vllm/vllm/model_executor/models/deepseek_mtp.py
Benjamin Chislett f381cf2302
[Bugfix] Fix broken MTP weight loading for FP8 KV Scales (#27227)
Signed-off-by: Benjamin Chislett <bchislett@nvidia.com>
2025-10-20 22:51:44 -07:00

335 lines
12 KiB
Python

# SPDX-License-Identifier: Apache-2.0
# SPDX-FileCopyrightText: Copyright contributors to the vLLM project
from collections.abc import Iterable
import torch
import torch.nn as nn
from transformers import PretrainedConfig
from vllm.compilation.decorators import support_torch_compile
from vllm.config import 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.vocab_parallel_embedding import (
ParallelLMHead,
VocabParallelEmbedding,
)
from vllm.model_executor.model_loader.weight_utils import (
default_weight_loader,
maybe_remap_kv_scale_name,
)
from vllm.platforms import current_platform
from vllm.sequence import IntermediateTensors
from .deepseek_v2 import (
DeepseekV2DecoderLayer,
get_spec_layer_idx_from_weight_name,
)
from .interfaces import SupportsPP
from .utils import maybe_prefix
class SharedHead(nn.Module):
def __init__(
self,
config: PretrainedConfig,
prefix: str,
quant_config: QuantizationConfig | None = 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,
prefix=maybe_prefix(prefix, "head"),
)
def forward(self, hidden_states: torch.Tensor) -> torch.Tensor:
return self.norm(hidden_states)
class DeepSeekMultiTokenPredictorLayer(nn.Module):
def __init__(self, vllm_config: VllmConfig, prefix: str) -> None:
super().__init__()
config = vllm_config.speculative_config.draft_model_config.hf_config
self.config = config
quant_config = vllm_config.quant_config
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.device = current_platform.device_type
self.is_v32 = hasattr(config, "index_topk")
if self.is_v32:
topk_tokens = config.index_topk
topk_indices_buffer = torch.empty(
vllm_config.scheduler_config.max_num_batched_tokens,
topk_tokens,
dtype=torch.int32,
device=self.device,
)
else:
topk_indices_buffer = None
self.shared_head = SharedHead(
config=config, prefix=prefix, quant_config=quant_config
)
self.mtp_block = DeepseekV2DecoderLayer(
vllm_config,
prefix,
config=self.config,
topk_indices_buffer=topk_indices_buffer,
)
def forward(
self,
input_ids: torch.Tensor,
positions: torch.Tensor,
previous_hidden_states: torch.Tensor,
inputs_embeds: torch.Tensor | None = None,
spec_step_index: int = 0,
) -> torch.Tensor:
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(
vllm_config, f"{prefix}.layers.{idx}"
)
for idx in range(
self.mtp_start_layer_idx,
self.mtp_start_layer_idx + self.num_mtp_layers,
)
}
)
self.embed_tokens = VocabParallelEmbedding(
config.vocab_size,
config.hidden_size,
)
self.logits_processor = LogitsProcessor(config.vocab_size)
def get_input_embeddings(self, input_ids: torch.Tensor) -> torch.Tensor:
return self.embed_tokens(input_ids)
def forward(
self,
input_ids: torch.Tensor,
positions: torch.Tensor,
previous_hidden_states: torch.Tensor,
inputs_embeds: torch.Tensor | None = None,
spec_step_idx: int = 0,
) -> torch.Tensor:
if inputs_embeds is None:
inputs_embeds = self.embed_tokens(input_ids)
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,
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)
)
return logits
@support_torch_compile
class DeepSeekMTP(nn.Module, SupportsPP):
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")
)
def get_input_embeddings(self, input_ids: torch.Tensor) -> torch.Tensor:
return self.model.get_input_embeddings(input_ids)
def forward(
self,
input_ids: torch.Tensor,
positions: torch.Tensor,
hidden_states: torch.Tensor,
intermediate_tensors: IntermediateTensors | None = None,
inputs_embeds: torch.Tensor | None = None,
spec_step_idx: int = 0,
) -> torch.Tensor:
hidden_states = self.model(
input_ids, positions, hidden_states, inputs_embeds, spec_step_idx
)
return hidden_states
def compute_logits(
self,
hidden_states: torch.Tensor,
spec_step_idx: int = 0,
) -> torch.Tensor | None:
return self.model.compute_logits(hidden_states, spec_step_idx)
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),
("fused_qkv_a_proj", "q_a_proj", 0),
("fused_qkv_a_proj", "kv_a_proj_with_mqa", 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_mapped = name.replace(weight_name, param_name)
# QKV fusion is optional, fall back to normal
# weight loading if it's not enabled
if (
param_name == "fused_qkv_a_proj"
) and name_mapped not in params_dict:
continue
else:
name = name_mapped
# 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
name = maybe_remap_kv_scale_name(name, params_dict)
if name is None:
continue
# According to DeepSeek-V3 Technical Report, MTP modules
# shares embedding layer. We only load the first weights.
if (
spec_layer != self.model.mtp_start_layer_idx
and ".layers" not in name
):
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
and rename shared layer weights to be top level.
"""
spec_layer_weight_names = [
"embed_tokens",
"enorm",
"hnorm",
"eh_proj",
"shared_head",
]
shared_weight_names = ["embed_tokens"]
spec_layer_weight = False
shared_weight = False
for weight_name in spec_layer_weight_names:
if weight_name in name:
spec_layer_weight = True
if weight_name in shared_weight_names:
shared_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."
)
elif shared_weight:
# treat shared weights as top level weights
name = name.replace(f"model.layers.{spec_layer}.", "model.")
return name