refactor: standardize packed 3d inference

- keep training attention on dense 4d tensors
- use packed 3d tensors with KV cache for inference
- extend CUDA rotary embedding to packed 3d inputs
- adapt torch, CUDA and FlashAttention backend dispatch
This commit is contained in:
2026-08-16 13:24:02 +08:00
parent 0dd9a417b7
commit 3406157431
15 changed files with 301 additions and 248 deletions
+11 -9
View File
@@ -56,9 +56,7 @@ class GQA(nn.Module):
self.gate = Linear(dim, dim)
def _split_heads(self, x: Tensor, n_heads) -> Tensor:
batch_size, seq_len, _ = x.shape
x = x.reshape(batch_size, seq_len, n_heads, self.head_dim)
return x
return x.reshape(*x.shape[:-1], n_heads, self.head_dim)
def forward(
self,
@@ -67,6 +65,7 @@ class GQA(nn.Module):
attn_mask: Tensor = None,
kv_cache: Optional[KVCache] = None,
is_causal: bool = False,
fwd: Optional[str] = None,
) -> Tensor:
q = self._split_heads(self.q_proj(x), self.n_heads)
k = self._split_heads(self.k_proj(x), self.n_kv_heads)
@@ -76,7 +75,9 @@ class GQA(nn.Module):
if self.use_qk_norm:
q, k = self.q_norm(q), self.k_norm(k)
sdqa_out = attention(q, k, v, kv_cache, self.layer_id, attn_mask, is_causal)
sdqa_out = attention(
q, k, v, kv_cache, self.layer_id, attn_mask, is_causal, fwd
).reshape(*x.shape[:-1], self.dim)
if self.use_gated_attention:
sdqa_out = sdqa_out * F.sigmoid(self.gate(x))
@@ -141,17 +142,16 @@ class MLA(nn.Module):
attn_mask: Tensor = None,
kv_cache: Optional[KVCache] = None,
is_causal: bool = False,
fwd: Optional[str] = None,
) -> Tensor:
bsz, seq_len, _ = x.size()
q = self.q_proj(x)
q = q.view(bsz, seq_len, self.n_heads, self.head_dim)
q = q.reshape(*x.shape[:-1], self.n_heads, self.head_dim)
kv_compressed = self.kv_a_proj(x)
kv_compressed = self.kv_norm(kv_compressed)
kv = self.kv_b_proj(kv_compressed)
kv = kv.view(bsz, seq_len, self.n_kv_heads, -1)
kv = kv.reshape(*x.shape[:-1], self.n_kv_heads, -1)
k_nope, k_rope, v = torch.split(
kv, [self.qk_nope_head_dim, self.qk_rope_head_dim, self.head_dim], dim=-1
@@ -171,7 +171,9 @@ class MLA(nn.Module):
q = self.q_norm(q)
k = self.k_norm(k)
attn_out = attention(q, k, v, kv_cache, self.layer_id, attn_mask, is_causal)
attn_out = attention(
q, k, v, kv_cache, self.layer_id, attn_mask, is_causal, fwd
).reshape(*x.shape[:-1], self.dim)
if self.use_gated_attention:
attn_out = attn_out * F.sigmoid(self.gate(x))