The official source reports this update: b10731: qwen4exp: support recurrent state rollback. qwen4exp: support recurrent state rollback ( #28123 ) MTP speculative decoding needs the target state to move back by the number of rejected draft tokens. Without rollback support the context is classified as SEQ_RM_TYPE_FULL and the server serializes the whole recurrent state to host memory on every round, which costs more than the drafting saves. The recurrent cache already holds n_rs_seq + 1 snapshot planes and the delta net writes its SSM state into them, but build_conv_state_at wrote a single plane, so a rollback restored a convolution history that was never captured.
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Qwen4exp adds recurrent state rollback for faster decoding.
The recurrent state rollback feature improves decoding speed to 183 tok/s on code and 144 tok/s on prose.
2 Sept 20261 verified claims1 sources1 observations
This official update documents a development concerning b10731: qwen4exp: support recurrent state rollback. Its practical significance depends on the scope and evidence stated by the source.
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