39 lines
1.2 KiB
Rust
39 lines
1.2 KiB
Rust
//! Test if the OnceCell properly synchronizes.
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//! Needs to be run in release mode.
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//!
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//! We create a `Vec` with `N_ROUNDS` of `OnceCell`s. All threads will walk the `Vec`, and race to
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//! be the first one to initialize a cell.
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//! Every thread adds the results of the cells it sees to an accumulator, which is compared at the
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//! end.
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//! All threads should end up with the same result.
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use once_cell::sync::OnceCell;
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const N_THREADS: usize = 32;
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const N_ROUNDS: usize = 1_000_000;
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static CELLS: OnceCell<Vec<OnceCell<usize>>> = OnceCell::new();
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static RESULT: OnceCell<usize> = OnceCell::new();
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fn main() {
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let start = std::time::Instant::now();
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CELLS.get_or_init(|| vec![OnceCell::new(); N_ROUNDS]);
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let threads =
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(0..N_THREADS).map(|i| std::thread::spawn(move || thread_main(i))).collect::<Vec<_>>();
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for thread in threads {
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thread.join().unwrap();
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}
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println!("{:?}", start.elapsed());
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println!("No races detected");
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}
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fn thread_main(i: usize) {
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let cells = CELLS.get().unwrap();
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let mut accum = 0;
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for cell in cells.iter() {
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let &value = cell.get_or_init(|| i);
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accum += value;
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}
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assert_eq!(RESULT.get_or_init(|| accum), &accum);
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}
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