cubecl_runtime/tune/
util.rs

1use core::sync::atomic::{AtomicI32, Ordering};
2
3/// Autotune levels:
4///
5/// '0' => Minimal autotune: scaled anchor of '1.25'.
6/// '1' => Medium autotune: normal anchor.
7/// '2' => More autotune: scaled anchor of '0.75'.
8/// '3' => Autotune everything without anchor.
9static AUTOTUNE_LEVEL: AtomicI32 = AtomicI32::new(-1);
10static DEFAULT_LEVEL: u32 = 1;
11
12/// Anchor a number to a power of the provided base.
13///
14/// Useful when creating autotune keys.
15pub fn anchor(x: usize, max: Option<usize>, min: Option<usize>, base: Option<usize>) -> usize {
16    let autotune_level = load_autotune_level();
17    let factor = match autotune_level {
18        3 => return x, // Autotune everything, there is no anchor.
19        2 => 0.75,
20        1 => 1.0,
21        0 => 1.25,
22        _ => panic!("Invalid autotune level {autotune_level:?}"),
23    };
24
25    let base = base.unwrap_or(2) as f64 * factor;
26    let base = f64::max(base, 1.1); // Minimum base.
27    let exp = (x as f64).log(base).ceil();
28    let power = base.powf(exp).ceil() as usize;
29
30    let result = if let Some(max) = max {
31        core::cmp::min(power, max)
32    } else {
33        power
34    };
35
36    if let Some(min) = min {
37        core::cmp::max(result, min)
38    } else {
39        result
40    }
41}
42
43fn load_autotune_level() -> u32 {
44    let autotune_level = AUTOTUNE_LEVEL.load(Ordering::Relaxed);
45    if autotune_level == -1 {
46        #[cfg(feature = "std")]
47        {
48            let level: u32 = std::env::var("CUBECL_AUTOTUNE_LEVEL")
49                .map(|value| {
50                    value
51                        .parse()
52                        .expect("'CUBECL_AUTOTUNE_LEVEL' should be an integer.")
53                })
54                .unwrap_or(DEFAULT_LEVEL);
55            AUTOTUNE_LEVEL.store(level as i32, Ordering::Relaxed);
56            level
57        }
58        #[cfg(not(feature = "std"))]
59        DEFAULT_LEVEL
60    } else {
61        autotune_level as u32
62    }
63}
cubecl_runtime/tune/util.rs

cubecl_runtime/tune/
util.rs
