34 lines
1.1 KiB
Rust
34 lines
1.1 KiB
Rust
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// ignore-windows: Concurrency on Windows is not supported yet.
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use std::thread;
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use std::sync::atomic::{AtomicUsize, Ordering};
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static FLAG: AtomicUsize = AtomicUsize::new(0);
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// When a thread yields, Miri's scheduler used to pick the thread with the lowest ID
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// that can run. IDs are assigned in thread creation order.
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// This means we could make 2 threads infinitely ping-pong with each other while
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// really there is a 3rd thread that we should schedule to make progress.
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fn main() {
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let waiter1 = thread::spawn(|| {
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while FLAG.load(Ordering::Acquire) == 0 {
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// spin and wait
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thread::yield_now();
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}
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});
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let waiter2 = thread::spawn(|| {
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while FLAG.load(Ordering::Acquire) == 0 {
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// spin and wait
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thread::yield_now();
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}
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});
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let progress = thread::spawn(|| {
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FLAG.store(1, Ordering::Release);
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});
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// The first `join` blocks the main thread and thus takes it out of the equation.
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waiter1.join().unwrap();
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waiter2.join().unwrap();
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progress.join().unwrap();
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}
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