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#![feature(test)]
extern crate test;
use crate::test::Bencher;
use {
futures::{
channel::mpsc::{self, Sender, UnboundedSender},
ready,
sink::Sink,
stream::{Stream, StreamExt},
task::{Context, Poll},
},
futures_test::task::noop_context,
std::pin::Pin,
};
/// Single producer, single consumer
#[bench]
fn unbounded_1_tx(b: &mut Bencher) {
let mut cx = noop_context();
b.iter(|| {
let (tx, mut rx) = mpsc::unbounded();
// 1000 iterations to avoid measuring overhead of initialization
// Result should be divided by 1000
for i in 0..1000 {
// Poll, not ready, park
assert_eq!(Poll::Pending, rx.poll_next_unpin(&mut cx));
UnboundedSender::unbounded_send(&tx, i).unwrap();
// Now poll ready
assert_eq!(Poll::Ready(Some(i)), rx.poll_next_unpin(&mut cx));
}
})
}
/// 100 producers, single consumer
#[bench]
fn unbounded_100_tx(b: &mut Bencher) {
let mut cx = noop_context();
b.iter(|| {
let (tx, mut rx) = mpsc::unbounded();
let tx: Vec<_> = (0..100).map(|_| tx.clone()).collect();
// 1000 send/recv operations total, result should be divided by 1000
for _ in 0..10 {
for (i, x) in tx.iter().enumerate() {
assert_eq!(Poll::Pending, rx.poll_next_unpin(&mut cx));
UnboundedSender::unbounded_send(x, i).unwrap();
assert_eq!(Poll::Ready(Some(i)), rx.poll_next_unpin(&mut cx));
}
}
})
}
#[bench]
fn unbounded_uncontended(b: &mut Bencher) {
let mut cx = noop_context();
b.iter(|| {
let (tx, mut rx) = mpsc::unbounded();
for i in 0..1000 {
UnboundedSender::unbounded_send(&tx, i).expect("send");
// No need to create a task, because poll is not going to park.
assert_eq!(Poll::Ready(Some(i)), rx.poll_next_unpin(&mut cx));
}
})
}
/// A Stream that continuously sends incrementing number of the queue
struct TestSender {
tx: Sender<u32>,
last: u32, // Last number sent
}
// Could be a Future, it doesn't matter
impl Stream for TestSender {
type Item = u32;
fn poll_next(mut self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Option<Self::Item>> {
let this = &mut *self;
let mut tx = Pin::new(&mut this.tx);
ready!(tx.as_mut().poll_ready(cx)).unwrap();
tx.as_mut().start_send(this.last + 1).unwrap();
this.last += 1;
assert_eq!(Poll::Pending, tx.as_mut().poll_flush(cx));
Poll::Ready(Some(this.last))
}
}
/// Single producers, single consumer
#[bench]
fn bounded_1_tx(b: &mut Bencher) {
let mut cx = noop_context();
b.iter(|| {
let (tx, mut rx) = mpsc::channel(0);
let mut tx = TestSender { tx, last: 0 };
for i in 0..1000 {
assert_eq!(Poll::Ready(Some(i + 1)), tx.poll_next_unpin(&mut cx));
assert_eq!(Poll::Pending, tx.poll_next_unpin(&mut cx));
assert_eq!(Poll::Ready(Some(i + 1)), rx.poll_next_unpin(&mut cx));
}
})
}
/// 100 producers, single consumer
#[bench]
fn bounded_100_tx(b: &mut Bencher) {
let mut cx = noop_context();
b.iter(|| {
// Each sender can send one item after specified capacity
let (tx, mut rx) = mpsc::channel(0);
let mut tx: Vec<_> = (0..100).map(|_| TestSender { tx: tx.clone(), last: 0 }).collect();
for i in 0..10 {
for x in &mut tx {
// Send an item
assert_eq!(Poll::Ready(Some(i + 1)), x.poll_next_unpin(&mut cx));
// Then block
assert_eq!(Poll::Pending, x.poll_next_unpin(&mut cx));
// Recv the item
assert_eq!(Poll::Ready(Some(i + 1)), rx.poll_next_unpin(&mut cx));
}
}
})
}