Fr0zkaandClaude Opus 5.5
8d62ba57ed
FI/TN LOD0-2 W12 worker CPU 13.9/12.2 s: passages 40/35%, far-shell refinement (HasDownwardHit/ HasUpwardHit ~1.7-1.9 s) in 'other' 27/30%, support 14/13%, dispatch 8%, base field 6%, bands 6%. Workers 28%/24% idle during LOD0-1. Near-ready W12: SW 0.77, FI 1.51, TN 1.38, VS 0.96 s. Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com> Claude-Session: https://claude.ai/code/session_016dhxM43dnWvUu2B5Ph1iG1
126 lines
6.7 KiB
Markdown
126 lines
6.7 KiB
Markdown
# Linux103 — current near-ready cost account
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Source stamp: `c5f49a45f51856b857a1ee8877b7d777208e67daf64281caefc7ef84e8006410`.
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L77 cost rows are medians of three W12 profiles per stratum. Phase CPU is estimated by
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sample share, calibrated to direct tile-worker CPU. Timer weights include `1 + si_overrun`.
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## W12 cost
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| LOD0–2 worker cost | FI | TN | Measurement |
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|---|---:|---:|---|
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| Direct tile-worker CPU | 13.919 s | 12.155 s | Direct worker timers |
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| Passage phase | 5.538 s (39.8%) | 4.209 s (34.6%) | L77 sample allocation |
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| Other phase | 3.749 s (26.9%) | 3.681 s (30.4%) | L77 sample allocation; mostly far-shell refinement |
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| Support | 1.864 s (13.7%) | 1.623 s (13.0%) | L77 sample allocation |
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| Dispatch lookup | 1.107 s (8.0%) | 1.043 s (8.6%) | L77 sample allocation |
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| Base field | 0.831 s (6.1%) | 0.808 s (6.5%) | L77 sample allocation |
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| Composition bands | 0.773 s (5.7%) | 0.781 s (6.3%) | L77 sample allocation |
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| Graph, caps, edits | 0.084 s | 0.053 s | L77 sample allocation |
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Phase rows partition the worker total. Direct stage timers overlap that account: MC total/grid
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fill was `9.838 / 9.263 s` FI and `7.827 / 7.340 s` TN; skirt mesh was `0.656 / 0.661 s`.
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Grid-fill sample estimates closed against direct `mc_grid_ms` at 100.0% FI and 99.8% TN.
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Whole near-worker sample closure was 99.2% FI and 99.1% TN.
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Passage share is 39.8% FI / 34.6% TN. L99's earlier W8 census reported 34.78% / 28.81%;
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that comparison crosses source stamps and worker counts. Current near exact-fallback calls
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(901,055 / 607,012) make off-grid exact work a plausible contributor, but its causal share was
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not isolated.
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Top route × phase allocations (direct-worker-equivalent seconds):
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| Stratum | Largest route × phase costs |
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|---|---|
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| FI | packed-scalar passages 4.533; analytic-scalar passages 0.936; packed support 1.651; packed bands 0.641; dispatch 1.095; unknown/other 3.745 |
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| TN | packed-scalar passages 3.119; analytic-scalar passages 1.089; packed support 1.394; packed bands 0.671; dispatch 1.035; unknown/other 3.673 |
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Passage sweep work: FI used 3,371,576 base and 347,335 detail samples (90.7% / 9.3%);
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TN used 3,145,983 and 332,547 (90.4% / 9.6%). Symbolized samples attribute about
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`0.247 / 0.143 s` FI and `0.261 / 0.169 s` TN to base/detail preparation, `1.010 / 0.739 s`
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to sweep lookups, and `0.822 / 0.585 s` to exact-route visits plus miss-bound tests. Those
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subcosts are sampled estimates, not separate direct timers.
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Near LOD0–2 sweep disposition was FI `13,903,288 misses = 901,055 exact fallbacks + 13,002,233
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skips`; TN `9,086,664 = 607,012 + 8,479,652`. The exact-fallback totals include 255,529 FI and
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250,311 TN skirt queries. Near far-shell stratum refinement made 410,980 FI and 447,978 TN
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off-grid queries. Symbolized `HasDownwardHit` / `HasUpwardHit` samples attribute about 1.73 s
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FI and 1.85 s TN to those hit checks.
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Whole-view off-grid caller counts, per run:
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| Caller | FI | TN |
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|---|---:|---:|
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| MC midpoint unique points | 29,101 | 29,864 |
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| Skirt surface / extruded / clipped vertices | 21,380 / 192,868 / 26,365 | 21,082 / 191,186 / 22,643 |
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| Skirt refinement face / coarse centroid | 188,382 / 210,056 | 184,353 / 209,077 |
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| Far-shell surface / projection-normal queries | 539,321 / 192 | 539,321 / 192 |
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| Far-shell stratum refinement | 1,131,895 | 1,145,781 |
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Across all four strata, all-view sweep misses totaled 63,036,259: 1,908,562 exact fallbacks and
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61,127,697 skips. Skip reasons were feature bound 59,646,691; tile free 147,272; vertical bound
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160,272; negative reach 1,158,700; positive reach 14,762. Per-caller miss totals equal exact
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fallbacks plus skips; unaccounted misses are zero. All 12 W12 profiles had zero lost samples,
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and their parsed sample counts and expanded-tick sums matched.
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## Critical path and readiness
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In the W12 timeline traces, FI LOD0–1 settled at 1.605 s; TN at 1.218 s. The far-parent build
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then took 171 ms FI / 114 ms TN. The LOD2 batch started as the far parent completed and drained
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in 56 / 79 ms. Shape compile was 311 / 200 ms in the traces. Worker-pool busy time was 70.7%
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FI / 75.0% TN, with 28.3% / 24.3% explicitly idle. The long interval is LOD0–1 tile work;
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the LOD2 tail is short.
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L80 protocol medians, `near LOD0–2 / whole view` seconds, three interleaved runs per cell:
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| Stratum | W8 | W12 |
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|---|---:|---:|
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| SW | 0.764 / 1.914 | 0.772 / 1.786 |
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| FI | 1.612 / 2.593 | 1.508 / 2.404 |
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| TN | 1.510 / 2.432 | 1.377 / 2.199 |
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| VS | 1.107 / 2.061 | 0.958 / 1.822 |
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The W12 whole-view pipeline reported shape / far-shape times of 0.199 / 0.114 s FI and
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0.215 / 0.114 s TN.
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## Next lever
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No single value-preserving code change was clear from the timers, so L103 ships the following
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ranked candidates. Savings are inferred CPU scenarios; elapsed-time gains and hash preservation
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need a changed build to measure.
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1. Reduce passage sweep/carve work. It is 5.54 s FI / 4.21 s TN; a 10% reduction would save
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about 0.55 / 0.42 worker CPU seconds.
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2. Reduce far-shell hit checks. The symbolized estimate is 1.73 / 1.85 s; a 25% reduction would
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save about 0.43 / 0.46 worker CPU seconds. The million-plus whole-view refinement queries make
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this the best bounded target to investigate.
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3. Reduce support traversal. It is 1.86 / 1.62 s; a 25% reduction would save about
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0.47 / 0.41 worker CPU seconds.
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## Hashes and checks
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All 24 whole-view runs matched across Clang/GCC W1/W8/W12. The 20 peer comparisons had identical
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tile counts and zero density, mesh, payload, or topology mismatches. All 24 hashes also equal
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the corresponding L101 runs.
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| Stratum | Tiles | Clang W1 whole hash: density / mesh / payload / topology |
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|---|---:|---|
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| SW | 2,850 | `8723d8c61348bf31 / fe1c3e410373a343 / bf111bbc45e2f017 / c9c562b100b51f7f` |
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| FI | 2,249 | `6bb633f756e2b8be / fe930e83b0dc6bf3 / 5298602285b6892c / e306f87ae432a4fc` |
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| TN | 2,233 | `612b2d11fc6bd946 / c026a40c6127d649 / 0f9036914e28fe46 / 94b36e5f73694eff` |
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| VS | 2,329 | `99c93f4c7155ffb3 / 488d421c6438f529 / 249b5afc12be4540 / 9c5e22f6dc1e44b8` |
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Fast tier: **PASS**, 274 checks (269 pass, five retained diagnostics), 274.4 s. No production
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`Source/` files changed, so no Unreal build or arrival trace was required.
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## Failed or excluded runs
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- The first fast-tier launch exited before running checks because its temporary binary symlink
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was wrong. The corrected run passed.
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- The first readiness launch had no output directory and started no headless process; all 32
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subsequent warmup/measured runs completed.
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- The W8 census and an earlier policy-3 census are retained separately and excluded from the
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final W12 account. All final W12 census, timeline, readiness, and hash headless runs passed.
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Headless runs used `taskset -c 0-11 prlimit --as=6442450944` and a 1,740-second timeout.
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Artifacts are under `Saved/Linux/l103/`.
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