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use std::sync::atomic::Ordering::SeqCst;
use std::sync::atomic::{AtomicBool, AtomicUsize};
use std::sync::{Arc, Mutex};
use crossbeam_deque::Steal::{Empty, Success};
use crossbeam_deque::Worker;
use crossbeam_utils::thread::scope;
use rand::Rng;
#[test]
fn smoke() {
let w = Worker::new_lifo();
let s = w.stealer();
assert_eq!(w.pop(), None);
assert_eq!(s.steal(), Empty);
w.push(1);
assert_eq!(w.pop(), Some(1));
assert_eq!(w.pop(), None);
assert_eq!(s.steal(), Empty);
w.push(2);
assert_eq!(s.steal(), Success(2));
assert_eq!(s.steal(), Empty);
assert_eq!(w.pop(), None);
w.push(3);
w.push(4);
w.push(5);
assert_eq!(s.steal(), Success(3));
assert_eq!(s.steal(), Success(4));
assert_eq!(s.steal(), Success(5));
assert_eq!(s.steal(), Empty);
w.push(6);
w.push(7);
w.push(8);
w.push(9);
assert_eq!(w.pop(), Some(9));
assert_eq!(s.steal(), Success(6));
assert_eq!(w.pop(), Some(8));
assert_eq!(w.pop(), Some(7));
assert_eq!(w.pop(), None);
}
#[test]
fn is_empty() {
let w = Worker::new_lifo();
let s = w.stealer();
assert!(w.is_empty());
w.push(1);
assert!(!w.is_empty());
w.push(2);
assert!(!w.is_empty());
let _ = w.pop();
assert!(!w.is_empty());
let _ = w.pop();
assert!(w.is_empty());
assert!(s.is_empty());
w.push(1);
assert!(!s.is_empty());
w.push(2);
assert!(!s.is_empty());
let _ = s.steal();
assert!(!s.is_empty());
let _ = s.steal();
assert!(s.is_empty());
}
#[test]
fn spsc() {
#[cfg(miri)]
const STEPS: usize = 500;
#[cfg(not(miri))]
const STEPS: usize = 50_000;
let w = Worker::new_lifo();
let s = w.stealer();
scope(|scope| {
scope.spawn(|_| {
for i in 0..STEPS {
loop {
if let Success(v) = s.steal() {
assert_eq!(i, v);
break;
}
#[cfg(miri)]
std::hint::spin_loop();
}
}
assert_eq!(s.steal(), Empty);
});
for i in 0..STEPS {
w.push(i);
}
})
.unwrap();
}
#[test]
fn stampede() {
const THREADS: usize = 8;
#[cfg(miri)]
const COUNT: usize = 500;
#[cfg(not(miri))]
const COUNT: usize = 50_000;
let w = Worker::new_lifo();
for i in 0..COUNT {
w.push(Box::new(i + 1));
}
let remaining = Arc::new(AtomicUsize::new(COUNT));
scope(|scope| {
for _ in 0..THREADS {
let s = w.stealer();
let remaining = remaining.clone();
scope.spawn(move |_| {
let mut last = 0;
while remaining.load(SeqCst) > 0 {
if let Success(x) = s.steal() {
assert!(last < *x);
last = *x;
remaining.fetch_sub(1, SeqCst);
}
}
});
}
let mut last = COUNT + 1;
while remaining.load(SeqCst) > 0 {
if let Some(x) = w.pop() {
assert!(last > *x);
last = *x;
remaining.fetch_sub(1, SeqCst);
}
}
})
.unwrap();
}
#[test]
fn stress() {
const THREADS: usize = 8;
#[cfg(miri)]
const COUNT: usize = 500;
#[cfg(not(miri))]
const COUNT: usize = 50_000;
let w = Worker::new_lifo();
let done = Arc::new(AtomicBool::new(false));
let hits = Arc::new(AtomicUsize::new(0));
scope(|scope| {
for _ in 0..THREADS {
let s = w.stealer();
let done = done.clone();
let hits = hits.clone();
scope.spawn(move |_| {
let w2 = Worker::new_lifo();
while !done.load(SeqCst) {
if let Success(_) = s.steal() {
hits.fetch_add(1, SeqCst);
}
let _ = s.steal_batch(&w2);
if let Success(_) = s.steal_batch_and_pop(&w2) {
hits.fetch_add(1, SeqCst);
}
while w2.pop().is_some() {
hits.fetch_add(1, SeqCst);
}
}
});
}
let mut rng = rand::thread_rng();
let mut expected = 0;
while expected < COUNT {
if rng.gen_range(0..3) == 0 {
while w.pop().is_some() {
hits.fetch_add(1, SeqCst);
}
} else {
w.push(expected);
expected += 1;
}
}
while hits.load(SeqCst) < COUNT {
while w.pop().is_some() {
hits.fetch_add(1, SeqCst);
}
}
done.store(true, SeqCst);
})
.unwrap();
}
#[cfg_attr(miri, ignore)] // Miri is too slow
#[test]
fn no_starvation() {
const THREADS: usize = 8;
const COUNT: usize = 50_000;
let w = Worker::new_lifo();
let done = Arc::new(AtomicBool::new(false));
let mut all_hits = Vec::new();
scope(|scope| {
for _ in 0..THREADS {
let s = w.stealer();
let done = done.clone();
let hits = Arc::new(AtomicUsize::new(0));
all_hits.push(hits.clone());
scope.spawn(move |_| {
let w2 = Worker::new_lifo();
while !done.load(SeqCst) {
if let Success(_) = s.steal() {
hits.fetch_add(1, SeqCst);
}
let _ = s.steal_batch(&w2);
if let Success(_) = s.steal_batch_and_pop(&w2) {
hits.fetch_add(1, SeqCst);
}
while w2.pop().is_some() {
hits.fetch_add(1, SeqCst);
}
}
});
}
let mut rng = rand::thread_rng();
let mut my_hits = 0;
loop {
for i in 0..rng.gen_range(0..COUNT) {
if rng.gen_range(0..3) == 0 && my_hits == 0 {
while w.pop().is_some() {
my_hits += 1;
}
} else {
w.push(i);
}
}
if my_hits > 0 && all_hits.iter().all(|h| h.load(SeqCst) > 0) {
break;
}
}
done.store(true, SeqCst);
})
.unwrap();
}
#[test]
fn destructors() {
#[cfg(miri)]
const THREADS: usize = 2;
#[cfg(not(miri))]
const THREADS: usize = 8;
#[cfg(miri)]
const COUNT: usize = 500;
#[cfg(not(miri))]
const COUNT: usize = 50_000;
#[cfg(miri)]
const STEPS: usize = 100;
#[cfg(not(miri))]
const STEPS: usize = 1000;
struct Elem(usize, Arc<Mutex<Vec<usize>>>);
impl Drop for Elem {
fn drop(&mut self) {
self.1.lock().unwrap().push(self.0);
}
}
let w = Worker::new_lifo();
let dropped = Arc::new(Mutex::new(Vec::new()));
let remaining = Arc::new(AtomicUsize::new(COUNT));
for i in 0..COUNT {
w.push(Elem(i, dropped.clone()));
}
scope(|scope| {
for _ in 0..THREADS {
let remaining = remaining.clone();
let s = w.stealer();
scope.spawn(move |_| {
let w2 = Worker::new_lifo();
let mut cnt = 0;
while cnt < STEPS {
if let Success(_) = s.steal() {
cnt += 1;
remaining.fetch_sub(1, SeqCst);
}
let _ = s.steal_batch(&w2);
if let Success(_) = s.steal_batch_and_pop(&w2) {
cnt += 1;
remaining.fetch_sub(1, SeqCst);
}
while w2.pop().is_some() {
cnt += 1;
remaining.fetch_sub(1, SeqCst);
}
}
});
}
for _ in 0..STEPS {
if w.pop().is_some() {
remaining.fetch_sub(1, SeqCst);
}
}
})
.unwrap();
let rem = remaining.load(SeqCst);
assert!(rem > 0);
{
let mut v = dropped.lock().unwrap();
assert_eq!(v.len(), COUNT - rem);
v.clear();
}
drop(w);
{
let mut v = dropped.lock().unwrap();
assert_eq!(v.len(), rem);
v.sort_unstable();
for pair in v.windows(2) {
assert_eq!(pair[0] + 1, pair[1]);
}
}
}