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[Bug][PD][NIXL] always send aux on is_last; only expects_state when truthy #25699

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Merged
ShangmingCai merged 2 commits into from
May 19, 2026
+22 −16
Merged

[Bug][PD][NIXL] always send aux on is_last; only expects_state when truthy #25699

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[Bug][PD][NIXL] always send aux on is_last; only expects_state when t…
ishandhanani May 18, 2026
372672c
fix lint and comment
ShangmingCai May 19, 2026
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38 changes: 22 additions & 16 deletions python/sglang/srt/disaggregation/nixl/conn.py
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Original file line number Diff line number Diff line change
Expand Up @@ -688,21 +688,24 @@ def transfer_worker(self, queue: FastQueue, staging_buffer=None):

handles.append(kv_xfer_handle)

if kv_chunk.is_last and kv_chunk.state_indices:
if kv_chunk.is_last:
dst_info = self.decode_kv_args_table[req.agent_name]
state_xfer_handles = self.maybe_send_extra(
req.agent_name,
kv_chunk.state_indices,
dst_info.dst_state_data_ptrs,
req.dst_state_indices,
dst_info.gpu_id,
f"{req.room}_state_{self.kv_args.engine_rank}",
decode_tp_size,
decode_tp_rank=dst_info.decode_tp_rank,
dst_state_item_lens=dst_info.dst_state_item_lens,
dst_state_dim_per_tensor=dst_info.dst_state_dim_per_tensor,
)
handles.extend(h for h in state_xfer_handles if h is not None)
if kv_chunk.state_indices:
state_xfer_handles = self.maybe_send_extra(
req.agent_name,
kv_chunk.state_indices,
dst_info.dst_state_data_ptrs,
req.dst_state_indices,
dst_info.gpu_id,
f"{req.room}_state_{self.kv_args.engine_rank}",
decode_tp_size,
decode_tp_rank=dst_info.decode_tp_rank,
dst_state_item_lens=dst_info.dst_state_item_lens,
dst_state_dim_per_tensor=dst_info.dst_state_dim_per_tensor,
)
handles.extend(
h for h in state_xfer_handles if h is not None
)

if kv_chunk.prefill_aux_index is None:
raise RuntimeError("Missing aux index for last chunk")
Expand Down Expand Up @@ -1974,8 +1977,11 @@ def send_metadata(
]
)

# Mark that we expect state data if state_indices was provided
if state_indices is not None:
# Mark that we expect state data if state_indices was provided.
# Match the prefill-side truthy check: an empty list means the
# model has no state types (e.g. dense LLaMA/Qwen), and prefill
# won't send state notifs, so we must not expect them.
if state_indices:
self.kv_mgr.transfer_statuses[self.bootstrap_room].expects_state = True

self.started_transfer = True
Expand Down
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