VoxelForge/Standalone/Research/WorldAssemblerM3/Linux83/REPORT.md

Linux L83 — passage CPU and worker scaling

Base was L82 (f572108); the retained code is the exact L83 candidate. Logs and machine-readable results are under Saved/Linux/l83/. Every benchmark/headless process used CPUs 0–11; headless runs had a 6 GiB address-space cap and a 1,740 s timeout. This Intel i9-12900H host exposes six P cores / twelve P-core threads on that mask, so W16 is oversubscription. The Ryzen 5800X3D target was not measured directly.

L77 near-LOD census

Three L77 samples per world and version. Passage phase is the share of all near-LOD0–2 samples. Term shares use passage plus support-phase samples; these are PC/source-line attribution estimates, not subroutine wall-clock timers. unresolved is code without a resolved source-line term.

Term share	FI before → after	TN before → after
Carve distance evaluation	45.1% → 41.5%	43.5% → 39.2%
Support restoration / columns	16.6% → 14.9%	16.2% → 13.5%
Mouth shaping	4.3% → 4.2%	4.0% → 4.5%
Smooth joins / Catmull–Rom	0.7% → 0.8%	1.2% → 1.3%
Remaining relief	18.9% → 21.3%	19.7% → 23.7%
Other passage work	9.3% → 11.5%	10.2% → 11.5%
Unresolved passage body	5.1% → 5.8%	5.1% → 6.3%

Passage phase itself was FI 58.76% → 58.75%, TN 58.51% → 59.11% of near-LOD samples. Top exclusive symbols (% of passage-phase samples):

World/version	Top symbols
FI before	VisitNearestPassageSpatialNode 24.3%; ApplyResolvedStratePassageCarves 21.4%; VF_FieldCachedValueNoise 18.7%; PassagePotentialWithinNode 17.5%; carve lambda 10.2%
FI after	ApplyResolvedStratePassageCarves 21.3%; VF_FieldCachedValueNoise 20.8%; VisitNearestPassageSpatialNode 20.3%; PassagePotentialWithinNode 12.7%; carve lambda 11.8%
TN before	VisitNearestPassageSpatialNode 25.9%; ApplyResolvedStratePassageCarves 21.3%; VF_FieldCachedValueNoise 19.2%; PassagePotentialWithinNode 14.2%; carve lambda 12.3%
TN after	VF_FieldCachedValueNoise 22.8%; ApplyResolvedStratePassageCarves 21.8%; VisitNearestPassageSpatialNode 20.8%; carve lambda 13.1%; PassagePotentialWithinNode 10.5%

Exact cut and W8 readiness

Marked BVH nodes whose segment indices form a contiguous range, then skipped repeated lower_bound/membership work for those nodes. The nearest-node traversal now passes each already-computed child distance bound into recursion instead of calculating that bound again. A mask-only reachability trial was exact but showed mixed timing, so it was discarded.

L80 protocol: one warmup, then three interleaved L82/L83 pairs per stratum at W8. Cells show L82 → L83 median seconds; parentheses show the median of paired deltas.

Strate	LOD0–2 ready	Whole view
SW	1.088 → 1.058 (−0.021)	2.323 → 2.249 (−0.074)
FI	2.474 → 2.341 (−0.133)	3.756 → 3.591 (−0.165)
TN	2.386 → 2.431 (+0.058)	3.542 → 3.534 (−0.008)
VS	1.197 → 1.181 (−0.043)	2.233 → 2.171 (−0.109)

The cut is exact through LOD2: every near tile hash and the aggregate hash matched L82, with zero mismatches. Whole hashes (density / mesh / payload / topology):

Strate	L82 = L83 whole hash
SW (1,408 tiles)	4889b882f274930e / cafd187b455569f1 / 09e265430de5d9c8 / 498dc21d1fb4100e
FI (1,216 tiles)	3175bceb00bfc76c / d1dabfba70a95d8a / b23900f97cfbb2cf / 3967a02b7c1ae1c8
TN (1,344 tiles)	6b3e9f38209c1d8f / efa0d7b993928cbc / ede5b7bf3a771552 / 798dc428930aa2e2
VS (1,344 tiles)	e0c51b07a9a2016c / 99f2772314f721c5 / 922b324240786f79 / 6f8a836e0a17895c

Scaling

Final L83, L80 protocol: one warmup and three interleaved measured runs for each W4/W8/W12/W16 setting and stratum. Entries are median LOD0–2 / whole-view seconds; individual runs are in Saved/Linux/l83/scaling/summary.json.

Strate	W4	W8	W12	W16
SW	1.464 / 3.493	1.455 / 3.023	1.210 / 2.427	1.087 / 2.309
FI	3.592 / 5.341	2.478 / 3.791	2.328 / 3.566	2.342 / 3.608
TN	3.625 / 5.398	2.475 / 3.631	2.327 / 3.384	2.295 / 3.368
VS	1.540 / 3.160	1.205 / 2.242	1.274 / 2.254	1.158 / 2.218

FI/TN scale well from W4 to W8 and gain about 0.15 s near-ready at W12; W16 is essentially flat for FI and slightly better for TN. Whole-view results mostly flatten by W12. W16 does not consistently help across all strata. Three-run variance is material in some cells: SW W4 near-ready ranged 1.400–2.322 s (shape compile 0.413–1.027 s), and FI W12 near-ready ranged 2.286–2.634 s (shape 0.344–0.594 s).

Serial floor

At W16, the FI/TN timeline had shape_free_desired=0 and near_ring=0/27. Shape compilation ran asynchronously, but there were no tiles to generate during it, so it is on the critical path and did not overlap tile generation in these views. Shape-free tiles could overlap compilation in views that actually contain them.

An instrumented W16 pass estimates the infinite-worker floor as the maximum, over near tiles, of enqueue time plus that tile's measured service time: FI 1.014 s (last enqueue 0.430 s; maximum LOD0 service 0.587 s), TN 0.974 s (0.470 s; 0.506 s). This is an estimate from W16 service times, not a measured W∞ run. Shape compile in these passes was 0.347 s FI and 0.408 s TN; queue wait reached about 1.8 s, so the actual W16 runs still have substantial parallel backlog beyond that floor.

Verification and failed runs

• Fast tier passed in 299.8 s; source stamp 08af4e98c86a69477cc79e21463d8c93bcd11ebe0f077d7c11519031d9141fa9.
• No Unreal build was needed: no Unreal Source/ files changed.
• The first L77 parser attempt failed on a census regex unpack error; the parser was corrected and all six before/after FI/TN captures completed.
• The first fast-tier invocation stopped immediately because its output directory had no verification binary. After building that binary, the full tier passed.
• No timed-out benchmark or verification run. No commit, push, or stash.