trace: Unreal timing traces run without hash capture (L71); verify baselines tracked

The L70 "2x SurfaceWorld GenerateTile in Unreal" was the instrument: the trace enabled
bCaptureVoxelForgeCoreHashesForValidation, which disables the native heightfield-band
shortcut and whole-tile skips (W1 same keys: 9.00 s hash-off vs 28.46 s hash-on). With
hashing off, Unreal and headless match at W8 within 1.2-2.5% (Core 14.42 s vs 14.26 s) on
identical tile keys. LOD0 p95 tail = real cost of non-empty passage tiles near the spawn mouth
(p50/p95 18.8/105 ms); most LOD0 tiles are empty.

verify.py reads its baselines from Standalone/Tools/verify/baselines/ instead of untracked
Saved/Linux. The 11 .vfmesh control meshes (~78 MB) are not committed yet (to be stored
compressed). Fast tier green.

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

Standalone/Research/WorldAssemblerM3/Linux71/RunEngineSurfaceTracesL71.py

@@ -0,0 +1,107 @@
+#!/usr/bin/env python3
+"""Measure production-path SurfaceWorld tile work without validation hashing."""
+from __future__ import annotations
+
+import argparse
+import json
+import subprocess
+import time
+from pathlib import Path
+
+
+ROOT = Path(__file__).resolve().parents[4]
+OUT = ROOT / "Saved/Linux/l71"
+ENGINE_OUT = OUT / "engine"
+HOST_PLUGIN_SAVED = Path("/home/jahni/VFHost/Plugins/VoxelForge/Saved/Linux/l71")
+PROJECT = Path("/home/jahni/VFHost/VFHost.uproject")
+EDITOR = Path("/home/jahni/UnrealEngine/Engine/Binaries/Linux/UnrealEditor-Cmd")
+SPAWN_M = (8.0, 16.0, -372.2626953125)
+
+
+def run(trial: int) -> dict:
+    label = f"strate0-trial{trial}"
+    traces = ENGINE_OUT / "traces"
+    trace = traces / f"{label}.trace.jsonl"
+    abslog = traces / f"{label}.log"
+    stdout = traces / f"{label}.stdout.log"
+    # VoxelForgeExplore restricts exported content to the host plugin's Saved tree.
+    output = HOST_PLUGIN_SAVED / "output" / label
+    userdir = ENGINE_OUT / "user" / label
+    zendata = ENGINE_OUT / "zen" / label
+    ddc = ENGINE_OUT / "DDC"
+    for directory in (traces, 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(PROJECT), "-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=0", "-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=0",
+        "-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", "-coreworldstreamtrace=1", "-voxel.TestMove=0",
+        "-voxel.TestMoveSpeedCmPerSecond=0", f"-voxel.StartupTraceSpawnCm={spawn_cm}",
+        f"-voxel.StartupTraceFile={trace}", "-voxel.StartupTraceUntilEndPlay=1",
+        "-voxel.StartupTraceMaxTiles=16384", "-voxel.CollisionGate=0", f"-abslog={abslog}",
+    ]
+    started = time.monotonic()
+    with stdout.open("w", encoding="utf-8") as stream:
+        # UE itself is CPU-pinned and time-bounded. Linux does not enforce --rss.
+        result = subprocess.run(
+            ["taskset", "-c", "0-11", "timeout", "1740s", *command],
+            cwd=ROOT, stdout=stream, stderr=subprocess.STDOUT, check=False, timeout=1740,
+        )
+    elapsed = time.monotonic() - started
+    events = set()
+    if trace.is_file():
+        for line in trace.read_text(encoding="utf-8", errors="replace").splitlines():
+            try:
+                events.add(json.loads(line).get("type", ""))
+            except json.JSONDecodeError:
+                continue
+    row = {
+        "label": label,
+        "trial": trial,
+        "spawn_m": SPAWN_M,
+        "elapsed_s": round(elapsed, 3),
+        "exit_code": result.returncode,
+        "trace": str(trace),
+        "stdout": str(stdout),
+        "events": sorted(events),
+        "has_walkable_gate": "walkable_gate" in events,
+        "has_lod0_ring": "lod0_ring_ready" in events,
+        "has_initial_set": "stream_trace_milestone" in events,
+        "has_summary": "summary" in events,
+    }
+    print(f"[L71EngineTrace] {json.dumps(row, sort_keys=True)}", flush=True)
+    return row
+
+
+def main() -> int:
+    parser = argparse.ArgumentParser(description=__doc__)
+    parser.add_argument("--trials", type=int, default=3, choices=range(1, 4))
+    args = parser.parse_args()
+    if not EDITOR.is_file() or not PROJECT.is_file():
+        raise SystemExit(f"missing UnrealEditor-Cmd or host project: {EDITOR} {PROJECT}")
+    rows = [run(trial) for trial in range(1, args.trials + 1)]
+    summary = ENGINE_OUT / "surface-trace-summary.json"
+    summary.write_text(json.dumps(rows, indent=2) + "\n", encoding="utf-8")
+    complete = all(row["exit_code"] == 0 and row["has_walkable_gate"]
+                   and row["has_lod0_ring"] and row["has_initial_set"] and row["has_summary"]
+                   for row in rows)
+    print(f"[L71EngineTraceSet] trials={len(rows)} status={'PASS' if complete else 'INCOMPLETE'} "
+          f"summary={summary}", flush=True)
+    return 0 if complete else 2
+
+
+if __name__ == "__main__":
+    raise SystemExit(main())