1 files changed, 122 insertions, 0 deletions
diff --git a/third_party/rust/futures-util/benches_disabled/bilock.rs b/third_party/rust/futures-util/benches_disabled/bilock.rs
new file mode 100644
index 0000000000..417f75d31e
--- /dev/null
+++ b/third_party/rust/futures-util/benches_disabled/bilock.rs
@@ -0,0 +1,122 @@
+#![feature(test)]
+
+#[cfg(feature = "bilock")]
+mod bench {
+    use futures::executor::LocalPool;
+    use futures::task::{Context, Waker};
+    use futures_util::lock::BiLock;
+    use futures_util::lock::BiLockAcquire;
+    use futures_util::lock::BiLockAcquired;
+    use futures_util::task::ArcWake;
+
+    use std::sync::Arc;
+    use test::Bencher;
+
+    fn notify_noop() -> Waker {
+        struct Noop;
+
+        impl ArcWake for Noop {
+            fn wake(_: &Arc<Self>) {}
+        }
+
+        ArcWake::into_waker(Arc::new(Noop))
+    }
+
+    /// Pseudo-stream which simply calls `lock.poll()` on `poll`
+    struct LockStream {
+        lock: BiLockAcquire<u32>,
+    }
+
+    impl LockStream {
+        fn new(lock: BiLock<u32>) -> Self {
+            Self { lock: lock.lock() }
+        }
+
+        /// Release a lock after it was acquired in `poll`,
+        /// so `poll` could be called again.
+        fn release_lock(&mut self, guard: BiLockAcquired<u32>) {
+            self.lock = guard.unlock().lock()
+        }
+    }
+
+    impl Stream for LockStream {
+        type Item = BiLockAcquired<u32>;
+        type Error = ();
+
+        fn poll_next(&mut self, cx: &mut Context<'_>) -> Poll<Option<Self::Item>, Self::Error> {
+            self.lock.poll(cx).map(|a| a.map(Some))
+        }
+    }
+
+    #[bench]
+    fn contended(b: &mut Bencher) {
+        let pool = LocalPool::new();
+        let mut exec = pool.executor();
+        let waker = notify_noop();
+        let mut map = task::LocalMap::new();
+        let mut waker = task::Context::new(&mut map, &waker, &mut exec);
+
+        b.iter(|| {
+            let (x, y) = BiLock::new(1);
+
+            let mut x = LockStream::new(x);
+            let mut y = LockStream::new(y);
+
+            for _ in 0..1000 {
+                let x_guard = match x.poll_next(&mut waker) {
+                    Ok(Poll::Ready(Some(guard))) => guard,
+                    _ => panic!(),
+                };
+
+                // Try poll second lock while first lock still holds the lock
+                match y.poll_next(&mut waker) {
+                    Ok(Poll::Pending) => (),
+                    _ => panic!(),
+                };
+
+                x.release_lock(x_guard);
+
+                let y_guard = match y.poll_next(&mut waker) {
+                    Ok(Poll::Ready(Some(guard))) => guard,
+                    _ => panic!(),
+                };
+
+                y.release_lock(y_guard);
+            }
+            (x, y)
+        });
+    }
+
+    #[bench]
+    fn lock_unlock(b: &mut Bencher) {
+        let pool = LocalPool::new();
+        let mut exec = pool.executor();
+        let waker = notify_noop();
+        let mut map = task::LocalMap::new();
+        let mut waker = task::Context::new(&mut map, &waker, &mut exec);
+
+        b.iter(|| {
+            let (x, y) = BiLock::new(1);
+
+            let mut x = LockStream::new(x);
+            let mut y = LockStream::new(y);
+
+            for _ in 0..1000 {
+                let x_guard = match x.poll_next(&mut waker) {
+                    Ok(Poll::Ready(Some(guard))) => guard,
+                    _ => panic!(),
+                };
+
+                x.release_lock(x_guard);
+
+                let y_guard = match y.poll_next(&mut waker) {
+                    Ok(Poll::Ready(Some(guard))) => guard,
+                    _ => panic!(),
+                };
+
+                y.release_lock(y_guard);
+            }
+            (x, y)
+        })
+    }
+}