fix(divan): use busy sleep in time scale examples

GuillaumeLagrange · GuillaumeLagrange · commit e5436a54a6af · 2025-11-07T14:11:48.000+01:00
For these times, using `thread::sleep` makes no sense as, at least on
linux, the scheduler's timer resolution is orders of magnitude larger
than nanoseconds.
diff --git a/crates/divan_compat/examples/benches/time_scale.rs b/crates/divan_compat/examples/benches/time_scale.rs
@@ -2,24 +2,29 @@ fn main() {
     divan::main();
 }
 
+fn busy_sleep(duration: std::time::Duration) {
+    let start = std::time::Instant::now();
+    while start.elapsed() < duration {}
+}
+
 #[divan::bench]
 fn sleep_1ns() {
-    std::thread::sleep(std::time::Duration::from_nanos(1));
+    busy_sleep(std::time::Duration::from_nanos(1));
 }
 
 #[divan::bench]
 fn sleep_100ns() {
-    std::thread::sleep(std::time::Duration::from_nanos(100));
+    busy_sleep(std::time::Duration::from_nanos(100));
 }
 
 #[divan::bench]
 fn sleep_1us() {
-    std::thread::sleep(std::time::Duration::from_micros(1));
+    busy_sleep(std::time::Duration::from_micros(1));
 }
 
 #[divan::bench]
 fn sleep_100us() {
-    std::thread::sleep(std::time::Duration::from_micros(100));
+    busy_sleep(std::time::Duration::from_micros(100));
 }
 
 #[divan::bench]

Original file line number	Diff line number	Diff line change
`@@ -2,24 +2,29 @@ fn main() {`
`2`	`2`	`divan::main();`
`3`	`3`	`}`
`4`	`4`
	`5`	`+fn busy_sleep(duration: std::time::Duration) {`
	`6`	`+ let start = std::time::Instant::now();`
	`7`	`+ while start.elapsed() < duration {}`
	`8`	`+}`
	`9`	`+`
`5`	`10`	`#[divan::bench]`
`6`	`11`	`fn sleep_1ns() {`
`7`		`- std::thread::sleep(std::time::Duration::from_nanos(1));`
	`12`	`+ busy_sleep(std::time::Duration::from_nanos(1));`
`8`	`13`	`}`
`9`	`14`
`10`	`15`	`#[divan::bench]`
`11`	`16`	`fn sleep_100ns() {`
`12`		`- std::thread::sleep(std::time::Duration::from_nanos(100));`
	`17`	`+ busy_sleep(std::time::Duration::from_nanos(100));`
`13`	`18`	`}`
`14`	`19`
`15`	`20`	`#[divan::bench]`
`16`	`21`	`fn sleep_1us() {`
`17`		`- std::thread::sleep(std::time::Duration::from_micros(1));`
	`22`	`+ busy_sleep(std::time::Duration::from_micros(1));`
`18`	`23`	`}`
`19`	`24`
`20`	`25`	`#[divan::bench]`
`21`	`26`	`fn sleep_100us() {`
`22`		`- std::thread::sleep(std::time::Duration::from_micros(100));`
	`27`	`+ busy_sleep(std::time::Duration::from_micros(100));`
`23`	`28`	`}`
`24`	`29`
`25`	`30`	`#[divan::bench]`