SashegDev
874b6f20c2
Основа — Horizon (MIT). История апстрима не переносится: этот репозиторий ведёт свою.
53 lines
2.9 KiB
Markdown
53 lines
2.9 KiB
Markdown
# Generation scan gate benchmark
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`Streaming::update` now reuses an exhausted generation scan until its range,
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loaded membership, or generation state changes. Pending candidates keep the
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original per-frame bounded scheduling. Worker generation results and proto
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pruning invalidate the gate; light/mesh results do not. Public extra/forced
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ranges are compared exactly. `ChunkMap` tracks structural membership and map
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replacement, while value edits and existing-key replacement keep its token.
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The empty-extra/forced stationary gate is constant time; comparisons scale with
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those auxiliary ranges when present.
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Reproduce from the repository root:
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```sh
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CARGO_INCREMENTAL=0 CARGO_TARGET_DIR=/home/bob/Documents/horizon/target \
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cargo test -p horizon-client --lib --profile fast generation_scan_benchmark \
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-- --ignored --nocapture
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```
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The ignored test exercises the production candidate helper called by
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`Streaming::update`, compared against an independent copy of the original
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scan. It validates scheduled coordinates, job counts, and final membership
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and in-flight state. It uses a radius-32 decorated world: 5,041 scanned square
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positions, 3,409 finished resident keys and 552 outer-margin proto keys, capacity 12. Each sample runs 2,000
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frames, with one warmup sample and eight measured samples; values below are
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median nanoseconds per frame. The dynamic case removes the centre column every
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32 frames, schedules regeneration, and accepts a saved-load completion on the
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following frame.
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Measured on Linux x86-64, AMD Ryzen 5 5600X, Rust 1.99.0
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(`b940084d7`, 2026-09-28), optimized `fast` profile, 2026-10-14:
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| Scenario | Original | Gated | Speedup | Scans per 2,000 frames | Jobs original/gated |
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| --- | ---: | ---: | ---: | ---: | ---: |
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| Stationary fully resident | 15,441.3 ns | 10.1 ns | 1,528.99x | 2,000 / 0 | 0 / 0 |
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| Dynamic remove/load cycle | 14,794.3 ns | 1,004.8 ns | 14.72x | 2,000 / 126 | 63 / 63 |
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This is a generation scheduling microbenchmark, not a full-update, FPS, worker
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throughput, or startup benchmark. No prepared assets are needed: the fixture
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shares an empty real `Chunk` under different resident keys and uses unit
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protos because this path only reads membership. It excludes decoration execution, terrain generation, lighting,
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meshing, uploads, and other per-frame scans. The stationary speedup reflects
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replacing a completed scan with a small gate and should not be extrapolated to
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overall game performance. Timing and assertion overhead are included in both
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implementations. Memory cost is a u64 token per resident map plus a small gate
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snapshot and copies of extra/forced range metadata; no resident-key cache.
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Focused differential tests also cover movement, radius changes, extra and
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forced areas, removal/replacement at unchanged count, entire world reset,
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capacity pressure, staged generation membership, proto discard/retry, and
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light/content edits that should leave the gate reusable. `ChunkMap` tests cover
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structural tokens and value/light mutation separately.
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