Support NextN (MTP) speculative decoding for DeepSeek-V3/R1 (#3582)

python/sglang/srt/models/deepseek_v2.py

@@ -519,6 +519,8 @@ class DeepseekV2AttentionMLA(nn.Module):
             # Triton: Use normal computation for prefill and use weight absorption for extend/decode
             if (
                 forward_batch.forward_mode.is_extend()
+                and not forward_batch.forward_mode.is_target_verify()
+                and not forward_batch.forward_mode.is_draft_extend()
                 and forward_batch.extend_prefix_lens.sum() == 0
             ):
                 return self.forward_normal(positions, hidden_states, forward_batch)
@@ -680,6 +682,7 @@ class DeepseekV2DecoderLayer(nn.Module):
         config: PretrainedConfig,
         layer_id: int,
         quant_config: Optional[QuantizationConfig] = None,
+        is_nextn: bool = False,
     ) -> None:
         super().__init__()
         self.hidden_size = config.hidden_size
@@ -731,7 +734,7 @@ class DeepseekV2DecoderLayer(nn.Module):
                 quant_config=quant_config,
                 layer_id=layer_id,
             )
-        if (
+        if is_nextn or (
             config.n_routed_experts is not None
             and layer_id >= config.first_k_dense_replace
             and layer_id % config.moe_layer_freq == 0