DP: support piggyback server load report (#11469)

Signed-off-by: Chang Huaixin (OpenAnolis) <changhuaixin@linux.alibaba.com>

python/sglang/srt/managers/scheduler_output_processor_mixin.py

@@ -299,6 +299,18 @@ class SchedulerOutputProcessorMixin:
 
         return predict_tokens
 
+    def process_batch_result_idle(
+        self: Scheduler,
+        batch: ScheduleBatch,
+        result: GenerationBatchResult,
+    ):
+        if result.copy_done is not None:
+            result.copy_done.synchronize()
+
+        self.stream_output_generation(
+            batch.reqs, batch.return_logprob, is_idle_batch=True
+        )
+
     def process_batch_result_dllm(
         self: Scheduler,
         batch: ScheduleBatch,
@@ -790,6 +802,7 @@ class SchedulerOutputProcessorMixin:
         reqs: List[Req],
         return_logprob: bool,
         skip_req: Optional[Req] = None,
+        is_idle_batch: bool = False,
     ):
         rids = []
         http_worker_ipcs = []
@@ -810,6 +823,7 @@ class SchedulerOutputProcessorMixin:
         spec_accepted_tokens = []
         retraction_counts = []
         output_hidden_states = None
+        load = self.get_load()
         output_routed_experts = None
 
         queue_times = []
@@ -1018,7 +1032,7 @@ class SchedulerOutputProcessorMixin:
                 req.log_time_stats()
 
         # Send to detokenizer
-        if rids:
+        if reqs or is_idle_batch:
             if self.model_config.is_multimodal_gen:
                 return
 
@@ -1062,6 +1076,7 @@ class SchedulerOutputProcessorMixin:
                     placeholder_tokens_idx=None,
                     placeholder_tokens_val=None,
                     retraction_counts=retraction_counts,
+                    load=load,
                 )
             )