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#![warn(rust_2018_idioms)]
#![cfg(all(feature = "full", not(target_os = "wasi"), target_has_atomic = "64"))]
use std::sync::mpsc;
use std::time::Duration;
use tokio::runtime::Runtime;
use tokio::time;
#[test]
fn num_workers() {
let rt = current_thread();
assert_eq!(1, rt.metrics().num_workers());
let rt = threaded();
assert_eq!(2, rt.metrics().num_workers());
}
#[test]
fn num_alive_tasks() {
let rt = current_thread();
let metrics = rt.metrics();
assert_eq!(0, metrics.num_alive_tasks());
rt.block_on(rt.spawn(async move {
assert_eq!(1, metrics.num_alive_tasks());
}))
.unwrap();
assert_eq!(0, rt.metrics().num_alive_tasks());
let rt = threaded();
let metrics = rt.metrics();
assert_eq!(0, metrics.num_alive_tasks());
rt.block_on(rt.spawn(async move {
assert_eq!(1, metrics.num_alive_tasks());
}))
.unwrap();
// try for 10 seconds to see if this eventually succeeds.
// wake_join() is called before the task is released, so in multithreaded
// code, this means we sometimes exit the block_on before the counter decrements.
for _ in 0..100 {
if rt.metrics().num_alive_tasks() == 0 {
break;
}
std::thread::sleep(std::time::Duration::from_millis(100));
}
assert_eq!(0, rt.metrics().num_alive_tasks());
}
#[test]
fn global_queue_depth_current_thread() {
use std::thread;
let rt = current_thread();
let handle = rt.handle().clone();
let metrics = rt.metrics();
thread::spawn(move || {
handle.spawn(async {});
})
.join()
.unwrap();
assert_eq!(1, metrics.global_queue_depth());
}
#[test]
fn global_queue_depth_multi_thread() {
for _ in 0..10 {
let rt = threaded();
let metrics = rt.metrics();
if let Ok(_blocking_tasks) = try_block_threaded(&rt) {
for i in 0..10 {
assert_eq!(i, metrics.global_queue_depth());
rt.spawn(async {});
}
return;
}
}
panic!("exhausted every try to block the runtime");
}
#[test]
fn worker_total_busy_duration() {
const N: usize = 5;
let zero = Duration::from_millis(0);
let rt = current_thread();
let metrics = rt.metrics();
rt.block_on(async {
for _ in 0..N {
tokio::spawn(async {
tokio::task::yield_now().await;
})
.await
.unwrap();
}
});
drop(rt);
assert!(zero < metrics.worker_total_busy_duration(0));
let rt = threaded();
let metrics = rt.metrics();
rt.block_on(async {
for _ in 0..N {
tokio::spawn(async {
tokio::task::yield_now().await;
})
.await
.unwrap();
}
});
drop(rt);
for i in 0..metrics.num_workers() {
assert!(zero < metrics.worker_total_busy_duration(i));
}
}
#[test]
fn worker_park_count() {
let rt = current_thread();
let metrics = rt.metrics();
rt.block_on(async {
time::sleep(Duration::from_millis(1)).await;
});
drop(rt);
assert!(1 <= metrics.worker_park_count(0));
let rt = threaded();
let metrics = rt.metrics();
rt.block_on(async {
time::sleep(Duration::from_millis(1)).await;
});
drop(rt);
assert!(1 <= metrics.worker_park_count(0));
assert!(1 <= metrics.worker_park_count(1));
}
#[test]
fn worker_park_unpark_count() {
let rt = current_thread();
let metrics = rt.metrics();
rt.block_on(rt.spawn(async {})).unwrap();
drop(rt);
assert!(2 <= metrics.worker_park_unpark_count(0));
let rt = threaded();
let metrics = rt.metrics();
// Wait for workers to be parked after runtime startup.
for _ in 0..100 {
if 1 <= metrics.worker_park_unpark_count(0) && 1 <= metrics.worker_park_unpark_count(1) {
break;
}
std::thread::sleep(std::time::Duration::from_millis(100));
}
assert_eq!(1, metrics.worker_park_unpark_count(0));
assert_eq!(1, metrics.worker_park_unpark_count(1));
// Spawn a task to unpark and then park a worker.
rt.block_on(rt.spawn(async {})).unwrap();
for _ in 0..100 {
if 3 <= metrics.worker_park_unpark_count(0) || 3 <= metrics.worker_park_unpark_count(1) {
break;
}
std::thread::sleep(std::time::Duration::from_millis(100));
}
assert!(3 <= metrics.worker_park_unpark_count(0) || 3 <= metrics.worker_park_unpark_count(1));
// Both threads unpark for runtime shutdown.
drop(rt);
assert_eq!(0, metrics.worker_park_unpark_count(0) % 2);
assert_eq!(0, metrics.worker_park_unpark_count(1) % 2);
assert!(4 <= metrics.worker_park_unpark_count(0) || 4 <= metrics.worker_park_unpark_count(1));
}
fn try_block_threaded(rt: &Runtime) -> Result<Vec<mpsc::Sender<()>>, mpsc::RecvTimeoutError> {
let (tx, rx) = mpsc::channel();
let blocking_tasks = (0..rt.metrics().num_workers())
.map(|_| {
let tx = tx.clone();
let (task, barrier) = mpsc::channel();
// Spawn a task per runtime worker to block it.
rt.spawn(async move {
tx.send(()).ok();
barrier.recv().ok();
});
task
})
.collect();
// Make sure the previously spawned tasks are blocking the runtime by
// receiving a message from each blocking task.
//
// If this times out we were unsuccessful in blocking the runtime and hit
// a deadlock instead (which might happen and is expected behaviour).
for _ in 0..rt.metrics().num_workers() {
rx.recv_timeout(Duration::from_secs(1))?;
}
// Return senders of the mpsc channels used for blocking the runtime as a
// surrogate handle for the tasks. Sending a message or dropping the senders
// will unblock the runtime.
Ok(blocking_tasks)
}
fn current_thread() -> Runtime {
tokio::runtime::Builder::new_current_thread()
.enable_all()
.build()
.unwrap()
}
fn threaded() -> Runtime {
tokio::runtime::Builder::new_multi_thread()
.worker_threads(2)
.enable_all()
.build()
.unwrap()
}
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