vllm/vllm/model_executor/models/deepseek_mtp.py
Benjamin Chislett 9804145cac
[Model][Speculative Decoding] Expand DeepSeek MTP code to support k > n_predict (#13626)
Signed-off-by: Benjamin Chislett <benjamin.chislett@centml.ai>
2025-02-27 15:28:08 -08:00

278 lines
11 KiB
Python

# SPDX-License-Identifier: Apache-2.0
from typing import Iterable, Optional, Set, Tuple
import torch
import torch.nn as nn
from transformers import PretrainedConfig
from vllm.config import CacheConfig, ModelConfig, VllmConfig
from vllm.model_executor.layers.fused_moe import FusedMoE
from vllm.model_executor.layers.layernorm import RMSNorm
from vllm.model_executor.layers.logits_processor import LogitsProcessor
from vllm.model_executor.layers.quantization import QuantizationConfig
from vllm.model_executor.layers.sampler import SamplerOutput, get_sampler
from vllm.model_executor.layers.vocab_parallel_embedding import (
ParallelLMHead, VocabParallelEmbedding)
from vllm.model_executor.model_loader.weight_utils import default_weight_loader
from vllm.model_executor.sampling_metadata import SamplingMetadata
from vllm.sequence import IntermediateTensors
from .deepseek_v2 import (DeepseekV2DecoderLayer,
get_spec_layer_idx_from_weight_name)
from .utils import maybe_prefix
class SharedHead(nn.Module):
def __init__(
self,
config: PretrainedConfig,
quant_config: Optional[QuantizationConfig] = None,
) -> None:
super().__init__()
self.norm = RMSNorm(config.hidden_size, eps=config.rms_norm_eps)
self.head = ParallelLMHead(config.vocab_size,
config.hidden_size,
quant_config=quant_config)
def forward(self, hidden_states: torch.Tensor) -> torch.Tensor:
return self.norm(hidden_states)
class DeepSeekMultiTokenPredictorLayer(nn.Module):
def __init__(
self,
config: PretrainedConfig,
prefix: str,
model_config: ModelConfig,
cache_config: Optional[CacheConfig] = None,
quant_config: Optional[QuantizationConfig] = None,
) -> None:
super().__init__()
self.embed_tokens = VocabParallelEmbedding(
config.vocab_size,
config.hidden_size,
)
self.enorm = RMSNorm(config.hidden_size, eps=config.rms_norm_eps)
self.hnorm = RMSNorm(config.hidden_size, eps=config.rms_norm_eps)
self.eh_proj = nn.Linear(config.hidden_size * 2,
config.hidden_size,
bias=False)
self.shared_head = SharedHead(config=config, quant_config=quant_config)
self.mtp_block = DeepseekV2DecoderLayer(config, prefix, model_config,
cache_config, quant_config)
def forward(
self,
input_ids: torch.Tensor,
positions: torch.Tensor,
previous_hidden_states: torch.Tensor,
inputs_embeds: Optional[torch.Tensor] = None,
spec_step_index: int = 0,
) -> torch.Tensor:
if inputs_embeds is None:
inputs_embeds = self.embed_tokens(input_ids)
assert inputs_embeds is not None
# masking inputs at position 0, as not needed by MTP
inputs_embeds[positions == 0] = 0
inputs_embeds = self.enorm(inputs_embeds)
previous_hidden_states = self.hnorm(previous_hidden_states)
hidden_states = self.eh_proj(
torch.cat([inputs_embeds, previous_hidden_states], dim=-1))
hidden_states, residual = self.mtp_block(positions=positions,
hidden_states=hidden_states,
residual=None)
hidden_states = residual + hidden_states
return hidden_states
class DeepSeekMultiTokenPredictor(nn.Module):
def __init__(self, *, vllm_config: VllmConfig, prefix: str = ""):
super().__init__()
config = vllm_config.model_config.hf_config
self.mtp_start_layer_idx = config.num_hidden_layers
self.num_mtp_layers = config.num_nextn_predict_layers
# to map the exact layer index from weights
self.layers = torch.nn.ModuleDict({
str(idx):
DeepSeekMultiTokenPredictorLayer(
config,
f"{prefix}.layers.{idx}",
model_config=vllm_config.model_config,
cache_config=vllm_config.cache_config,
quant_config=vllm_config.quant_config,
)
for idx in range(self.mtp_start_layer_idx,
self.mtp_start_layer_idx + self.num_mtp_layers)
})
self.logits_processor = LogitsProcessor(config.vocab_size)
def forward(
self,
input_ids: torch.Tensor,
positions: torch.Tensor,
previous_hidden_states: torch.Tensor,
inputs_embeds: Optional[torch.Tensor] = None,
spec_step_idx: int = 0,
) -> torch.Tensor:
current_step_idx = (spec_step_idx % self.num_mtp_layers)
return self.layers[str(self.mtp_start_layer_idx + current_step_idx)](
input_ids,
positions,
previous_hidden_states,
inputs_embeds,
current_step_idx,
)
def compute_logits(
self,
hidden_states: torch.Tensor,
sampling_metadata: SamplingMetadata,
spec_step_idx: int = 0,
) -> torch.Tensor:
current_step_idx = (spec_step_idx % self.num_mtp_layers)
mtp_layer = self.layers[str(self.mtp_start_layer_idx +
current_step_idx)]
logits = self.logits_processor(mtp_layer.shared_head.head,
mtp_layer.shared_head(hidden_states),
sampling_metadata)
return logits
class DeepSeekMTP(nn.Module):
def __init__(self, *, vllm_config: VllmConfig, prefix: str = ""):
super().__init__()
self.config = vllm_config.model_config.hf_config
self.model = DeepSeekMultiTokenPredictor(vllm_config=vllm_config,
prefix=maybe_prefix(
prefix, "model"))
self.sampler = get_sampler()
def forward(
self,
input_ids: torch.Tensor,
positions: torch.Tensor,
previous_hidden_states: torch.Tensor,
intermediate_tensors: Optional[IntermediateTensors] = None,
inputs_embeds: Optional[torch.Tensor] = None,
spec_step_idx: int = 0,
) -> torch.Tensor:
hidden_states = self.model(input_ids, positions,
previous_hidden_states, inputs_embeds,
spec_step_idx)
return hidden_states
def compute_logits(
self,
hidden_states: torch.Tensor,
sampling_metadata: SamplingMetadata,
spec_step_idx: int = 0,
) -> Optional[torch.Tensor]:
return self.model.compute_logits(hidden_states, sampling_metadata,
spec_step_idx)
def sample(
self,
logits: torch.Tensor,
sampling_metadata: SamplingMetadata,
) -> Optional[SamplerOutput]:
next_tokens = self.sampler(logits, sampling_metadata)
return next_tokens
def load_weights(self, weights: Iterable[Tuple[str,
torch.Tensor]]) -> Set[str]:
stacked_params_mapping = [
("gate_up_proj", "gate_proj", 0),
("gate_up_proj", "up_proj", 1),
]
expert_params_mapping = FusedMoE.make_expert_params_mapping(
ckpt_gate_proj_name="gate_proj",
ckpt_down_proj_name="down_proj",
ckpt_up_proj_name="up_proj",
num_experts=self.config.n_routed_experts)
params_dict = dict(self.named_parameters())
loaded_params: Set[str] = set()
for name, loaded_weight in weights:
if "rotary_emb.inv_freq" in name:
continue
spec_layer = get_spec_layer_idx_from_weight_name(self.config, name)
if spec_layer is None:
continue
name = self._rewrite_spec_layer_name(spec_layer, name)
for (param_name, weight_name, shard_id) in stacked_params_mapping:
# Skip non-stacked layers and experts (experts handled below).
if weight_name not in name:
continue
# We have mlp.experts[0].gate_proj in the checkpoint.
# Since we handle the experts below in expert_params_mapping,
# we need to skip here BEFORE we update the name, otherwise
# name will be updated to mlp.experts[0].gate_up_proj, which
# will then be updated below in expert_params_mapping
# for mlp.experts[0].gate_gate_up_proj, which breaks load.
if (("mlp.experts." in name) and name not in params_dict):
continue
name = name.replace(weight_name, param_name)
# Skip loading extra bias for GPTQ models.
if name.endswith(".bias") and name not in params_dict:
continue
param = params_dict[name]
weight_loader = param.weight_loader
weight_loader(param, loaded_weight, shard_id)
break
else:
for mapping in expert_params_mapping:
param_name, weight_name, expert_id, shard_id = 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,
name,
shard_id=shard_id,
expert_id=expert_id)
break
else:
# Skip loading extra bias for GPTQ models.
if name.endswith(".bias") and name not in params_dict:
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
def _rewrite_spec_layer_name(self, spec_layer: int, name: str) -> str:
"""
Rewrite the weight name to match the format of the original model.
Add .mtp_block for modules in transformer layer block for spec layer
"""
spec_layer_weight_names = [
"embed_tokens", "enorm", "hnorm", "eh_proj", "shared_head"
]
spec_layer_weight = False
for weight_name in spec_layer_weight_names:
if weight_name in name:
spec_layer_weight = True
break
if not spec_layer_weight:
# treat rest weights as weights for transformer layer block
name = name.replace(f"model.layers.{spec_layer}.",
f"model.layers.{spec_layer}.mtp_block.")
return name