61 transformer blocks › 58 MoE blocks › Sparse latent attention
Normalized query latent
×tensorqr
Read by the query heads and the lightning indexer.
- shape
- [B batch, T positions, 1536 q latent]
Sources
Contextual evidence from Query compression
MLA owns a query down-projection, query RMSNorm and up-projection, a joint key–value down-projection that also emits the shared rotary key, a latent RMSNorm, a key–value up-projection and an output projection.
mla-init · deepseek-ai/DeepSeek-V3.2-Exp / inference/model.py
Pinned revision 87e509a2e5a1 ↗ · lines 523–539
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self.qk_head_dim = args.qk_nope_head_dim + args.qk_rope_head_dim
self.v_head_dim = args.v_head_dim
self.wq_a = Linear(self.dim, self.q_lora_rank)
self.q_norm = RMSNorm(self.q_lora_rank)
self.wq_b = ColumnParallelLinear(self.q_lora_rank, self.n_heads * self.qk_head_dim)
self.wkv_a = Linear(self.dim, self.kv_lora_rank + self.qk_rope_head_dim)
self.kv_norm = RMSNorm(self.kv_lora_rank)
self.wkv_b = ColumnParallelLinear(self.kv_lora_rank, self.n_heads * (self.qk_nope_head_dim + self.v_head_dim))
self.wo = RowParallelLinear(self.n_heads * self.v_head_dim, self.dim)
self.softmax_scale = self.qk_head_dim ** -0.5
self.scale_fmt = args.scale_fmt
if args.max_seq_len > args.original_seq_len:
mscale = 0.1 * args.mscale * math.log(args.rope_factor) + 1.0
self.softmax_scale = self.softmax_scale * mscale * mscale
self.indexer = Indexer(args)Contextual evidence from Query compression
Queries are produced through a low-rank latent, split into a non-rotated and a rotated part, and rotated.
mla-queries · deepseek-ai/DeepSeek-V3.2-Exp / inference/model.py
Pinned revision 87e509a2e5a1 ↗ · lines 560–564
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qr = self.q_norm(self.wq_a(x))
q = self.wq_b(qr)
q = q.view(bsz, seqlen, self.n_local_heads, self.qk_head_dim)
q_nope, q_pe = torch.split(q, [self.qk_nope_head_dim, self.qk_rope_head_dim], dim=-1)
q_pe = apply_rotary_emb(q_pe, freqs_cis)Contextual evidence from Lightning indexer
The lightning indexer owns a query up-projection from the query latent, a single key projection with LayerNorm, and a per-head weight projection.
indexer-init · deepseek-ai/DeepSeek-V3.2-Exp / inference/model.py
Pinned revision 87e509a2e5a1 ↗ · lines 436–452
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def __init__(self, args: ModelArgs):
super().__init__()
self.dim: int = args.dim
self.n_heads: int = args.index_n_heads
self.n_local_heads = args.index_n_heads // world_size
self.head_dim: int = args.index_head_dim
self.rope_head_dim: int = args.qk_rope_head_dim
self.index_topk: int = args.index_topk
self.q_lora_rank: int = args.q_lora_rank
self.wq_b = Linear(self.q_lora_rank, self.n_heads * self.head_dim)
self.wk = Linear(self.dim, self.head_dim)
self.k_norm = LayerNorm(self.head_dim)
# weights_proj in the checkpoint is stored in bf16, while the parameters here are stored in fp32 for convenient.
self.weights_proj = Linear(self.dim, self.n_heads, dtype=torch.float32)
self.softmax_scale = self.head_dim ** -0.5
self.scale_fmt = args.scale_fmt
Contextual evidence from Lightning indexer
Indexer scores combine per-head query–key products with learned per-head weights, add the causal mask and keep the top-k positions for each query.
indexer-forward · deepseek-ai/DeepSeek-V3.2-Exp / inference/model.py
Pinned revision 87e509a2e5a1 ↗ · lines 457–487
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def forward(self, x: torch.Tensor, qr: torch.Tensor, start_pos: int, freqs_cis: torch.Tensor, mask: Optional[torch.Tensor]):
bsz, seqlen, _ = x.size()
end_pos = start_pos + seqlen
q = self.wq_b(qr)
q = q.view(bsz, seqlen, self.n_heads, self.head_dim)
q_pe, q_nope = torch.split(q, [self.rope_head_dim, self.head_dim - self.rope_head_dim], dim=-1)
# rope in indexer is not interleaved
q_pe = apply_rotary_emb(q_pe, freqs_cis, False)
q = torch.cat([q_pe, q_nope], dim=-1)
k = self.wk(x)
k = self.k_norm(k)
k_pe, k_nope = torch.split(k, [self.rope_head_dim, self.head_dim - self.rope_head_dim], dim=-1)
# rope in indexer is not interleaved
k_pe = apply_rotary_emb(k_pe.unsqueeze(2), freqs_cis, False).squeeze(2)
k = torch.cat([k_pe, k_nope], dim=-1)
q = rotate_activation(q)
k = rotate_activation(k)
q_fp8, q_scale = act_quant(q, block_size, self.scale_fmt)
k_fp8, k_scale = act_quant(k, block_size, self.scale_fmt)
self.k_cache[:bsz, start_pos:end_pos] = k_fp8
self.k_scale_cache[:bsz, start_pos:end_pos] = k_scale
weights = self.weights_proj(x.float()) * self.n_heads ** -0.5
weights = weights.unsqueeze(-1) * q_scale * self.softmax_scale
index_score = fp8_index(q_fp8.contiguous(), weights, self.k_cache[:bsz, :end_pos].contiguous(), self.k_scale_cache[:bsz, :end_pos].contiguous())
if mask is not None:
index_score += mask
topk_indices = index_score.topk(min(self.index_topk, end_pos), dim=-1)[1]
topk_indices_ = topk_indices.clone()
dist.broadcast(topk_indices_, src=0)
assert torch.all(topk_indices == topk_indices_), f"{topk_indices=} {topk_indices_=}"
return topk_indicesContextual evidence from Lightning indexer
The index kernel applies ReLU to each head’s query–key product, weights it per head and sums over heads.
index-kernel · deepseek-ai/DeepSeek-V3.2-Exp / inference/kernel.py
Pinned revision 87e509a2e5a1 ↗ · lines 260–273
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"""
Perform index score using FP8 precision.
Args:
q (torch.Tensor): The Q tensor, must be contiguous.
q_s (torch.Tensor): The scaling factor for Q (float), must be contiguous.
k (torch.Tensor): The K tensor, must be contiguous.
k_s (torch.Tensor): The scaling factor for K (e8m0 here), must be contiguous.
fp8 q @ fp8 k -> fp32 logits
relu(fp32 logits) * q_s (weights) -> fp32 logits
fp32 logits -> fp32 logits_sum
fp32 logits_sum * k_s (e8m0) -> fp32 index_score
"""