[PD-Disagg] Fully support external DP dispatch w/ PD-disaggregation mode. (#19268)

Co-authored-by: Ratish P <114130421+ratish1@users.noreply.github.com>

python/sglang/srt/disaggregation/decode.py

@@ -355,15 +355,15 @@ class DecodePreallocQueue:
             req.retraction_mb_id = None
             self.retracted_queue.append(req)
         else:
-            dp_rank = self._resolve_dp_rank(req)
-            if dp_rank is None:
+            prefill_dp_rank = self._resolve_prefill_dp_rank(req)
+            if prefill_dp_rank is None:
                 self.pending_reqs.append(req)
                 return
-            self._create_receiver_and_enqueue(req, dp_rank)
+            self._create_receiver_and_enqueue(req, prefill_dp_rank)
 
-    def _resolve_dp_rank(self, req: Req) -> Optional[int]:
-        if req.data_parallel_rank is not None:
-            return req.data_parallel_rank
+    def _resolve_prefill_dp_rank(self, req: Req) -> Optional[int]:
+        if req.disagg_prefill_dp_rank is not None:
+            return req.disagg_prefill_dp_rank
 
         if _is_fake_transfer(req, self.scheduler.server_args):
             return 0
@@ -379,7 +379,7 @@ class DecodePreallocQueue:
 
         return None
 
-    def _create_receiver_and_enqueue(self, req: Req, dp_rank: int) -> None:
+    def _create_receiver_and_enqueue(self, req: Req, prefill_dp_rank: int) -> None:
         backend = (
             TransferBackend.FAKE
             if _is_fake_transfer(req, self.scheduler.server_args)
@@ -391,7 +391,7 @@ class DecodePreallocQueue:
             mgr=self.kv_manager,
             bootstrap_addr=f"{req.bootstrap_host}:{req.bootstrap_port}",
             bootstrap_room=req.bootstrap_room,
-            prefill_dp_rank=dp_rank,
+            prefill_dp_rank=prefill_dp_rank,
         )
 
         self.queue.append(
@@ -493,16 +493,16 @@ class DecodePreallocQueue:
                 raise ValueError(f"Unexpected poll case: {poll}")
 
     def _resolve_pending_reqs(self) -> None:
-        """Batch-resolve dp_ranks for pending requests and create receivers."""
+        """Batch-resolve prefill_dp_ranks for pending requests and create receivers."""
         if not self.pending_reqs:
             return
 
         bootstrap_addr = f"{self.pending_reqs[0].bootstrap_host}:{self.pending_reqs[0].bootstrap_port}"
 
         # If a request is following the bootstrap room,
-        # we need get the prefill info before resolving the dp_rank,
+        # we need get the prefill info before resolving the prefill_dp_ranks
         # which is a conflict with the lazy resolve logic in CommonKVReceiver,
-        # so we need to ensure the parallel info before resolving the dp_rank
+        # so we need to ensure the parallel info before resolving it.
         if not self.kv_manager.ensure_parallel_info(bootstrap_addr):
             return
 
@@ -510,9 +510,9 @@ class DecodePreallocQueue:
         need_query = []
         for req in self.pending_reqs:
             # NOTE: we need resolve it again because we may ensure the parallel info here
-            dp_rank = self._resolve_dp_rank(req)
-            if dp_rank is not None:
-                resolved.append((req, dp_rank))
+            prefill_dp_rank = self._resolve_prefill_dp_rank(req)
+            if prefill_dp_rank is not None:
+                resolved.append((req, prefill_dp_rank))
             else:
                 need_query.append(req)
 
@@ -534,8 +534,8 @@ class DecodePreallocQueue:
         else:
             self.pending_reqs = []
 
-        for req, dp_rank in resolved:
-            self._create_receiver_and_enqueue(req, dp_rank)
+        for req, prefill_dp_rank in resolved:
+            self._create_receiver_and_enqueue(req, prefill_dp_rank)
 
     def pop_preallocated(
         self, rids_to_check: Optional[List[str]] = None

python/sglang/srt/disaggregation/encode_receiver.py

@@ -341,7 +341,7 @@ class MMReceiverHTTP(MMReceiverBase):
                     skip_mm_pool=True,
                 )
 
-    def create_req(self, recv_req):
+    def create_req(self, recv_req: TokenizedGenerateReqInput):
         req = Req(
             recv_req.rid,
             recv_req.input_text,
@@ -362,7 +362,8 @@ class MMReceiverHTTP(MMReceiverBase):
             bootstrap_port=recv_req.bootstrap_port,
             bootstrap_room=recv_req.bootstrap_room,
             disagg_mode=self.scheduler.disaggregation_mode,
-            data_parallel_rank=recv_req.data_parallel_rank,
+            routed_dp_rank=recv_req.routed_dp_rank,
+            disagg_prefill_dp_rank=recv_req.disagg_prefill_dp_rank,
             vocab_size=self.scheduler.model_config.vocab_size,
             priority=recv_req.priority,
             metrics_collector=(