[Fix] Support qwen3-next MTP+DP (#10392)

python/sglang/srt/configs/model_config.py

@@ -170,6 +170,7 @@ class ModelConfig:
 
         if is_draft_model and self.hf_config.architectures[0] == "Qwen3NextForCausalLM":
             self.hf_config.architectures[0] = "Qwen3NextForCausalLMMTP"
+            self.hf_config.num_nextn_predict_layers = 1
 
         # Check model type
         self.is_generation = is_generation_model(

python/sglang/srt/layers/logits_processor.py

@@ -185,10 +185,9 @@ class LogitsMetadata:
             )
         else:
             dp_local_start_pos = cumtokens[dp_rank - 1]
-        dp_local_num_tokens = self.global_num_tokens_for_logprob_gpu[dp_rank]
 
         self.dp_local_start_pos = dp_local_start_pos
-        self.dp_local_num_tokens = dp_local_num_tokens
+        self.dp_local_num_tokens = self.global_num_tokens_for_logprob_gpu[dp_rank]
 
         hidden_size = get_dp_hidden_size()
         dtype = get_dp_dtype()

python/sglang/srt/mem_cache/memory_pool.py

@@ -52,6 +52,10 @@ if _is_npu:
     import torch_npu
 
 
+def get_tensor_size_bytes(t: torch.Tensor):
+    return np.prod(t.shape) * t.dtype.itemsize
+
+
 class ReqToTokenPool:
     """A memory pool that maps a request to its token locations."""
 
@@ -158,16 +162,23 @@ class MambaPool:
                 intermediate_ssm_state_cache,
                 intermediate_conv_window_cache,
             )
+            logger.info(
+                f"Mamba Cache is allocated. "
+                f"conv_state size: {get_tensor_size_bytes(conv_state) / GB:.2f}GB, "
+                f"ssm_state size: {get_tensor_size_bytes(temporal_state) / GB:.2f}GB "
+                f"intermediate_ssm_state_cache size: {get_tensor_size_bytes(intermediate_ssm_state_cache) / GB:.2f}GB "
+                f"intermediate_conv_window_cache size: {get_tensor_size_bytes(intermediate_conv_window_cache) / GB:.2f}GB "
+            )
         else:
             self.mamba_cache = (conv_state, temporal_state)
+            logger.info(
+                f"Mamba Cache is allocated. "
+                f"conv_state size: {get_tensor_size_bytes(conv_state) / GB:.2f}GB, "
+                f"ssm_state size: {get_tensor_size_bytes(temporal_state) / GB:.2f}GB "
+            )
         self.size = size
         self.free_slots = list(range(size))
         self.mem_usage = self.get_mamba_size() / GB
-        logger.info(
-            f"Mamba Cache is allocated. "
-            f"conv_state size: {conv_state.numel() * conv_state.itemsize / GB:.2f}GB, "
-            f"ssm_state size: {temporal_state.numel() * temporal_state.itemsize / GB:.2f}GB "
-        )
 
     def get_mamba_params_all_layers(self):
         return [self.mamba_cache[i] for i in range(len(self.mamba_cache))]
@@ -176,10 +187,7 @@ class MambaPool:
         return [self.mamba_cache[i][layer_id] for i in range(len(self.mamba_cache))]
 
     def get_mamba_size(self):
-        return (
+        return sum(get_tensor_size_bytes(t) for t in self.mamba_cache)
-            np.prod(self.mamba_cache[0].shape) * self.mamba_cache[0].dtype.itemsize
-            + np.prod(self.mamba_cache[1].shape) * self.mamba_cache[1].dtype.itemsize
-        )
 
     def available_size(self):
         return len(self.free_slots)
@@ -492,10 +500,10 @@ class MHATokenToKVPool(KVCache):
         assert hasattr(self, "v_buffer")
         k_size_bytes = 0
         for k_cache in self.k_buffer:
-            k_size_bytes += np.prod(k_cache.shape) * k_cache.dtype.itemsize
+            k_size_bytes += get_tensor_size_bytes(k_cache)
         v_size_bytes = 0
         for v_cache in self.v_buffer:
-            v_size_bytes += np.prod(v_cache.shape) * v_cache.dtype.itemsize
+            v_size_bytes += get_tensor_size_bytes(v_cache)
         return k_size_bytes, v_size_bytes
 
     # for disagg
@@ -1077,7 +1085,7 @@ class MLATokenToKVPool(KVCache):
         assert hasattr(self, "kv_buffer")
         kv_size_bytes = 0
         for kv_cache in self.kv_buffer:
-            kv_size_bytes += np.prod(kv_cache.shape) * kv_cache.dtype.itemsize
+            kv_size_bytes += get_tensor_size_bytes(kv_cache)
         return kv_size_bytes
 
     # for disagg
@@ -1240,9 +1248,9 @@ class AscendMLAPagedTokenToKVPool(MLATokenToKVPool):
         assert hasattr(self, "v_buffer")
         kv_size_bytes = 0
         for k_cache in self.k_buffer:
-            kv_size_bytes += np.prod(k_cache.shape) * k_cache.dtype.itemsize
+            kv_size_bytes += get_tensor_size_bytes(k_cache)
         for v_cache in self.v_buffer:
-            kv_size_bytes += np.prod(v_cache.shape) * v_cache.dtype.itemsize
+            kv_size_bytes += get_tensor_size_bytes(v_cache)
         return kv_size_bytes
 
     def get_kv_buffer(self, layer_id: int):

python/sglang/srt/models/qwen3_next_mtp.py

@@ -85,8 +85,11 @@ class Qwen3NextForCausalLMMTP(Qwen3NextForCausalLM):
         if input_embeds is None:
             input_embeds = self.model.embed_tokens(input_ids)
 
+        hidden_states = forward_batch.spec_info.hidden_states
+        # Some idle batch has 0 batch size. GemmaRMSNorm.forward would fail due to bs=0.
+        if not forward_batch.forward_mode.is_idle():
             input_embeds = self.pre_fc_norm_embedding(input_embeds)
-        hidden_states = self.pre_fc_norm_hidden(forward_batch.spec_info.hidden_states)
+            hidden_states = self.pre_fc_norm_hidden(hidden_states)
         hidden_states = self.fc(torch.cat((input_embeds, hidden_states), dim=-1))
 
         hidden_states = self.model(