Support GC Freezing to improve latency & throughput (#9241)

Co-authored-by: Chanh Nguyen <cnguyen@linkedin.com>
Co-authored-by: Liangsheng Yin <hnyls2002@gmail.com>

python/sglang/srt/managers/detokenizer_manager.py

@@ -31,10 +31,12 @@ from sglang.srt.managers.io_struct import (
     BatchMultimodalOut,
     BatchStrOut,
     BatchTokenIDOut,
+    FreezeGCReq,
 )
 from sglang.srt.server_args import PortArgs, ServerArgs
 from sglang.srt.utils import (
     configure_logger,
+    freeze_gc,
     get_zmq_socket,
     kill_itself_when_parent_died,
 )
@@ -100,6 +102,7 @@ class DetokenizerManager:
                 (BatchEmbeddingOut, self.handle_batch_embedding_out),
                 (BatchTokenIDOut, self.handle_batch_token_id_out),
                 (BatchMultimodalDecodeReq, self.handle_multimodal_decode_req),
+                (FreezeGCReq, self.handle_freeze_gc_req),
             ]
         )
 
@@ -108,7 +111,8 @@ class DetokenizerManager:
         while True:
             recv_obj = self.recv_from_scheduler.recv_pyobj()
             output = self._request_dispatcher(recv_obj)
-            self.send_to_tokenizer.send_pyobj(output)
+            if output is not None:
+                self.send_to_tokenizer.send_pyobj(output)
 
     def trim_matched_stop(
         self, output: Union[str, List[int]], finished_reason: Dict, no_stop_trim: bool
@@ -247,6 +251,10 @@ class DetokenizerManager:
             cached_tokens=recv_obj.cached_tokens,
         )
 
+    def handle_freeze_gc_req(self, recv_req: FreezeGCReq):
+        freeze_gc("Detokenizer Manager")
+        return None
+
 
 class LimitedCapacityDict(OrderedDict):
     def __init__(self, capacity: int, *args, **kwargs):