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sglang/python/sglang/srt/models/qwen3_5_mtp.py
2026-03-09 16:05:32 +08:00

361 lines
13 KiB
Python

# Copyright 2023-2024 SGLang Team
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
# ==============================================================================
"""Inference-only Qwen3_5 MTP model."""
import logging
from typing import Iterable, Optional, Tuple
import torch
from torch import nn
from transformers import PretrainedConfig
from sglang.srt.distributed import get_pp_group, get_tensor_model_parallel_world_size
from sglang.srt.eplb.expert_distribution import get_global_expert_distribution_recorder
from sglang.srt.eplb.expert_location import ModelConfigForExpertLocation
from sglang.srt.layers.layernorm import GemmaRMSNorm
from sglang.srt.layers.logits_processor import LogitsProcessor
from sglang.srt.layers.moe.fused_moe_triton.layer import FusedMoE
from sglang.srt.layers.vocab_parallel_embedding import ParallelLMHead
from sglang.srt.model_executor.forward_batch_info import ForwardBatch
from sglang.srt.model_loader.weight_utils import default_weight_loader
from sglang.srt.models.qwen3_5 import Qwen3_5ForCausalLM
from sglang.srt.utils import add_prefix
logger = logging.getLogger(__name__)
class Qwen3_5ForCausalLMMTP(nn.Module):
def __init__(
self,
config: PretrainedConfig,
quant_config=None,
prefix: str = "",
) -> None:
nn.Module.__init__(self)
self.is_multimodal = hasattr(config, "text_config")
if self.is_multimodal:
config = config.text_config
# The MTP model is unquantized in the nvfp4 checkpoint.
if quant_config and quant_config.get_name() == "modelopt_fp4":
quant_config = None
self.config = config
self.tp_size = get_tensor_model_parallel_world_size()
self.quant_config = quant_config
self.pp_group = get_pp_group()
self.fc = nn.Linear(2 * config.hidden_size, config.hidden_size, bias=False)
RMSNorm_cls = GemmaRMSNorm
self.pre_fc_norm_embedding = RMSNorm_cls(
config.hidden_size, config.rms_norm_eps
)
self.pre_fc_norm_hidden = RMSNorm_cls(config.hidden_size, config.rms_norm_eps)
config.num_hidden_layers = 1
config.full_attention_interval = 1
self.model = Qwen3_5ForCausalLM(
config,
quant_config,
prefix=add_prefix("mtp", prefix),
is_nextn=True,
)
if get_pp_group().is_last_rank:
if config.tie_word_embeddings:
self.lm_head = self.model.embed_tokens
else:
self.lm_head = ParallelLMHead(
config.vocab_size,
config.hidden_size,
quant_config=quant_config,
prefix=add_prefix("lm_head", prefix),
)
self.logits_processor = LogitsProcessor(config)
@classmethod
def get_model_config_for_expert_location(cls, config):
text_config = getattr(config, "text_config", config)
return ModelConfigForExpertLocation(
num_layers=text_config.num_hidden_layers,
num_logical_experts=text_config.num_experts,
num_groups=None,
)
def get_embed_and_head(self):
return self.model.embed_tokens.weight, self.lm_head.weight
def set_embed_and_head(self, embed, head):
del self.model.embed_tokens.weight
if not self.config.tie_word_embeddings:
del self.lm_head.weight
self.model.embed_tokens.weight = embed
self.lm_head.weight = head
torch.cuda.empty_cache()
torch.cuda.synchronize()
@torch.no_grad()
def forward(
self,
input_ids: torch.Tensor,
positions: torch.Tensor,
forward_batch: ForwardBatch,
input_embeds: Optional[torch.Tensor] = None,
**kwargs,
):
assert input_embeds is None
input_embeds = forward_batch.mm_input_embeds
if (
forward_batch.forward_mode.is_extend()
and forward_batch.contains_mm_inputs()
and not forward_batch.forward_mode.is_draft_extend(include_v2=True)
):
assert input_embeds is not None
input_embeds = torch.cat(
[input_embeds[:-1], self.model.embed_tokens(input_ids[-1].unsqueeze(0))]
)
if input_embeds is None:
input_embeds = self.model.embed_tokens(input_ids)
hidden_states = forward_batch.spec_info.hidden_states
if not forward_batch.forward_mode.is_idle():
input_embeds = self.pre_fc_norm_embedding(input_embeds)
hidden_states = self.pre_fc_norm_hidden(hidden_states)
hidden_states = torch.cat([input_embeds, hidden_states], dim=-1)
hidden_states = self.fc(hidden_states)
with get_global_expert_distribution_recorder().disable_this_region():
hidden_states = self.model(
input_ids,
positions,
forward_batch,
hidden_states,
)
return self.logits_processor(
input_ids, hidden_states, self.lm_head, forward_batch
)
def load_weights(
self, weights: Iterable[Tuple[str, torch.Tensor]], is_mtp: bool = False
):
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 for MoE experts (non-fused/fused)
num_experts = getattr(self.config, "num_experts", None)
if num_experts is not None:
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=num_experts,
)
else:
expert_params_mapping = []
# Skip loading extra parameters for GPTQ/modelopt models.
ignore_suffixes = (
".bias",
"_bias",
".k_scale",
"_k_scale",
".v_scale",
"_v_scale",
".weight_scale",
"_weight_scale",
".input_scale",
"_input_scale",
)
# fused experts: experts.w13_weight / experts.w2_weight
is_fused_expert = False
fused_expert_params_mapping = [
("experts.w13_weight", "experts.gate_up_proj", 0, "w1"),
("experts.w2_weight", "experts.down_proj", 0, "w2"),
]
def load_fused_expert_weights(
name: str,
params_dict: dict,
loaded_weight: torch.Tensor,
shard_id: str,
num_experts: int,
):
param = params_dict[name]
weight_loader = param.weight_loader
# Let EP MoE layer handle expert_ids that do not belong to local moe rank
for expert_id in range(num_experts):
curr_expert_weight = loaded_weight[expert_id]
weight_loader(
param,
curr_expert_weight,
name,
shard_id,
expert_id,
)
return True
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
# Only process MTP branch weights
if "mtp" not in name:
continue
if name.startswith("mtp."):
# Remove the mtp. prefix for processing
name = name.replace("mtp.", "model.")
name = name.replace("model.fc", "fc")
name = name.replace("model.pre_fc", "pre_fc")
if ".self_attn." in name:
name = name.replace(".self_attn", "")
# 1) Process stacked parameters (q_proj/k_proj/v_proj & gate_proj/up_proj)
for param_name, weight_name, shard_id in stacked_params_mapping:
# Check if this is a fused expert weight
if "experts.gate_up_proj" in name or "experts.down_proj" in name:
is_fused_expert = True
expert_params_mapping = fused_expert_params_mapping
# Skip non-matching weights
if weight_name not in name:
continue
# Skip MoE experts.* here, handled separately below
if "mlp.experts" in name:
continue
name_mapped = name.replace(weight_name, param_name)
# Skip loading extra parameters for GPTQ/modelopt models.
if (
name_mapped.endswith(ignore_suffixes)
and name_mapped not in params_dict
):
continue
if name_mapped not in params_dict:
continue
param = params_dict[name_mapped]
weight_loader = getattr(param, "weight_loader", default_weight_loader)
weight_loader(param, loaded_weight, shard_id)
name = name_mapped
break
else:
# 2) Process MoE expert weights (including fused experts)
is_expert_weight = False
for mapping in expert_params_mapping:
param_name, weight_name, expert_id, shard_id = mapping
if weight_name not in name:
continue
is_expert_weight = True
name_mapped = name.replace(weight_name, param_name)
# Fused experts: single checkpoint weight contains multiple experts
if is_fused_expert and num_experts is not None:
if "experts.gate_up_proj" in name:
# gate_up_proj fused: split into w1 / w3
loaded_w1, loaded_w3 = loaded_weight.chunk(2, dim=-2)
load_fused_expert_weights(
name_mapped,
params_dict,
loaded_w1,
"w1",
num_experts,
)
load_fused_expert_weights(
name_mapped,
params_dict,
loaded_w3,
"w3",
num_experts,
)
else:
# down_proj fused: distribute entire weight
load_fused_expert_weights(
name_mapped,
params_dict,
loaded_weight,
shard_id,
num_experts,
)
else:
# Non-fused expert, load by expert_id/shard
if (
name_mapped.endswith(ignore_suffixes)
and name_mapped not in params_dict
):
continue
if name_mapped not in params_dict:
break
param = params_dict[name_mapped]
weight_loader = param.weight_loader
weight_loader(
param,
loaded_weight,
name_mapped,
shard_id=shard_id,
expert_id=expert_id,
)
name = name_mapped
break
else:
# Skip expert weight if not handled by current rank
if is_expert_weight:
continue
# 3) Regular non-stacked / non-expert parameters, use default loader
if name.endswith(ignore_suffixes) and name not in params_dict:
continue
if name in params_dict:
param = params_dict[name]
weight_loader = getattr(
param, "weight_loader", default_weight_loader
)
weight_loader(param, loaded_weight)
else:
logger.warning_once(
f"Parameter {name} not found in params_dict, skip loading"
)
loaded_params.add(name)
return loaded_params
EntryClass = [Qwen3_5ForCausalLMMTP]