[None][fix] Avoid unnecessary concat in attn_output_gate case. (#8094)

Signed-off-by: Yuxian Qiu <142763828+yuxianq@users.noreply.github.com>

Author: yuxianq

tensorrt_llm/_torch/modules/attention.py

@@ -538,10 +538,9 @@ def forward(
                 t.reshape(*orig_shape, -1) for t in torch.chunk(
                     q_gate.view(*orig_shape, self.num_heads, -1), 2, dim=-1)
             ]
-            ### TODO: avoid the redundant split and concat
-            qkv = torch.concat([q, k, v], dim=-1)
+        else:
+            q, k, v = qkv, None, None
 
-        q, k, v = qkv, None, None
         q, k, v = self.apply_rope(q, k, v, position_ids)
         q, k, v = self.convert_qkv(q, k, v)
 

tensorrt_llm/_torch/modules/qk_norm_attention.py

@@ -249,6 +249,7 @@ def apply_rope(self, q: torch.Tensor, k: Optional[torch.Tensor],
             else:
                 return q, k, v
 
-        assert k is None and v is None, "The input should be a concatenated qkv tensor to apply_qk_norm_rope"
         qkv = q
+        if k is not None and v is not None:
+            qkv = torch.concat([q, k, v], dim=-1)
         return self.apply_qk_norm_rope(qkv, position_ids)