docs(research): step 3b -- AVX2 check against the new evaluator (owner's request)

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01MmSoF64BbRFmk9C3p1VsBJ

RESEARCH-SPEED-2026-09.md

@@ -34,6 +34,7 @@ The steps below describe **future plugin experiments**. This research pass makes
 1. **Day-one falsification: stage the existing collision and upload clocks.** Add timestamps for collision request, RMC end-of-frame dequeue, `GThreadPool` worker start, geometry extraction end, `CookComplexMesh` start/end, game-thread `ApplyCollisionUpdate` start/end, physics-state ready and first successful capsule sweep. Keep existing generation, mesh and gameplay behavior while profiling. Test one ~4,000-triangle tile and the pawn's current 3³=27-tile support neighborhood, idle at the current 14 generation tasks, and with the generation cap reduced to 12. If the cook's queue wait dominates, test a dedicated priority cook dispatched directly after player-support mesh extraction; compare its core cook and install times with RMC's route. In parallel, prequeue a 341-tile render corpus and run caps 4/8/16 with the same 2 ms drain guard; record visible applies/s, game/render/RHI clocks and first-visible frame. **Pass the cook shortcut only if** core cook p95 ≤10 ms, the 27-tile player support is ready ≤150 ms after meshes exist under load, and an edit-time field override can switch floor/support within the first simulated/rendered frame with zero invented velocity in 100 repeated underfoot digs. If any edit test fails, implement field-aware Mover as the player authority; if the shortcut passes all tests, use prioritized cooks for steady terrain plus field queries while an edit's cook is pending. **Pass the ungrouped upload path only if** it sustains ≥525 visible applies/s at 60 Hz with game-thread drain ≤2 ms/frame and no render/RHI backlog. These are decision thresholds, not existing measurements.
 2. **Standalone exact-float evaluator ablation.** Extract representative *real* TunnelNetwork and composer plans, including warped rooms, passages, stratum transitions, route floors and diff edits, into `Saved/Research` only. Keep the plugin's active evaluator and worlds untouched. Compare baseline point API to a prepared float region/brick API at the same lattice coordinates and op order. The reference is the chosen **new-world float definition**, not old-season geometry. **Pass:** zero 16-bit quantized-value disagreements and zero route/capsule regression across at least five seeds; ≤**600 ms** for the full 259³ cold ring on six workers before certificates. Record candidate visits, cache checks and worker CPU. Failure means local compilation did not remove enough work; investigate before rewriting numeric math.
 3. **Add certificates, shared lattice and contouring.** Prove final-sign bounds after all writers and edits; classify 8³ bricks, evaluate uncertain ones, share global corners, and mesh them with today's marching-cubes table. Keep the old tile route as a versioned reference while the new route is validated. **Pass:** zero false-uniform bricks and zero sign mismatch at all 17,373,979 ring lattice sites for the test corpus, cold worker generation ≤**350 ms**, and max render-visible/full ring ≤**900 ms** in the later UE gate. If certification consumes more time than it saves, fall back to evaluating uncertain regions without that proof; do not repeat the archived 0.588→2.057 s interval-control mistake.
+3b. **AVX2 check against the new norm (owner's request, 2026-09-29).** Once step 3's brick evaluator is the baseline, try an explicit 8-lane AVX2 version of its hot loop (the plugin's current noise path is 4-lane SSE4.1). Float lanes stay deterministic only with no FMA contraction and each lane performing exactly the scalar op sequence. **Keep it only if** it is faster on the step-3 corpus and the quantized lattice hash is identical to the scalar path on two runs; otherwise record the number and drop it. The round-two integer AVX2 probe (4.25–5.86× over its own scalar) is the reference for what explicit vectorisation can buy.
 4. **Choose and implement player collision.** Use step 1 to select prioritized Chaos+edit overlay or field-aware Mover; keep ordinary collision with nonterrain actors and keep NPC/projectile field-query backup. Version floor/contact state by edit sequence. **Pass:** at every teleport the player can perform an actual blocked capsule movement on the intended terrain ≤**900 ms** after the request, 100 underfoot digs add **0** spurious velocity impulses, and 100 excavations with no cave below have **0** frames of false support or false air. The full visible ring must also meet the separate ≤1,000 ms hard deadline. A successful cook timing without the edit tests is insufficient.
 5. **Decide render batching from measured throughput.** Keep per-tile RMC if it sustains ≥525 visible applies/s and the first-visible gate ≤900 ms. Otherwise group 2³ tiles per page while retaining tile-addressable sections and the same materials/LOD transition topology; rerun the same corpus and require ≥**99 page applies/s** for at most 64 pages in 0.65 s, ≤2 ms/frame game-thread drain and no render-thread tail past the 1 s deadline. If grouping causes whole-page reupload on small edits or still misses, use a dedicated batched render proxy. Compare first-visible time against the same ≤900 ms gate.
 6. **Version the edit and GPU visual protocol.** Quantize float-produced lattice density with specified rounding/saturation; use fixed integer edit composition, stable per-cell triangle counts/prefix sums, global edge ownership and one edit sequence across touched pages/LODs. Keep CPU procedural generation, composer, route graph and ordered edit replication as the authority. Test AMD and NVIDIA output hashes against CPU reference; on a single machine, two full cold runs must yield the **same field/sign/mesh hash**. **Pass:** a radius-10 m crater (up to 714 bricks/64 tiles) appears throughout its region in the **first submitted render frame containing the edit**, no gap/ghost/ripple at borders or LOD seams, CPU/GPU sign disagreement **0**, and added GPU cost ≤**2 ms** within an 11.1 ms 90 Hz VR frame in 20 varied positions. If direct GPU remeshing exceeds that, test the complete-region raymarch overlay with the same visual and frame gates; do not publish a partial mesh.