streaming: split dense passage-junction grid fills; heavy-first order + far-parent deferral in Unreal (L85)

Tiles with passage-overlap score >= 9 split grid fill over up to 4 helper lanes (disjoint rows,
same per-sample order, join before MC) when workers are idle. FI junction tile fill 173 -> 99 ms;
estimated serial floor ~0.55-0.60 s. Readiness essentially unchanged (FI/TN LOD0-2 ~2.15 s @W12):
the limit is now aggregate work, not single tiles.
Unreal: LOD0-2 ordered by passage overlap before travel/distance (L80 modes kept); far parents
built after LOD0-1, LOD2 gated on them; helper budget via ParallelFor. Unreal null-RHI FI
arrival: LOD0-2 resident at 3.65 s.
All tile hashes identical to L84 (four whole views). 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/Linux85/RunL85UnrealFITrace.py

@@ -0,0 +1,113 @@
+#!/usr/bin/env python3
+"""One Unreal null-RHI streaming trace starting in the FI stratum."""
+from __future__ import annotations
+
+import json
+import re
+import subprocess
+import time
+from pathlib import Path
+
+ROOT = Path(__file__).resolve().parents[4]
+HOST = Path("/home/jahni/VFHost")
+EDITOR = Path("/home/jahni/UnrealEngine/Engine/Binaries/Linux/UnrealEditor-Cmd")
+OUT = ROOT / "Saved/Linux/l85/unreal-fi"
+HOST_PLUGIN_SAVED = HOST / "Plugins/VoxelForge/Saved/Linux/l85"
+HOST_SAVED = HOST / "Saved/Linux/l85"
+SPAWN_M = (25.8369140625, 3.19921875, -737.0)
+SAMPLE_SECONDS = 0.25
+MOVE_START_S = 6.0
+MOVE_DURATION_S = 12.0
+DWELL_S = 5.0
+EXIT_S = MOVE_START_S + MOVE_DURATION_S + DWELL_S
+
+
+def main() -> int:
+    if not EDITOR.is_file():
+        raise SystemExit(f"missing Unreal commandlet executable: {EDITOR}")
+    label = "fi-arrival-l85"
+    trace = OUT / f"{label}.trace.jsonl"
+    abslog = OUT / f"{label}.log"
+    stdout = OUT / f"{label}.stdout.log"
+    output = HOST_PLUGIN_SAVED / "output" / label
+    userdir = HOST_SAVED / "user" / label
+    zendata = HOST_SAVED / "zen" / label
+    ddc = HOST_SAVED / "DDC"
+    for directory in (OUT, output, userdir, zendata, ddc):
+        directory.mkdir(parents=True, exist_ok=True)
+    spawn_cm = ",".join(f"{value * 100.0:.3f}" for value in SPAWN_M)
+    command = [
+        str(EDITOR), str(HOST / "VFHost.uproject"), "-nullrhi", "-unattended",
+        "-nop4", "-nosplash", "-NoSound", "-corelimit=12", "-NoZenAutoLaunch",
+        "-notraceserver", "-nocrashreports", "-DisablePlugins=AndroidFileServer",
+        "-ddc=NoZenLocalFallback", f"-userdir={userdir}", f"-ZenDataPath={zendata}",
+        f"-LocalDataCachePath={ddc}", "-run=VoxelForgeExplore", "-seed=0",
+        "-archetype=TunnelNetwork", "-slot=1", "-modes=export", "-gameconfig=1",
+        "-coreworldtest=1", "-ownerfourstrateplan=1", "-corevoxelsizecm=25",
+        "-coreislandtest=0", "-corefallbacktest=0", "-coreofftest=0", "-coreplantest=0",
+        "-settingsref=/Game/VoxelForge/DA_Settings.DA_Settings", "-corehybridmesher=0",
+        f"-out={output}", "-voxel.StreamingCoarseFirst=1",
+        "-voxel.StreamingDynamicNearReserve=1", "-voxel.StreamingLegacyPendingResultCap=0",
+        "-voxel.CoreRegionConcurrentAdmission=1", "-voxel.StreamingResultBacklogCap=256",
+        "-voxel.StreamingReadyQueueDepth=8", "-voxel.StreamingBackgroundWorkerCap=1",
+        "-voxel.CoreColumnCacheDirectMapped=0", "-voxel.CoreMCGradientMemoization=1",
+        "-voxel.StreamingCollisionLookahead=1", "-voxel.TestMove=1",
+        "-voxel.TestMoveSpeedCmPerSecond=140.0",
+        f"-voxel.TestMoveStartSeconds={MOVE_START_S:.1f}",
+        f"-voxel.TestMoveDurationSeconds={MOVE_DURATION_S:.1f}",
+        f"-voxel.TestExitSeconds={EXIT_S:.1f}", "-voxel.TestMoveDirection=1,0,0",
+        "-voxel.StreamingSchedulerPolicy=3", "-voxel.TestExitOnSteady=0",
+        "-coreworldstreamtrace=1", f"-voxel.StartupTraceSpawnCm={spawn_cm}",
+        "-voxel.StartupTraceUntilEndPlay=1", "-voxel.StartupTraceThroughCrossing=1",
+        "-voxel.StartupTraceMaxTiles=16384", f"-voxel.StartupTraceFile={trace}",
+        f"-abslog={abslog}",
+    ]
+    wrapped = ["taskset", "-c", "0-11", "timeout", "1740s", *command]
+    started = time.monotonic()
+    OUT.mkdir(parents=True, exist_ok=True)
+    with stdout.open("w", encoding="utf-8") as stream:
+        result = subprocess.run(wrapped, cwd=ROOT, stdout=stream,
+                                stderr=subprocess.STDOUT, check=False, timeout=1740)
+    events = []
+    if trace.is_file():
+        for line in trace.read_text(encoding="utf-8", errors="replace").splitlines():
+            if line.startswith("{"):
+                try:
+                    events.append(json.loads(line))
+                except json.JSONDecodeError:
+                    pass
+    samples = [event for event in events if event.get("type") == "streaming_sample"]
+    arrival = [event for event in samples if float(event.get("t_s", 0.0)) < MOVE_START_S]
+    full = []
+    for event in arrival:
+        desired = sum(event.get("desired_by_lod", [0] * 9)[:3])
+        resident = sum(event.get("resident_by_lod", [0] * 9)[:3])
+        if desired and resident >= desired:
+            full.append(event)
+            break
+    row = {
+        "label": label, "exit_code": result.returncode,
+        "wall_s": round(time.monotonic() - started, 3),
+        "sample_count": len(samples), "arrival_sample_count": len(arrival),
+        "first_lod02_full_ready_s": full[0]["t_s"] if full else None,
+        "first_lod02_full_desired": (sum(full[0].get("desired_by_lod", [0] * 9)[:3])
+                                     if full else None),
+        "first_lod02_full_resident": (sum(full[0].get("resident_by_lod", [0] * 9)[:3])
+                                      if full else None),
+        "trace": str(trace.relative_to(ROOT)), "abslog": str(abslog.relative_to(ROOT)),
+        "stdout": str(stdout.relative_to(ROOT)),
+    }
+    failure = re.search(r"\[VoxelForgeCoreWorldTest\] failed: ([^\r\n]+)",
+                        stdout.read_text(encoding="utf-8", errors="replace"))
+    if failure:
+        row["world_test_failure"] = failure.group(1)
+    (OUT / "summary.json").write_text(json.dumps(row, indent=2) + "\n",
+                                       encoding="utf-8")
+    print("[L85UnrealFITrace] " + json.dumps(row, sort_keys=True), flush=True)
+    if result.returncode or len(samples) < 40:
+        raise SystemExit("Unreal FI trace did not complete successfully")
+    return 0
+
+
+if __name__ == "__main__":
+    raise SystemExit(main())