VoxelForge/Standalone/Research/WorldAssemblerM3/Linux94/REPORT.md

Linux 94 — Unreal startup

Before and after

Medians are from L92's final serial-repair after-direct-json traces and L94's parallel-repair traces. Times start at BeginPlay, except export duration and core_compile_start → bReady. LOD0–2 means every currently desired key was settled before the scripted movement at 20 s.

Arrival	Measure	Before	After	Runs
SW	SerializeResolvedWorld	468.0 ms	115.2 ms	3 / 4
SW	Core compile → bReady	2.157 s	0.198 s	3 / 4
SW	bReady	2.738 s	0.421 s	3 / 4
SW	First admission	2.747 s	0.434 s	3 / 4
SW	LOD0–2 settled	5.198 s	2.813 s	3 / 3 of 4
SW	BeginPlay game-thread block	0.582 s	0.224 s	3 / 4
FI	SerializeResolvedWorld	465.6 ms	115.4 ms	3 / 3
FI	Core compile → bReady	0.184 s	0.180 s	3 / 3
FI	bReady	0.750 s	0.408 s	3 / 3
FI	First admission	0.762 s	0.422 s	3 / 3
FI	LOD0–2 settled	3.396 s	3.119 s	3 / 3
FI	BeginPlay game-thread block	0.570 s	0.229 s	3 / 3

Export, compile, bReady, admission and residency values are direct trace measurements. The SW route candidate log window fell from a 451 ms median to 96 ms (timestamps rounded to 1 ms); the enclosing export timer fell by 353 ms. The route window is a boundary measurement, not an internal function timer.

Changes and hashes

• Unreal now requests parallel sign-edge repair through its existing Unreal ParallelFor scheduler. The request remains capped at 10 workers on this 12-logical-core host; it creates no separate worker pool. Traces show compile launch queue delays of 0.04–0.18 ms. The first two seconds' sampled frame maximum was 28.7 ms in SW; FI had one 45.9 ms sample and two samples below 27.2 ms. The direct synchronous BeginPlay block is measured above.
• The SW fallback route planner checks its exact mouth-radius endpoint constraints before allocating route points or sampling terrain. It still visits 78,408 candidates, but skips heightfield work for the 58,480 placement rejects. Eligible candidates remain 35; the selected route remains center (32,80), direction 6, half-length 16, lift 128, with three sweep attempts.
• Headless sign-edge repair now defaults to parallel, with --serial-sign-edge-repair retained for A/B runs. The passage composer was not changed.
• Unreal world_assembly_hash=1ecc162755ab83ac, recipe_hash=52b010081ad4b550, and plan_hash=a06d76fd11d7a08e match L92 in every FI/SW run.
• Unreal SW sign_edge_distances fell from 1,942.2 ms to 36.5 ms median; ShapeStage fell from 2,156.3 ms to 198.1 ms. FI stayed effectively level: 8.8 → 9.5 ms and 183.5 → 179.8 ms.
• A serial/parallel Core hash A/B at the SW and FI spawn coordinates produced identical per-key tile hashes, full-detail hashes, whole-view hashes and per-LOD hashes. SW matched for 1,408 tiles (whole-view density/mesh/payload/topology: ba04e6da1010c52f / 93555a2b969b16a5 / 339eba0fad4f79a5 / c2edafbec2fa9305); FI matched for 1,216 tiles (3175bceb00bfc76c / d1dabfba70a95d8a / b23900f97cfbb2cf / 3967a02b7c1ae1c8). This focused headless A/B used the current owner-export manifest bcc0d0d33ea39435; the separate Unreal transient manifest is the 1ecc… hash above.
• In that headless A/B, SW sign_edge_distances was 1,753.9 ms serial and 86.4 ms parallel. The FI input had zero endpoint corrections in both modes.

Verification and failed runs

• Fast tier: PASS, 274 checks (269 PASS, 5 diagnostics), 297.1 s; source stamp 03a8fce1a9067edb8a83461a836292686d74abd8ea84b8014d8006296da8428d. Headless build and tier were pinned to CPUs 0–11 and capped at 6 GiB. Unreal Linux build succeeded with -NoUBA -MaxParallelActions=4, pinned to CPUs 0–11, without --as; it was not run during timing. The build emitted three existing RealtimeMesh deprecation warnings.
• SW repeat 3 exited Unreal successfully but missed three desired LOD0–2 tiles at the 20 s stationary boundary. They settled after movement began, at 25.36 s, so this run is excluded from the LOD median; repeat 4 completed the three-run residency sample.
• An auxiliary full CoreWorldTest without trace-only mode stopped before hashing: the host project's staged first-person Blueprint failed its MaxWalkSpeed pin preflight. The trace-only startup runs and the separate headless hash A/B completed.
• Logs and traces are under Saved/Linux/l94/; baseline traces are under Saved/Linux/l92/unreal-arrival/. RunL94UnrealArrival.py reproduces an individual Unreal trace run. No run exceeded 30 minutes. No commit, push or stash was made.

Source files

• Source/VoxelForge/Private/VoxelWorld.cpp
• Source/VoxelForge/Private/VoxelForgeCoreAdapter.cpp
• Standalone/Source/StreamBenchmarkHeadless.cpp