streaming: far LODs keep a share while near work is pending (L79); no more horizon starvation

L78's strict near-first order starved far LODs at 30 m/s (100% far holes, never completed).
Unreal policy 2: once the collision ring is ready, LOD0-2 keep their reserve and far tiles are
admitted as low-priority Horizon work; headless gives far work 1 of every 16 requests.
Moving camera, far holes while moving: 1.4 m/s L77 8% / L78 29% / L79 31%; 30 m/s L77 8% /
L78 100% / L79 72% (completes on dwell). Near readiness while moving at 30 m/s: 52 / 51 / 67%.
Still worse than L77 for fast travel -> speed-adaptive policy next. World unchanged (v213).
Fast tier PASS; Linux UE host builds.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_016dhxM43dnWvUu2B5Ph1iG1

Standalone/Research/WorldAssemblerM3/Linux79/REPORT.md

@@ -0,0 +1,67 @@
+# Linux79 report
+
+## Moving-camera starvation
+
+The UE scheduler now defaults to policy 2: once the collision-critical ring is ready, LOD0–2 keep their reserved admission budget and far tiles are admitted as low-priority `Horizon` work. It no longer waits for every near tile before admitting far work. The headless policy uses a recurring far share (one far request per 16 near requests). Generation stays on workers.
+
+The headless trace moved for 12 s, then dwelled for 5 s at 1.4 m/s and 30 m/s. Each run had 69 samples, 8 workers, and zero generation failures. Headless processes were pinned to CPUs 0–11, address-space limited to 6 GiB, and capped at 1,740 s. “Far holes” counts desired far tiles with neither their LOD nor a resident coarser parent. Near readiness is the moving-sample mean; dwell ended with near readiness at 100% in every run.
+
+| Speed | Order | All far ready | Moving far holes, mean | Max far stale age | Moving near ready, mean | Dwell far holes |
+|---|---|---:|---:|---:|---:|---:|
+| 1.4 m/s | L77 coarse-first | 1.50 s | 8.25% | 1.25 s | 73.73% | 0% |
+| 1.4 m/s | L78 strict near-first | 4.00 s | 29.20% | 3.75 s | 85.03% | 0% |
+| 1.4 m/s | L79 fair share | 4.25 s | 30.79% | 4.00 s | 82.90% | 0% |
+| 30 m/s | L77 coarse-first | 1.75 s | 8.16% | 1.25 s | 52.14% | 0% |
+| 30 m/s | L78 strict near-first | Never | 100.00% | 17.00 s | 51.40% | 100% |
+| 30 m/s | L79 fair share | 9.75 s | 71.89% | 9.50 s | 66.67% | 0% |
+
+Verdict: L78 starves the horizon at 30 m/s, including through the dwell. L79 prevents indefinite starvation and finishes far coverage while still moving, but far coverage remains sparse during fast travel. L77 has much better far coverage and faster far completion, while L79 improves near readiness at 30 m/s. At walking speed L79 is close to L78. L79 is the near-priority/far-progress compromise; it does not provide L77-level moving coverage.
+
+Trace summary and samples: `Saved/Linux/l79/movement/headless/summary.json` and `samples.csv`; per-policy logs are alongside them.
+
+## Passage-cost decision
+
+I tested a point-bound filter candidate against the same page route on 32 tiles (8 per strate: four LOD0 and four LOD1). Across 42,875 density samples per tile it changed zero samples and zero signs. Maximum and mean surface displacement were both 0 cm; solid/air membership did not change, and there were no changed samples at mouths or within 4 m of walls. There were consequently no changed tiles to classify as mouth or wall losses.
+
+The candidate did not reduce passage work: candidate/base median tile-time ratios were SW 1.002, FI 1.014, TN 0.990, and VS 0.993. All inspected pairs also reported zero baseline and candidate segment visits, so this sample set is a negative control and does not validate bounds on an active passage-wall sample. I rejected the candidate: it showed no useful performance gain, and it is not accepted as proof that the larger passage cuts are safe. No field change or evaluator-version bump was made; the passage cost remains open.
+
+The broad L76 cut remains rejected (612 density mismatches; mesh, payload, and topology changed on 24 tiles). Its retained artifacts contain aggregate hash counts, not per-sample deltas, so this round does not claim to have inspected those individual changes. The L79 candidate’s per-tile evidence is in `Saved/Linux/l79/passage-bounds/{0-SurfaceWorld,1-FloatingIslands,2-TunnelNetwork,3-VerticalShafts}.log`.
+
+No new mouth or mid-tunnel capture set was made because no passage geometry change was accepted. The final fast tier’s existing passage audits passed, including support, capsule/walkability, grade/floor, ripple, naturalness, route binding, and mouth-profile gates.
+
+## Readiness, W8, three interleaved pairs, median seconds
+
+| Strate | L78 LOD0–2 | L79 LOD0–2 | L78 whole view | L79 whole view |
+|---|---:|---:|---:|---:|
+| SurfaceWorld | 1.232 | 1.365 | 2.762 | 2.611 |
+| FloatingIslands | 3.391 | 3.503 | 4.881 | 4.763 |
+| TunnelNetwork | 3.363 | 3.737 | 4.621 | 4.792 |
+| VerticalShafts | 1.417 | 1.683 | 2.615 | 2.603 |
+
+L79 trades a small near-readiness regression for guaranteed far admission. The L77 sampler census from the L78 before/after pair set is retained here; B/A are before/after the exact composer trims. “Near” means LOD0–2.
+
+| Strate | Near grid-fill closure B/A | Whole closure B/A | Passage CPU share B/A | Support CPU share B/A |
+|---|---:|---:|---:|---:|
+| SurfaceWorld | 99.1% / 99.9% | 100.1% / 99.6% | 45.1% / 47.6% | 15.0% / 12.8% |
+| FloatingIslands | 99.9% / 99.5% | 99.8% / 99.8% | 64.6% / 63.0% | 14.1% / 13.8% |
+| TunnelNetwork | 99.9% / 100.1% | 99.8% / 100.2% | 65.9% / 63.7% | 13.2% / 13.5% |
+| VerticalShafts | 100.0% / 100.2% | 99.9% / 100.9% | 45.9% / 42.9% | 5.9% / 6.6% |
+
+Timing data: `Saved/Linux/l79/timing/summary.json`. Sampler source data: `Saved/Linux/l78/{sampler-census,closure-census,route-census}.csv`; sampler handler cost stayed below 0.05% of profiled thread CPU.
+
+## Version, hashes, and verification
+
+- `WorldAssemblyEvaluatorVersion=213`; unchanged. The passage candidate was removed, so no geometry or world-hash update was accepted.
+- `Standalone/data/owner_world.json` SHA256: `38b3d3085f2a0711a7c8dbe8883aaaf2510a9acbfb529ebece6de6d8c2dbfde`.
+- Final source stamp: `084e7beed3039198b633d0075793f14796fdd7628b307406f6fdda7aedab641a`.
+- Fast tier: PASS, 274 checks, 332.3 s. Passage audits and Clang W1/W8/W12 determinism checks passed. Clang and GCC binaries built at the final source stamp; no L79 GCC W1/W8/W12 matrix or new passage captures were run because no geometry change was accepted. Clang headless SHA256 `f67c58b3b60bf41bcdb630f82afee5b87a57c3b991dad3dbb4e93523032c9229`; GCC `faf139e63a7eff5c27f898bef508240ae602b63d9e509bc512dec71118fe4fe3`.
+- Linux `VFHostEditor` build after timing: PASS in 81.49 s, `taskset -c 0-11`, `-MaxParallelActions=4`, no address-space limit. Three existing RealtimeMesh deprecation warnings. The only changed `Source/` file is `Source/VoxelForge/Private/VoxelWorld.cpp`; UBT compiled it and the VFCore amalgam. Log: `Saved/Linux/l79/build/ue-host-build-final.log`.
+
+## Failed runs
+
+- Three Unreal null-RHI moving-trace attempts exited during asset load at the 6 GiB address-space cap (`Ran out of memory allocating 5,096,960 bytes`). The permitted headless moving-camera traces supplied the comparison instead.
+- The first headless movement diagnostic segfaulted after generator release because it updated desired tiles without the camera overload. The runner was corrected to pass the camera; all six final traces passed.
+- The first fast-tier launch rejected a stale expected binary stamp. Clang/GCC binaries were rebuilt; the final 274-check run passed.
+- The broad route-parity diagnostic also failed on both the L79 baseline and unmodified L78 reference: FI had 3/8 base/page mismatches and 5,500 exact-query mismatches. This is pre-existing cross-route diagnostic behavior; the same-route point-bound inspection completed, and the final fast tier passed.
+
+No commit, push, or stash was made. The branch remains `assembler/world` at `ec20994`.