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Python

# SPDX-License-Identifier: Apache-2.0
# SPDX-FileCopyrightText: Copyright contributors to the vLLM project
from collections.abc import Iterable
from typing import Optional
import torch
import torch.nn as nn
from transformers import LlamaConfig
from vllm.compilation.decorators import support_torch_compile
from vllm.config import VllmConfig
from vllm.logger import init_logger
from vllm.model_executor.layers.layernorm import RMSNorm
from vllm.model_executor.layers.linear import QKVParallelLinear
from vllm.model_executor.layers.logits_processor import LogitsProcessor
from vllm.model_executor.layers.quantization.base_config import (
QuantizationConfig)
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
from vllm.model_executor.models.llama import (LlamaDecoderLayer,
LlamaForCausalLM)
from vllm.v1.sample.metadata import SamplingMetadata
from .utils import AutoWeightsLoader, maybe_prefix
logger = init_logger(__name__)
class LlamaDecoderLayer(LlamaDecoderLayer):
def __init__(
self,
config: LlamaConfig,
quant_config: Optional[QuantizationConfig] = None,
prefix: str = "",
) -> None:
super().__init__(config, quant_config=quant_config, prefix=prefix)
# override qkv
self.self_attn.qkv_proj = QKVParallelLinear(
2 * self.hidden_size,
self.self_attn.head_dim,
self.self_attn.total_num_heads,
self.self_attn.total_num_kv_heads,
bias=False,
quant_config=quant_config,
prefix=maybe_prefix(prefix, "qkv_proj"),
)
self.hidden_norm = RMSNorm(config.hidden_size, eps=config.rms_norm_eps)
def forward(
self,
positions: torch.Tensor,
embeds: torch.Tensor,
hidden_states: torch.Tensor,
residual: Optional[torch.Tensor],
) -> tuple[torch.Tensor, torch.Tensor]:
residual = hidden_states
embeds = self.input_layernorm(embeds)
hidden_states = self.hidden_norm(hidden_states)
hidden_states = torch.cat([embeds, hidden_states], dim=-1)
# Self Attention
hidden_states = self.self_attn(
positions=positions,
hidden_states=hidden_states,
)
hidden_states, residual = self.post_attention_layernorm(
hidden_states, residual)
# Fully Connected
hidden_states = self.mlp(hidden_states)
return hidden_states, residual
@support_torch_compile
class LlamaModel(nn.Module):
def __init__(
self,
*,
vllm_config: VllmConfig,
start_layer_id: int = 0,
prefix: str = "",
) -> None:
super().__init__()
self.config = vllm_config. \
speculative_config.draft_model_config.hf_config
self.vocab_size = self.config.vocab_size
self.embed_tokens = VocabParallelEmbedding(
self.config.vocab_size,
self.config.hidden_size,
prefix=maybe_prefix(prefix, "embed_tokens"),
)
self.layers = nn.ModuleList([
LlamaDecoderLayer(
self.config,
prefix=maybe_prefix(prefix, f"layers.{start_layer_id}"),
)
])
if hasattr(self.config, "target_hidden_size"):
self.fc = torch.nn.Linear(self.config.target_hidden_size * 3,
self.config.hidden_size,
bias=False)
else:
self.fc = torch.nn.Linear(self.config.hidden_size * 3,
self.config.hidden_size,
bias=False)
self.norm = RMSNorm(
self.config.hidden_size,
eps=self.config.rms_norm_eps,
)
def forward(
self,
input_ids: torch.Tensor,
positions: torch.Tensor,
hidden_states: torch.Tensor,
) -> tuple[torch.Tensor, torch.Tensor]:
input_embeds = self.embed_tokens(input_ids)
assert hidden_states.shape[-1] == input_embeds.shape[-1]
residual = None
hidden_states, residual = self.layers[0](
positions,
input_embeds,
hidden_states,
residual,
)
hidden_states, hidden_prenorm = self.norm(hidden_states, residual)
return hidden_states, hidden_prenorm
def load_weights(self, weights: Iterable[tuple[str,
torch.Tensor]]) -> set[str]:
stacked_params_mapping = [
# (param_name, shard_name, shard_id)
(".qkv_proj", ".q_proj", "q"),
(".qkv_proj", ".k_proj", "k"),
(".qkv_proj", ".v_proj", "v"),
(".gate_up_proj", ".gate_proj", 0),
(".gate_up_proj", ".up_proj", 1),
]
params_dict = dict(self.named_parameters())
loaded_params: set[str] = set()
for name, loaded_weight in weights:
if 'midlayer.' in name:
name = name.replace('midlayer.', 'layers.0.')
for param_name, weight_name, shard_id in stacked_params_mapping:
if weight_name not in name:
continue
name = name.replace(weight_name, param_name)
param = params_dict[name]
weight_loader = param.weight_loader
weight_loader(param, loaded_weight, shard_id)
break
else:
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 Eagle3LlamaForCausalLM(LlamaForCausalLM):
def __init__(self, *, vllm_config: VllmConfig, prefix: str = ""):
nn.Module.__init__(self)
self.config = vllm_config. \
speculative_config.draft_model_config.hf_config
target_layer_num = vllm_config.model_config.get_num_layers(
vllm_config.parallel_config)
self.model = LlamaModel(vllm_config=vllm_config,
prefix="model",
start_layer_id=target_layer_num)
logit_scale = getattr(self.config, "logit_scale", 1.0)
self.lm_head = ParallelLMHead(
self.config.draft_vocab_size,
self.config.hidden_size,
org_num_embeddings=self.config.draft_vocab_size,
padding_size=(DEFAULT_VOCAB_PADDING_SIZE),
prefix="")
self.logits_processor = LogitsProcessor(self.config.draft_vocab_size,
scale=logit_scale)
self.draft_id_to_target_id = nn.Parameter(
torch.zeros(self.config.draft_vocab_size, dtype=torch.long),
requires_grad=False,
)
def forward(
self,
input_ids: torch.Tensor,
positions: torch.Tensor,
hidden_states: torch.Tensor,
) -> tuple[torch.Tensor, torch.Tensor]:
return self.model(input_ids, positions, 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)
if self.draft_id_to_target_id is None:
assert logits.shape[1] == self.config.vocab_size, \
"Expected logits to have shape " \
f"(*, {self.config.vocab_size}), but got {logits.shape}"
return logits
base = torch.arange(self.config.draft_vocab_size, device=logits.device)
targets = base + self.draft_id_to_target_id
logits_new = logits.new_full((
logits.shape[0],
self.config.vocab_size,
), float('-inf'))
logits_new[:, targets] = logits
return logits_new
def combine_hidden_states(
self,
hidden_states: torch.Tensor,
) -> torch.Tensor:
# combine multiple auxiliary hidden states returned by eagle3
return self.model.fc(hidden_states)
def load_weights(self, weights: Iterable[tuple[str, torch.Tensor]]):
model_weights = {}
includes_draft_id_mapping = False
includes_embed_tokens = False
for name, loaded_weight in weights:
if "t2d" in name:
continue
if "d2t" in name:
name = name.replace("d2t", "draft_id_to_target_id")
includes_draft_id_mapping = True
elif "lm_head" not in name:
name = "model." + name
if "embed_tokens" in name:
includes_embed_tokens = True
model_weights[name] = loaded_weight
skip_substrs = []
if not includes_draft_id_mapping:
skip_substrs.append("draft_id_to_target_id")
if not includes_embed_tokens:
skip_substrs.append("embed_tokens")
loader = AutoWeightsLoader(
self,
skip_prefixes=None,
skip_substrs=skip_substrs,
)
loader.load_weights(model_weights.items())