From 201ddeaba1462504d1fb7384436f843b530a4a54 Mon Sep 17 00:00:00 2001
From: fzyzcjy <5236035+fzyzcjy@users.noreply.github.com>
Date: Wed, 15 Jul 2026 14:33:37 +0800
Subject: [PATCH] Avoid relaying per-step outputs through ScheduleBatch fields
 in disagg prefill and PP (#30677)

---
 python/sglang/srt/disaggregation/prefill.py      | 10 ++++++----
 python/sglang/srt/managers/scheduler_pp_mixin.py |  6 +++---
 2 files changed, 9 insertions(+), 7 deletions(-)

diff --git a/python/sglang/srt/disaggregation/prefill.py b/python/sglang/srt/disaggregation/prefill.py
index d8036d36f..7892ac940 100644
--- a/python/sglang/srt/disaggregation/prefill.py
+++ b/python/sglang/srt/disaggregation/prefill.py
@@ -620,6 +620,8 @@ class SchedulerDisaggregationPrefillMixin:
             result.indexer_topk_output = None
 
         logprob_pt = 0
+        assert batch.spec_info is result.next_draft_input
+        draft_input = result.next_draft_input
         # Transfer kv for prefill completed requests and add it into disagg_prefill_inflight_queue
         next_token_ids = result.next_token_ids.tolist()
         self.batch_result_processor.move_logprobs_to_cpu(
@@ -651,11 +653,11 @@ class SchedulerDisaggregationPrefillMixin:
                 req.output_ids.append(next_token_id)
                 maybe_cache_unfinished_req(req, self.tree_cache)
                 self.disagg_prefill_inflight_queue.append(req)
-                if self.spec_algorithm.is_eagle() and batch.spec_info is not None:
-                    req.output_topk_p = batch.spec_info.topk_p[i]
-                    req.output_topk_index = batch.spec_info.topk_index[i]
+                if self.spec_algorithm.is_eagle() and draft_input is not None:
+                    req.output_topk_p = draft_input.topk_p[i]
+                    req.output_topk_index = draft_input.topk_index[i]
                     req.hidden_states_tensor = (
-                        batch.spec_info.hidden_states[i].cpu().clone()
+                        draft_input.hidden_states[i].cpu().clone()
                     )
                     dsa_topk_indices = batch.spec_info.dsa_topk_indices
                     if dsa_topk_indices is not None:
diff --git a/python/sglang/srt/managers/scheduler_pp_mixin.py b/python/sglang/srt/managers/scheduler_pp_mixin.py
index 30b5bf43e..ff440de77 100644
--- a/python/sglang/srt/managers/scheduler_pp_mixin.py
+++ b/python/sglang/srt/managers/scheduler_pp_mixin.py
@@ -1101,7 +1101,6 @@ class SchedulerPPMixin:
         # next_pp_outputs = None so non-last ranks skip forwarding
         # (pp_outputs is None gate). Placeholder carried in
         # batch_result.next_token_ids for process_batch_result_prefill.
-        batch.output_ids = placeholder
         batch_result = GenerationBatchResult(
             logits_output=None,
             pp_hidden_states_proxy_tensors=None,
@@ -1133,13 +1132,14 @@ class SchedulerPPMixin:
                 extend_input_len_per_req,
                 extend_logprob_start_len_per_req,
             ) = get_logprob_from_pp_outputs(pp_outputs)
-        batch.input_ids = pp_outputs["next_token_ids"].to(torch.int64)
+        next_token_ids = pp_outputs["next_token_ids"].to(torch.int64)
         # PP rank 0 also relays into output_tokens_buf so the next iter's
         # resolve_forward_inputs finds these tokens for the decode portion
         # of mixed-chunk batches (which gather via mix_running_indices).
         self.future_map.stash(
-            batch.req_pool_indices, RelayPayload(bonus_tokens=batch.input_ids)
+            batch.req_pool_indices, RelayPayload(bonus_tokens=next_token_ids)
         )
+        batch.input_ids = None
         output_result = GenerationBatchResult(
             logits_output=logits_output,
             pp_hidden_states_proxy_tensors=None,