loaded_weight,
[-1, self.intermediate_size * self.tp_size, self.d_model],
)
param_data[:, 0:shard_size, :] = loaded_weight[:, shard, :]
elif param_name.endswith("weight_scale"):
param_data[:, 0] = loaded_weight
else:
param_data = loaded_weight
if weight_name.endswith("v1"):
if param_name.endswith("weight"):
loaded_weight = torch.reshape(
loaded_weight,
[-1, self.intermediate_size * self.tp_size, self.d_model],
)
param_data[:, shard_size:2 *
shard_size, :] = loaded_weight[:, shard, :]
elif param_name.endswith("weight_scale"):
param_data[:, 1] = loaded_weight
else:
param_data[:] = loaded_weight
if weight_name.endswith("w2"):
if param_name.endswith("weight"):
loaded_weight = torch.reshape(
loaded_weight,
[-1, self.intermediate_size * self.tp_size, self.d_model],
).transpose(1, 2)
param_data[:] = loaded_weight[:, :, shard]
else:
param_data[:] = loaded_weight
class DbrxMoE(nn.Module):
"""A tensor-parallel MoE implementation for DBRX.
Each expert's weights are sharded across all ranks and a fused MoE
kernel is used for the forward pass, and finally we reduce the outputs
across ranks.
"""
def __init__(
self,
config: DbrxConfig,
quant_config: Optional[QuantizationConfig] = None,
params_dtype: Optional[torch.dtype] = None,
prefix: str = "",
):
super().__init__()
self.d_model = config.d_model
if params_dtype is None:
params_dtype = torch.get_default_dtype()
self.params_dtype = params_dtype
self.router = DbrxRouter(config, self.params_dtype)
self.experts = DbrxExperts(config=config,
quant_config=quant_config,
params_dtype=self.params_dtype,
prefix=f"{prefix}.experts")
def forward(self, hidden_states: torch.Tensor) -> torch.Tensor:
orig_shape = hidden_states.shape
hidden_states = hidden_states.view(-1, self.d_model)
# router_logits: (num_tokens, n_experts)
router_logits = self.router(hidden_states)
final_hidden_states = self.experts(hidden_states, router_logits)
return final_hidden_states.view(orig_shape)
class DbrxAttention(nn.Module):
def __init__(
self,
config: DbrxConfig,
cache_config: Optional[CacheConfig] = None,
quant_config: Optional[QuantizationConfig] = 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.total_num_kv_heads = config.attn_config.kv_n_heads
self.clip_qkv = config.attn_config.clip_qkv
self.rope_theta = config.attn_config.rope_theta
self.max_position = config.max_seq_len
# pylint: disable=invalid-name
self.Wqkv = QKVParallelLinear(
self.d_model,
self.head_dim,
self.total_num_heads,
self.total_num_kv_heads,
bias=False,
quant_config=quant_config,
)
self.out_proj = RowParallelLinear(
self.d_model,
self.d_model,
bias=False,
quant_config=quant_config,
)
self.rotary_emb = get_rope(
self.head_dim,
rotary_dim=self.head_dim,
max_position=self.max_position,
base=int(self.rope_theta),
is_neox_style=True,
)
tp_world_size = get_tensor_model_parallel_world_size()
self.tp_size = tp_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
self.scaling = self.head_dim**-0.5
self.attn = Attention(self.num_heads,
self.head_dim,
self.scaling,
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:
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)
q, k = self.rotary_emb(position_ids, q, k)
attn_output = self.attn(q, k, v)
hidden_states, _ = self.out_proj(attn_output)
return hidden_states
class DbrxFusedNormAttention(nn.Module):
def __init__(
self,
config: DbrxConfig,
cache_config: Optional[CacheConfig] = None,
quant_config: Optional[QuantizationConfig] = None,
prefix: str = "",
):
super().__init__()
self.d_model = config.d_model
self.attn = DbrxAttention(config,
cache_config,
quant_config,
prefix=f"{prefix}.attn")
self.norm_1 = nn.LayerNorm(self.d_model)
self.norm_2 = nn.LayerNorm(self.d_model)
def forward(
self,
position_ids: torch.Tensor,
hidden_states: torch.Tensor,
) -> torch.Tensor:
residual = hidden_states
hidden_states = self.norm_1(hidden_states)
x = self.attn(
position_ids=position_ids,
hidden_states=hidden_states,
)
hidden_states = residual + x
residual = hidden_states
hidden_states = self.norm_2(hidden_states)
return hidden_states, residual
class DbrxBlock(nn.Module):
def __init__(
self,
config: DbrxConfig,
cache_config: Optional[CacheConfig] = None,
quant_config: Optional[QuantizationConfig] = None,
prefix: str = "",
):
super().__init__()
self.norm_attn_norm = DbrxFusedNormAttention(
config,
cache_config,
quant_config,
prefix=f"{prefix}.norm_attn_norm")
self.ffn = DbrxMoE(config, quant_config, prefix=f"{prefix}.ffn")
def forward(
self,
position_ids: torch.Tensor,
hidden_states: torch.Tensor,
) -> torch.Tensor:
hidden_states, residual = self.norm_attn_norm(
position_ids=position_ids,
hidden_states=hidden_states,
)
hidden_states = self.ffn(hidden_states)
hidden_states = hidden_states + residual
return hidden_states
class DbrxModel(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
self.wte = VocabParallelEmbedding(
config.vocab_size,
config.d_model,
)
self.start_layer, self.end_layer, self.blocks = make_layers(
config.n_layers,
lambda prefix: DbrxBlock(
config, cache_config, quant_config, prefix=prefix),
prefix=f"{prefix}.blocks",
)
self.norm_f = nn.LayerNorm(config.d_model, eps=1e-5)
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: Optional[IntermediateTensors],
inputs_embeds: Optional[torch.Tensor] = None,
) -> Union[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
hidden_states = intermediate_tensors["hidden_states"]
for block in 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
class DbrxForCausalLM(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
if config.tie_word_embeddings:
raise ValueError(
"tie_word_embeddings is not supported for Dbrx models.")
self.quant_config = quant_config
self.unpadded_vocab_size = config.vocab_size
self.transformer = DbrxModel(vllm_config=vllm_config,
prefix=maybe_prefix(
prefix, "transformer"))
self.lm_head = ParallelLMHead(
config.vocab_size,
config.d_model,
org_num_embeddings=config.vocab_size,
padding_size=DEFAULT_VOCAB_PADDING_SIZE,
quant_config=quant_config,
)
self.logits_processor = LogitsProcessor(self.unpadded_vocab_size,
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: Optional[IntermediateTensors] = None,
inputs_embeds: Optional[torch.Tensor] = None,
) -> Union[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,
sampling_metadata: SamplingMetadata,
) -> Optional[torch.Tensor]:
logits = self.logits_processor(self.lm_head, hidden_states,
sampling_metadata)
return logits
def load_weights(self, weights: Iterable[Tuple[str,
torch.Tensor]]) -> Set[str]:
expert_params_mapping = [(
"w13" if weight_name in ["w1", "v1"] else "w2",
f"mlp.{weight_name}",
) for weight_name in ["w1", "v1", "w2"]]
params_dict = dict(self.named_parameters(remove_duplicate=False))
loaded_params: Set[str] = set()
for name, loaded_weight in weights:
if (self.quant_config is not None and
(scale_name := self.quant_config.get_cache_scale(name))):
# Loading kv cache quantization scales
param = params_dict[scale_name]
weight_loader = getattr(param, "weight_loader",
default_weight_loader)
loaded_weight = (loaded_weight if loaded_weight.dim() == 0 else
loaded_weight[0])
weight_loader(param, loaded_weight)
loaded_params.add(scale_name)
continue
if name.endswith(("w1", "w2", "v1")):
name = name + "_weight"
for param_name, weight_name in expert_params_mapping:
if weight_name not in name:
continue
name = name.replace(weight_name, param_name)
if is_pp_missing_parameter(name, self):
continue
param = params_dict[name]
weight_loader = param.weight_loader
weight_loader(param, loaded_weight, weight_name, name)
break
else:
# Remapping the name of FP8 kv-scale.
name = maybe_remap_kv_scale_name(name, params_dict)
if name is None:
continue
if is_pp_missing_parameter(name, self):
continue
name = maybe_remap_kv_scale_name(name, params_dict)
if name is None:
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