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sglang/python/sglang/srt/models/deepseek_v4_nextn.py
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2026-05-30 02:04:51 -07:00

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9.9 KiB
Python

import logging
from typing import Iterable, Optional, Tuple
import torch
import torch.nn.functional as F
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.layers.attention.dsa.utils import (
can_dsa_cp_split,
dsa_use_prefill_cp,
is_dsa_enable_prefill_cp,
is_dsa_prefill_cp_round_robin_split,
)
from sglang.srt.layers.dp_attention import (
_DpGatheredBufferWrapper,
dp_gather_partial,
get_attention_cp_rank,
get_attention_cp_size,
get_attention_dp_size,
is_dp_attention_enabled,
)
from sglang.srt.layers.layernorm import RMSNorm
from sglang.srt.layers.linear import ReplicatedLinear
from sglang.srt.layers.logits_processor import LogitsProcessor
from sglang.srt.layers.moe.utils import get_moe_a2a_backend
from sglang.srt.layers.quantization.base_config import QuantizationConfig
from sglang.srt.layers.utils.cp_utils import (
cp_all_gather_rerange_output,
cp_split_and_rebuild_data,
cp_split_and_rebuild_position,
prepare_context_parallel_metadata,
)
from sglang.srt.layers.vocab_parallel_embedding import (
ParallelLMHead,
VocabParallelEmbedding,
)
from sglang.srt.model_executor.forward_batch_info import ForwardBatch
from sglang.srt.model_executor.forward_context import get_attn_backend
from sglang.srt.models.deepseek_v4 import DeepseekV4DecoderLayer, DeepseekV4ForCausalLM
from sglang.srt.server_args import get_global_server_args
from sglang.srt.utils import add_prefix
logger = logging.getLogger(__name__)
COMPRESS_RATIO_NEXTN_LAYER = 0
class DeepseekV4ModelNextN(nn.Module):
def __init__(
self,
config: PretrainedConfig,
quant_config: Optional[QuantizationConfig] = None,
prefix: str = "",
) -> None:
super().__init__()
self.config = config
self.vocab_size = config.vocab_size
self.embed_tokens = VocabParallelEmbedding(
config.vocab_size,
config.hidden_size,
enable_tp=not is_dp_attention_enabled(),
prefix=add_prefix("embed_tokens", prefix),
)
self.enorm = RMSNorm(config.hidden_size, eps=config.rms_norm_eps)
self.hnorm = RMSNorm(config.hidden_size, eps=config.rms_norm_eps)
self.rms_norm_eps = config.rms_norm_eps
self.hc_eps = config.hc_eps
self.hc_mult = hc_mult = config.hc_mult
hc_dim = hc_mult * config.hidden_size
self.hc_head_fn = nn.Parameter(
torch.empty(hc_mult, hc_dim, dtype=torch.float32)
)
self.hc_head_base = nn.Parameter(torch.empty(hc_mult, dtype=torch.float32))
self.hc_head_scale = nn.Parameter(torch.empty(1, dtype=torch.float32))
self.e_proj = ReplicatedLinear(
config.hidden_size,
config.hidden_size,
bias=False,
quant_config=quant_config,
prefix=add_prefix("e_proj", prefix),
)
self.h_proj = ReplicatedLinear(
config.hidden_size,
config.hidden_size,
bias=False,
quant_config=quant_config,
prefix=add_prefix("h_proj", prefix),
)
layer_name = "decoder"
self.decoder = DeepseekV4DecoderLayer(
config,
layer_id=0,
quant_config=quant_config,
is_nextn=True,
prefix=add_prefix(layer_name, prefix),
alt_streams=None,
compress_ratio_override=COMPRESS_RATIO_NEXTN_LAYER,
)
self.dsa_enable_prefill_cp = is_dsa_enable_prefill_cp()
if self.dsa_enable_prefill_cp:
self.cp_size = get_attention_cp_size()
else:
self.cp_size = None
self.shared_head = nn.Module()
self.shared_head.norm = RMSNorm(config.hidden_size, eps=config.rms_norm_eps)
def hc_head(
self,
x: torch.Tensor,
hc_fn: torch.Tensor,
hc_scale: torch.Tensor,
hc_base: torch.Tensor,
):
shape, dtype = x.size(), x.dtype
x = x.flatten(1).float()
rsqrt = torch.rsqrt(x.square().mean(-1, keepdim=True) + self.rms_norm_eps)
mixes = F.linear(x, hc_fn) * rsqrt
pre = torch.sigmoid(mixes * hc_scale + hc_base) + self.hc_eps
y = torch.sum(pre.unsqueeze(-1) * x.view(shape), dim=1)
return y.to(dtype)
def forward(
self,
input_ids: torch.Tensor,
positions: torch.Tensor,
forward_batch: ForwardBatch,
input_embeds: torch.Tensor = None,
) -> torch.Tensor:
if input_embeds is None:
hidden_states = self.embed_tokens(input_ids)
else:
hidden_states = input_embeds
if hidden_states.shape[0] > 0:
n_tokens = hidden_states.shape[0]
d = self.config.hidden_size
hc_flat = forward_batch.spec_info.hidden_states.view(
n_tokens * self.hc_mult, d
)
h_proj_out, _ = self.h_proj(self.hnorm(hc_flat))
h_proj_hidden_states = h_proj_out.view(n_tokens, self.hc_mult, d)
e_proj_hidden_states, _ = self.e_proj(self.enorm(hidden_states))
hidden_states = e_proj_hidden_states[:, None, :] + h_proj_hidden_states
else:
hidden_states = hidden_states.unsqueeze(1).repeat(1, self.hc_mult, 1)
if get_attention_dp_size() > 1 and get_moe_a2a_backend().is_none():
input_ids_global = torch.empty(
(_DpGatheredBufferWrapper._global_dp_buffer_len, 1),
dtype=input_ids.dtype,
device=input_ids.device,
)
dp_gather_partial(input_ids_global, input_ids[:, None], forward_batch)
input_ids_global = input_ids_global.squeeze(-1)
else:
input_ids_global = input_ids
if dsa_use_prefill_cp(forward_batch):
hidden_states = cp_split_and_rebuild_data(forward_batch, hidden_states)
positions = cp_split_and_rebuild_position(forward_batch, positions)
hidden_states, residual, post, comb = self.decoder(
positions=positions,
hidden_states=hidden_states,
forward_batch=forward_batch,
input_ids=input_ids,
input_ids_global=input_ids_global,
)
if residual is not None:
# NextN has a single decoder layer, so no later layer can consume a
# deferred fused hc_post state.
hidden_states = self.decoder.hc_post(hidden_states, residual, post, comb)
if dsa_use_prefill_cp(forward_batch):
hidden_states = cp_all_gather_rerange_output(
hidden_states,
self.cp_size,
forward_batch,
torch.cuda.current_stream(),
)
pre_hc_head = hidden_states.flatten(1)
hidden_states = self.hc_head(
hidden_states, self.hc_head_fn, self.hc_head_scale, self.hc_head_base
)
hidden_states = self.shared_head.norm(hidden_states)
return hidden_states, pre_hc_head
class DeepseekV4ForCausalLMNextN(DeepseekV4ForCausalLM):
def __init__(
self,
config: PretrainedConfig,
quant_config: Optional[QuantizationConfig] = None,
prefix: str = "",
) -> None:
nn.Module.__init__(self)
self.config = config
self.tp_size = get_tensor_model_parallel_world_size()
self.pp_group = get_pp_group()
self.quant_config = quant_config
self.determine_num_fused_shared_experts()
self.dsa_enable_prefill_cp = is_dsa_enable_prefill_cp()
if self.dsa_enable_prefill_cp:
self.cp_rank = get_attention_cp_rank()
self.cp_size = get_attention_cp_size()
else:
self.cp_rank = None
self.cp_size = None
self.model = DeepseekV4ModelNextN(
config, quant_config, prefix=add_prefix("model", prefix)
)
self.lm_head = ParallelLMHead(
config.vocab_size,
config.hidden_size,
quant_config=quant_config,
prefix=add_prefix("model.shared_head.head", prefix),
use_attn_tp_group=get_global_server_args().enable_dp_lm_head,
)
self.logits_processor = LogitsProcessor(config)
@torch.no_grad()
def forward(
self,
input_ids: torch.Tensor,
positions: torch.Tensor,
forward_batch: ForwardBatch,
) -> torch.Tensor:
if self.dsa_enable_prefill_cp:
if can_dsa_cp_split(len(input_ids), self.cp_size, True, forward_batch):
forward_batch.attn_cp_metadata = prepare_context_parallel_metadata(
len(input_ids),
self.cp_rank,
self.cp_size,
forward_batch.seq_lens_cpu.tolist(),
extend_seqs_len=forward_batch.extend_seq_lens_cpu,
)
if is_dsa_prefill_cp_round_robin_split():
attn_backend = get_attn_backend()
metadata = attn_backend.forward_metadata
core_meta = metadata.core_attn_metadata
core_meta.apply_cp_reindex()
core_meta.init_flashmla_related()
if metadata.indexer_metadata is not None:
metadata.indexer_metadata = (
attn_backend.init_forward_metadata_indexer(core_meta)
)
hidden_states, pre_hc_head = self.model(input_ids, positions, forward_batch)
return self.logits_processor(
input_ids,
hidden_states,
self.lm_head,
forward_batch,
hidden_states_before_norm=pre_hc_head,
)
def load_weights(self, weights: Iterable[Tuple[str, torch.Tensor]]):
super().load_weights(weights, is_nextn=True)
def post_load_weights(self, is_nextn=False, weight_names=None):
super().post_load_weights(is_nextn=True, weight_names=weight_names)
EntryClass = [DeepseekV4ForCausalLMNextN]