Tiny add Engine.flush_cache API (#5241)

python/sglang/srt/managers/io_struct.py

@@ -671,10 +671,15 @@ class BatchEmbeddingOut:
 
 
 @dataclass
-class FlushCacheReq:
+class FlushCacheReqInput:
     pass
 
 
+@dataclass
+class FlushCacheReqOutput:
+    success: bool
+
+
 @dataclass
 class UpdateWeightFromDiskReqInput:
     # The model path with the new weights

python/sglang/srt/managers/scheduler.py

@@ -60,7 +60,8 @@ from sglang.srt.managers.io_struct import (
     CloseSessionReqInput,
     ExpertDistributionReq,
     ExpertDistributionReqOutput,
-    FlushCacheReq,
+    FlushCacheReqInput,
+    FlushCacheReqOutput,
     GetInternalStateReq,
     GetInternalStateReqOutput,
     GetWeightsByNameReqInput,
@@ -402,7 +403,7 @@ class Scheduler(
             [
                 (TokenizedGenerateReqInput, self.handle_generate_request),
                 (TokenizedEmbeddingReqInput, self.handle_embedding_request),
-                (FlushCacheReq, self.flush_cache_wrapped),
+                (FlushCacheReqInput, self.flush_cache_wrapped),
                 (AbortReq, self.abort_request),
                 (OpenSessionReqInput, self.open_session),
                 (CloseSessionReqInput, self.close_session),
@@ -1596,8 +1597,9 @@ class Scheduler(
         time.sleep(5)
         self.parent_process.send_signal(signal.SIGQUIT)
 
-    def flush_cache_wrapped(self, recv_req: FlushCacheReq):
-        self.flush_cache()
+    def flush_cache_wrapped(self, recv_req: FlushCacheReqInput):
+        success = self.flush_cache()
+        return FlushCacheReqOutput(success=success)
 
     def flush_cache(self):
         """Flush the memory pool and cache."""

python/sglang/srt/managers/tokenizer_manager.py

@@ -66,7 +66,8 @@ from sglang.srt.managers.io_struct import (
     EmbeddingReqInput,
     ExpertDistributionReq,
     ExpertDistributionReqOutput,
-    FlushCacheReq,
+    FlushCacheReqInput,
+    FlushCacheReqOutput,
     GenerateReqInput,
     GetInternalStateReq,
     GetInternalStateReqOutput,
@@ -264,6 +265,9 @@ class TokenizerManager:
         self.resume_memory_occupation_communicator = _Communicator(
             self.send_to_scheduler, server_args.dp_size
         )
+        self.flush_cache_communicator = _Communicator(
+            self.send_to_scheduler, server_args.dp_size
+        )
         self.start_profile_communicator = _Communicator(
             self.send_to_scheduler, server_args.dp_size
         )
@@ -314,6 +318,10 @@ class TokenizerManager:
                     ResumeMemoryOccupationReqOutput,
                     self.resume_memory_occupation_communicator.handle_recv,
                 ),
+                (
+                    FlushCacheReqOutput,
+                    self.flush_cache_communicator.handle_recv,
+                ),
                 (
                     ProfileReqOutput,
                     self.start_profile_communicator.handle_recv,
@@ -707,9 +715,8 @@ class TokenizerManager:
                     except StopAsyncIteration:
                         pass
 
-    def flush_cache(self):
-        req = FlushCacheReq()
-        self.send_to_scheduler.send_pyobj(req)
+    async def flush_cache(self) -> FlushCacheReqOutput:
+        return await self.flush_cache_communicator(FlushCacheReqInput())
 
     def abort_request(self, rid: str):
         if rid not in self.rid_to_state: