mirror of
https://github.com/storytold/photocraft.git
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AyanandBrandon Thomas
acce8e0e99
* Rasterize Extrude blocks and scatter Wind streaks once * Prepare Spin Blur rotations and fixed-channel sampling * Share Lens Correction interpolation across color and alpha * Make wide prepress traps independent of radius * Add full-operation timing for five imaging algorithms * Record 24 full-operation benchmarks and exact-output checks --------- Co-authored-by: Brandon Thomas <[email protected]>
153 lines
8.3 KiB
Markdown
153 lines
8.3 KiB
Markdown
# Five imaging algorithms: measured CPU performance
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Measured on 2026-10-10. These changes remove repeated work from Extrude Blocks,
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Wind/Blast, Spin Blur, Lens Correction and prepress Trap. They preserve the existing
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output and parameter behavior. Measurements compare the full CPU operation against
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`7722172585a01cbdb93c06f0f5ff2634fcb17999`, not just the inner kernel.
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## What changed
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- **Extrude Blocks:** visit each cell once, calculate its color and height once, then
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rasterize its swept bounds. Keep the original candidate-range checks, intersection
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tests and cell tie order. The default 30 px blocks benefit too, not only dense blocks.
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- **Wind/Blast:** scatter each actual source streak once. Reuse source luminance and
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hash work, retain the nearest-source tie rule, then blend once per output pixel.
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- **Spin Blur:** prepare all 2..64 sample-count rotation tables once per pin. Fixed
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channel samplers keep bilinear accumulators in registers without changing tap or
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premultiplied-alpha arithmetic order.
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- **Lens Correction:** share Catmull-Rom coordinates and weights across channels
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sampling the same point, using fixed channel accumulators. RGB chromatic-aberration
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offsets still use independent samples.
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- **Trap:** replace wide-window ink scans with separable prefix/suffix block maxima,
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independent of radius. Transpose the intermediate output for contiguous column
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writes. Widths 1 and 2 retain the original path.
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## Method
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AWS m7i.4xlarge, 16 vCPUs, Intel Xeon Platinum 8488C, 61 GiB RAM, Ubuntu 24.04.5.
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Rust `1.99.0 (b940084d7 2026-09-28)`, release profile, `RAYON_NUM_THREADS=16`.
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Builds used independent target directories. No build or test ran during timing.
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The final rebase adds upstream canvas and automation changes; the timed algorithm
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source, fixture, dependencies and Cargo configuration are unchanged. The raw results
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record both the measured revision and its equivalent rebased revision.
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The identical committed `bench_algorithms` example runs at both revisions. It creates
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native RGB or CMYK tiles at 8-bit, 16-bit or 32-bit float depth, with deterministic
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65536-level busy texture, variable alpha and roughly 20% zero-alpha pixels. Bounds begin at
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(-17, -29). A 128 x 128 operation warms each process before timing.
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Each case has three independent before/after pairs, alternating process order:
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before/after, after/before, before/after. The table reports the median of each set
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of three, with speedup computed from unrounded medians. Fixture construction,
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warmup, output serialization and result destruction are outside the timer.
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For filters, the timer includes `apply_in`, tile reads, processing, writeback and
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pruning. Lens times the full `lens::correct` call. Trap includes surface reads,
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ink dilation, clone, writeback and pruning. Document flattening, undo bookkeeping
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and UI rendering are outside these CPU measurements.
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Every pair serializes every output sample as its normalized f32 bits in tile order.
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All 72 before/after SHA-256 comparisons match exactly, including alpha. The
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[raw results](five-algorithm-performance.json) contain all times, medians and hashes.
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Extrude uses random-depth Blocks, seed 17, size/depth 30/30 px, or 8/128 px for
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`extrude-dense`; solid-front, level-based and incomplete-cell masking are off.
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Wind/Blast use seed 17; `blast-right` changes direction. `spin` uses one full-frame
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elliptical pin, 30 degree blur and 17 degree orientation; `spin-default` uses the
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unchanged default pin. Lens uses distortion 12, rotation 2.5 degrees and vignette 20;
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`lens-ca` also enables red/cyan 12 and blue/yellow -8. Trap widths are 10, 50
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(`trap-wide`) and 1 (`trap-default`) pixels.
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## Full-operation results
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| Case | Dimensions | Mode/depth | Before (s) | After (s) | Speedup |
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|---|---|---|---:|---:|---:|
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| `extrude` | 6000 x 4000 | RGB/u8 | 2.0641 | 0.3296 | 6.26x |
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| `extrude-dense` | 6000 x 4000 | RGB/u8 | 160.3010 | 0.3866 | 414.69x |
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| `extrude` | 7200 x 5000 | RGB/u8 | 3.1539 | 0.4954 | 6.37x |
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| `extrude` | 6000 x 4000 | RGB/u16 | 2.1515 | 0.4004 | 5.37x |
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| `extrude` | 6000 x 4000 | RGB/f32 | 2.2541 | 0.4774 | 4.72x |
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| `blast` | 6000 x 4000 | RGB/u8 | 1.4413 | 0.4114 | 3.50x |
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| `blast` | 7200 x 5000 | RGB/u8 | 2.1646 | 0.6327 | 3.42x |
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| `blast` | 6000 x 4000 | CMYK/u8 | 6.2310 | 0.7092 | 8.79x |
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| `blast-right` | 6000 x 4000 | RGB/u16 | 1.5043 | 0.4821 | 3.12x |
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| `wind` | 6000 x 4000 | RGB/f32 | 0.7678 | 0.4866 | 1.58x |
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| `wind` | 6000 x 4000 | CMYK/u8 | 2.5829 | 0.6568 | 3.93x |
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| `spin` | 6000 x 4000 | RGB/u8 | 6.3307 | 3.9093 | 1.62x |
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| `spin-default` | 6000 x 4000 | RGB/u8 | 1.5961 | 1.1203 | 1.42x |
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| `spin` | 7200 x 5000 | RGB/u8 | 9.4388 | 5.8694 | 1.61x |
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| `spin` | 6000 x 4000 | RGB/u16 | 6.3066 | 3.9617 | 1.59x |
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| `spin` | 6000 x 4000 | RGB/f32 | 6.3749 | 4.0619 | 1.57x |
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| `lens` | 6000 x 4000 | RGB/u8 | 0.6208 | 0.4448 | 1.40x |
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| `lens` | 6000 x 4000 | CMYK/u16 | 0.8080 | 0.5649 | 1.43x |
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| `lens` | 6000 x 4000 | RGB/f32 | 0.6847 | 0.5103 | 1.34x |
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| `lens-ca` | 6000 x 4000 | RGB/u8 | 0.6214 | 0.6312 | 0.98x |
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| `trap` | 6000 x 4000 | CMYK/u8 | 0.9710 | 0.8082 | 1.20x |
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| `trap-wide` | 7200 x 5000 | CMYK/u16 | 4.6265 | 1.3331 | 3.47x |
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| `trap` | 6000 x 4000 | CMYK/f32 | 1.1924 | 1.0273 | 1.16x |
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| `trap-default` | 6000 x 4000 | CMYK/u8 | 0.6363 | 0.6506 | 0.98x |
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## Correctness and bounded work
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407 algorithm tests passed, with 14 existing ignored tests. New direct-reference
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comparisons cover all eight color models, alpha on/off, all three depths, edge
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modes, unusual tile sizes and soft selections where applicable. They also exercise
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ties, partial cells, extreme coordinates, nonfinite samples and fallback paths.
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Spin rotation tables match the original trigonometric results bit for bit.
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Trap tests include clipped windows, paper preservation, extra channels and signed zero.
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Extrude caps its additional winner plane at 4,194,304 pixels (16 MiB), cell visits
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at 262,144 and coordinates at +/-2^22; normal tiled execution fits these bounds.
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Wind caps winner scratch at 1,048,576 entries per row (8 MiB). Spin tables are
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under 2 MiB for up to 120 pins. These scratch allocations are fallible and use the
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original direct implementation if preparation fails or bounds are exceeded.
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Extrude Pyramids and Wind Stagger keep their original implementations. Trap's new
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per-line suffix buffer is fallible, with a direct fallback; it adds no full-image
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plane beyond the existing dilation workspace. Lines containing negative zero use
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the original scan to retain float bit patterns.
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`cargo fmt --all -- --check`, algorithm clippy with all targets and denied warnings,
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`cargo xtask layers`, full `cargo xtask wasm`, `cargo xtask perf --quick`, and
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scorecard generation/check passed. The quick performance run used llvmpipe and
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still reports existing over-budget UI scenarios. These operation measurements do
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not change those budget claims or establish Photoshop pixel parity.
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## Reproduce
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From the PR checkout, create a base worktree and copy only the benchmark fixture:
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```sh
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base=7722172585a01cbdb93c06f0f5ff2634fcb17999
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git worktree add --detach ../photocraft-five-base "$base"
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cp crates/algo/examples/bench_algorithms.rs ../photocraft-five-base/crates/algo/examples/
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CARGO_TARGET_DIR="$PWD/target/five-after" cargo build --release -p photocraft-algo --example bench_algorithms
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(cd ../photocraft-five-base && CARGO_TARGET_DIR="$PWD/target/five-before" cargo build --release -p photocraft-algo --example bench_algorithms)
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before="$PWD/../photocraft-five-base/target/five-before/release/examples/bench_algorithms"
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after="$PWD/target/five-after/release/examples/bench_algorithms"
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export RAYON_NUM_THREADS=16
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# Each invocation prints its full-operation time. Keep the machine otherwise idle.
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# Use the case names, dimensions, depth and mode from the table.
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case=extrude-dense
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w=6000
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h=4000
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depth=u8
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mode=rgb
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for pair in 1 2 3; do
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if [ "$pair" = 2 ]; then
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"$after" "$case" "$w" "$h" "$depth" 1 after.bin "$mode"
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"$before" "$case" "$w" "$h" "$depth" 1 before.bin "$mode"
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else
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"$before" "$case" "$w" "$h" "$depth" 1 before.bin "$mode"
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"$after" "$case" "$w" "$h" "$depth" 1 after.bin "$mode"
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fi
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cmp before.bin after.bin || exit 1
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sha256sum before.bin after.bin
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done
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```
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Take the median of the three times for each binary. Output files can reach 720 MB
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per side for 36 MP CMYK+alpha; reuse the two filenames between cases. Hardware,
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worker count and image content affect the times, so preserve the fixture when
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comparing revisions.
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