lading-optimize-find-target

## Phase 1: Discover Benchmark-Eligible Modules A module is eligible if it has a Criterion benchmark in `lading_payload/benches/`. 1. **List benchmarks**: Glob `lading_payload/benches/*.rs` — each filename (minus `.rs`) is a bench name 2. **Resolve sources**: For each bench name, find the corresponding source file(s) under `lading_payload/src/`. Check single-file modules (`{name}.rs`), directory modules (`{name}/`), and parent-module patterns (e.g., `opentelemetry_log` → `opentelemetry/log.rs`) 3. **Match fingerprints**: Glob `ci/fingerprints/*/lading.yaml` — each directory name is a fingerprint. Match fingerprints to modules by reading the `variant:` key from each config The result is a set of `(bench, source_files, fingerprint_or_none)` triples. --- ## Phase 2: Profile Allocation Intensity Run the profiling script: ```bash .claude/skills/lading-optimize-find-target/scripts/profile-modules ``` Output is TSV: `module, allocations, total_bytes, peak_live_bytes`. Record per-module. --- ## Phase 3: Learn from Past Optimizations Read the optimization history to understand what techniques work and what's already done: ``` Read .claude/skills/lading-optimize-hunt/assets/db.yaml ``` For each entry, read its detail file (`file:` field, relative to `.claude/skills/lading-optimize-hunt/`) to extract: - **Technique and measurements** — which techniques yielded what % improvements - **Lessons** — what patterns were optimized and what the before/after looked like - **Targets already covered** — so you skip them This history teaches you what to look for. Successful past techniques are strong signals for where to look next. The `lessons` field often suggests next targets explicitly. --- ## Phase 4: Find Opportunities Scan **every** benchmark-eligible source module for **every** known pattern below. This is an exhaustive cross-product — do not short-circuit after finding one hit. ### Known Patterns | Name | Pattern | Technique | | ------------------------- | --------------------------------- | ---------------------------------- | | `vec-with-capacity` | `Vec::new()` + repeated push | `Vec::with_capacity(n)` | | `string-with-capacity` | `String::new()` + repeated push | `String::with_capacity(n)` | | `map-with-capacity` | `FxHashMap::default()` hot insert | `FxHashMap::with_capacity(n)` | | `buffer-reuse` | `format!()` in hot loop | `write!()` to reused buffer | | `slice-params` | `&Vec<T>` or `&String` parameter | `&[T]` or `&str` slice | | `hoist-allocation` | Allocation in hot loop | Move allocation outside loop | | `object-pool` | Repeated temp allocations | Object pool / buffer reuse | | `borrow-not-clone` | Clone where borrow works | Use reference | | `inline` | Hot cross-crate fn call | `#[inline]` attribute | | `lazy-iterators` | Intermediate `.collect()` calls | Iterator chains without collect | | `box-large-structs` | Large struct by value | Box or reference | | `bounded-buffer` | Unbounded growth | Bounded buffer with `.clear()` | | `scratch-buffer` | `encode_to_vec()` per call | Reusable `BytesMut` scratch buffer | | `on-demand-serialization` | Deep clone of template in loop | Incremental mutation / COW | ### Procedure (must follow exactly) **Step 1 — Read source files.** For each module's source file(s), Read the full file (excluding `#[cfg(test)]` blocks). Understand the data flow: what structs exist, how serialization works, where the hot path is, and what allocations occur. **Step 2 — Identify patterns.** For each module, check whether any of the Known Patterns above apply. Record a hit matrix: ``` module × pattern → match count (0 = no hit) ``` Show the full matrix as a table. Every cell must have a value. Do NOT skip any combination. **Step 3 — Record opportunities.** Each verified hot-path hit becomes an opportunity: `(pattern, technique, target_function, file, module, allocations_from_profiling)` --- ## Phase 5: Filter Remove any opportunity that: 1. **Already in `.claude/skills/lading-optimize-hunt/assets/db.yaml`** — same function + semantically equivalent technique already exists 2. **No benchmark** — module has no matching bench file in `lading_payload/benches/` If zero survive, STOP: "No valid optimization targets found." --- ## Phase 6: Rank Sort by two dimensions: 1. **Technique impact** — techniques with measured history in `.claude/skills/lading-optimize-hunt/assets/db.yaml` rank higher (compute avg % improvement from `measurements.benchmarks.macro`). Unknown techniques rank last. 2. **Allocation intensity** — modules with higher allocation counts from profiling rank higher. Sort by technique impact first, allocation intensity second. **Tiebreaker:** Prefer modules with no prior `.claude/skills/lading-optimize-hunt/assets/db.yaml` entries, then alphabetical file name. Show sorted results in a table. --- ## Phase 7: Return Result Pick the top-ranked opportunity. Return as a fenced YAML code block. **Do NOT write to disk.** **Do not include intermediate tables, matrices, or analysis.** ```yaml pattern: "<description of the code pattern found>" technique: "<pattern name / optimization technique to apply>" target: "<Module::function>" file: "<relative path to source file>" bench: "<relative path to Criterion benchmark .rs file>" fingerprint: "<relative path to fingerprint lading.yaml config, or null>" ``` ---