perf(orchestration): cache forward adjacency in CascadeDetector#3114
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perf(orchestration): cache forward adjacency in CascadeDetector#3114
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Add a lazily-built `forward_adjacency: Option<Vec<Vec<TaskId>>>` field to `CascadeDetector`. `ensure_adjacency` builds the dense index once per DAG lifetime and is invalidated exclusively in `reset()`, which is called from `inject_tasks` — the only production mutation path. `descendant_count` (called once per task per tick in `deprioritized_tasks` when cascade routing is active) no longer rebuilds a `HashMap` on every invocation. For diamond/fan-in DAGs the per-tick cost drops from O(K*(N+E)) to O(N*R*D) where D is the subtree size. Public methods `is_cascading`, `deprioritized_tasks`, and `evaluate_abort` become `&mut self` to carry the cache. A `#[cfg(test)]` accessor `forward_adjacency_is_cached` mirrors the existing `region_health` pattern. Closes #3094
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Summary
forward_adjacency: Option<Vec<Vec<TaskId>>>cache toCascadeDetectordescendant_count(called per-task per-tick indeprioritized_tasks) no longer rebuilds aHashMapon every invocation — the dense index is built once per DAG lifetime and invalidated inreset()is_cascading,deprioritized_tasks, andevaluate_abortbecome&mut self; two scheduler call-sites updatedChanges
crates/zeph-orchestration/src/cascade.rs— cache field,ensure_adjacency,reset()invalidation, accessor, doc invariantcrates/zeph-orchestration/src/scheduler.rs—ref→ref mutat two call-sites, pre-binding borrow fix at :1457CHANGELOG.md—[Unreleased]Performance entryTest plan
cargo +nightly fmt --check— cleancargo clippy --workspace -- -D warnings— cleancargo nextest run --config-file .github/nextest.toml --workspace --lib --bins— 8175/8175 passreset()Closes #3094