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Brandon ThomasandClaude Opus 5.5
0892148bab
- finish: sRGB encode through an interpolated 4096-entry table (< 2e-5 from the exact curve, tested), exp2 instead of powf(2, x). - guided / guided_fast: coefficient and output passes run row-parallel (were serial loops); Image::zip_map. - blur_bench reports process CPU time next to wall-clock (meaningful on a loaded machine). - RENDER_CACHE_VERSION 3 (exposure-after-filters and the table change pixels by <= 2 LSB). Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
43 lines
1.6 KiB
Rust
43 lines
1.6 KiB
Rust
//! Micro-benchmark for the blur/map primitives (min of N runs, wall-clock and process CPU time, so
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//! it stays meaningful on a loaded machine):
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//! `RAYON_NUM_THREADS=1 cargo run --release -p lightcraft-raster --example blur_bench`.
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use lightcraft_raster::{Plane, Rgb32f, blur::gaussian};
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use std::time::Instant;
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/// Process CPU time in ms (all threads). The only `unsafe` is this libc clock read, in a dev-only example.
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#[allow(unsafe_code)]
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fn cpu_ms() -> f64 {
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#[cfg(unix)]
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{
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let mut ts = libc::timespec { tv_sec: 0, tv_nsec: 0 };
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// SAFETY: `clock_gettime` only writes into the timespec we pass.
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unsafe { libc::clock_gettime(libc::CLOCK_PROCESS_CPUTIME_ID, &mut ts) };
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ts.tv_sec as f64 * 1e3 + ts.tv_nsec as f64 / 1e6
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}
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#[cfg(not(unix))]
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{
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0.0
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}
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}
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fn best(n: usize, mut f: impl FnMut()) -> String {
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let (mut wall, mut cpu) = (f64::MAX, f64::MAX);
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for _ in 0..n {
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let (t, c) = (Instant::now(), cpu_ms());
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f();
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cpu = cpu.min(cpu_ms() - c);
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wall = wall.min(t.elapsed().as_secs_f64() * 1e3);
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}
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format!("{wall:.1} ms wall, {cpu:.1} ms cpu")
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}
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fn main() {
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let (w, h) = (3000, 2400);
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let p = Plane::from_fn(w, h, |x, y| ((x * 7 + y * 13) % 255) as f32 / 255.0);
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let c = Rgb32f::from_fn(w, h, |x, y| [x as f32 / w as f32, y as f32 / h as f32, 0.5]);
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for sigma in [1.0f32, 4.0, 24.0] {
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println!("plane gaussian σ={sigma}: {}", best(9, || drop(gaussian(&p, sigma))));
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}
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println!("rgb gaussian σ=4: {}", best(9, || drop(gaussian(&c, 4.0))));
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}
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