Phase8 only gains useful overlap when the next-layer MLA prefix prefetch is allowed to run until the next layer actually consumes the prefetched buffer. The old wait-after-attention switch let runtime configuration collapse the optimization back into current-layer tail latency, so the prefetch path now has one wait policy and the documentation records the implemented behavior.
Constraint: Phase8 should keep the production environment surface minimal while preserving the existing enable and debug-log knobs
Rejected: SGLANG_CP_SHARED_KV_MLA_PREFETCH_WAIT_AFTER_ATTENTION | it reintroduced current-layer synchronous waiting and made profiling behavior depend on a nonessential policy knob
Confidence: medium
Scope-risk: narrow
Directive: Do not add another Phase8 wait policy knob without first proving the added policy improves end-to-end prefill latency under CP shared KV
Tested: Python AST parse for touched Python files
Tested: git diff --check
Not-tested: Full pytest and remote server integration were not run in this commit
9fec89ba09