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This commit is contained in:
ivmarkov 2022-09-26 13:46:15 +03:00
parent ba6e452cc5
commit 53608a87ac
4 changed files with 518 additions and 587 deletions
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16
embassy-time/Cargo.toml
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@ -26,10 +26,22 @@ unstable-traits = ["embedded-hal-1"]
# To use this you must have a time driver provided. # To use this you must have a time driver provided.
defmt-timestamp-uptime = ["defmt"] defmt-timestamp-uptime = ["defmt"]
# Create a global queue that can be used with any executor # Create a global, generic queue that can be used with any executor
# To use this you must have a time driver provided. # To use this you must have a time driver provided.
generic-queue = [] generic-queue = []
# Set the number of timers for the generic queue.
#
# At most 1 `generic-queue-*` feature can be enabled. If none is enabled, a default of 64 timers is used.
#
# When using embassy-time from libraries, you should *not* enable any `generic-queue-*` feature, to allow the
# end user to pick.
generic-queue-8 = ["generic-queue"]
generic-queue-16 = ["generic-queue"]
generic-queue-32 = ["generic-queue"]
generic-queue-64 = ["generic-queue"]
generic-queue-128 = ["generic-queue"]
# Set the `embassy_time` tick rate. # Set the `embassy_time` tick rate.
# #
# At most 1 `tick-*` feature can be enabled. If none is enabled, a default of 1MHz is used. # At most 1 `tick-*` feature can be enabled. If none is enabled, a default of 1MHz is used.
@ -128,3 +140,5 @@ wasm-timer = { version = "0.2.5", optional = true }
[dev-dependencies] [dev-dependencies]
serial_test = "0.9" serial_test = "0.9"
critical-section = { version = "1.1", features = ["std"] }

2
embassy-time/src/lib.rs
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@ -19,6 +19,8 @@ mod timer;
mod driver_std; mod driver_std;
#[cfg(feature = "wasm")] #[cfg(feature = "wasm")]
mod driver_wasm; mod driver_wasm;
#[cfg(feature = "generic-queue")]
mod queue_generic;
pub use delay::{block_for, Delay}; pub use delay::{block_for, Delay};
pub use duration::Duration; pub use duration::Duration;

613
embassy-time/src/queue.rs
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@ -1,617 +1,58 @@
//! Generic timer queue implementation //! Timer queue implementation
//! //!
//! This module provides a timer queue that works with any executor. //! This module defines the interface a timer queue needs to implement to power the `embassy_time` module.
//! //!
//! In terms of performance, this queue will likely be less efficient in comparison to executor-native queues, //! # Implementing a timer queue
//! like the one provided with e.g. the `embassy-executor` crate.
//! //!
//! # Enabling the queue //! - Define a struct `MyTimerQueue`
//! - Enable the Cargo feature `generic-queue`. This will automatically instantiate the queue. //! - Implement [`TimerQueue`] for it
//! - Register it as the global timer queue with [`timer_queue_impl`](crate::timer_queue_impl).
//! //!
//! # Initializing the queue //! # Linkage details
//! - Call ```unsafe { embassy_time::queue::initialize(); }``` early on in your program, before any of your futures that utilize `embassy-time` are polled.
//! //!
//! # Customizing the queue //! Check the documentation of the [`driver`](crate::driver) module for more information.
//! - It is possible to customize two aspects of the queue:
//! - Queue size:
//! By default, the queue can hold up to 128 timer schedules and their corresponding wakers. While it will not crash if more timer schedules are added,
//! the performance will degrade, as one of the already added wakers will be awoken, thus making room for the new timer schedule and its waker.
//! - The mutex (i.e. the [`RawMutex`](embassy_sync::blocking_mutex::raw::RawMutex) implementation) utilized by the queue:
//! By default, the utilized [`RawMutex`](embassy_sync::blocking_mutex::raw::RawMutex) implementation is [`CriticalSectionRawMutex`](embassy_sync::blocking_mutex::raw::CriticalSectionRawMutex)
//! which is provided by the `critical-section` crate. This should work just fine, except in a few niche cases like running on
//! top of an RTOS which provides a [`Driver`](crate::driver::Driver) implementation that will call-back directly from an ISR. As the
//! `critical-section` implementation for RTOS-es will likely provide an RTOS mutex which cannot be locked from an ISR, user needs to instead
//! configure the queue with a "disable-all-interrupts" style of mutex.
//! - To customize any of these queue aspects, don't enable the `generic-queue` Cargo feature and instead instantiate the queue with the [`generic_queue`](crate::generic_queue)
//! macro, as per the example below.
//! //!
//! Similarly to driver, if there is none or multiple timer queues in the crate tree, linking will fail.
//! //!
//! # Example //! # Example
//! //!
//! ```ignore //! ```
//! use embassy_time::queue::Queue; //! use core::task::Waker;
//! //!
//! // You only need to invoke this macro in case you need to customize the queue. //! use embassy_time::Instant;
//! // //! use embassy_time::queue::{TimerQueue};
//! // Otherwise, just depend on the `embassy-time` crate with feature `generic-queue` enabled,
//! // and the queue instantiation will be done for you behind the scenes.
//! embassy_time::generic_queue!(static QUEUE: Queue<200, MyCustomRawMutex> = Queue::new());
//! //!
//! fn main() { //! struct MyTimerQueue{}; // not public!
//! unsafe { //! embassy_time::timer_queue_impl!(static QUEUE: MyTimerQueue = MyTimerQueue{});
//! embassy_time::queue::initialize(); //!
//! impl TimerQueue for MyTimerQueue {
//! fn schedule_wake(&'static self, at: Instant, waker: &Waker) {
//! todo!()
//! } //! }
//! } //! }
//! ``` //! ```
use core::cell::{Cell, RefCell};
use core::cmp::Ordering;
use core::task::Waker; use core::task::Waker;
use atomic_polyfill::{AtomicU64, Ordering as AtomicOrdering};
use embassy_sync::blocking_mutex::raw::{CriticalSectionRawMutex, RawMutex};
use embassy_sync::blocking_mutex::Mutex;
use heapless::sorted_linked_list::{LinkedIndexU8, Min, SortedLinkedList};
use crate::driver::{allocate_alarm, set_alarm, set_alarm_callback, AlarmHandle};
use crate::Instant; use crate::Instant;
#[derive(Debug)] /// Timer queue
struct Timer { pub trait TimerQueue {
at: Instant, /// Schedules a waker in the queue to be awoken at moment `at`.
waker: Waker, /// If this moment is in the past, the waker might be awoken immediately.
fn schedule_wake(&'static self, at: Instant, waker: &Waker);
} }
impl PartialEq for Timer { /// Set the TimerQueue implementation.
fn eq(&self, other: &Self) -> bool {
self.at == other.at
}
}
impl Eq for Timer {}
impl PartialOrd for Timer {
fn partial_cmp(&self, other: &Self) -> Option<Ordering> {
self.at.partial_cmp(&other.at)
}
}
impl Ord for Timer {
fn cmp(&self, other: &Self) -> Ordering {
self.at.cmp(&other.at)
}
}
struct InnerQueue<const N: usize> {
queue: SortedLinkedList<Timer, LinkedIndexU8, Min, N>,
alarm_at: Instant,
}
impl<const N: usize> InnerQueue<N> {
const fn new() -> Self {
Self {
queue: SortedLinkedList::new_u8(),
alarm_at: Instant::MAX,
}
}
fn schedule(&mut self, at: Instant, waker: &Waker, alarm_schedule: &AtomicU64) {
self.queue
.find_mut(|timer| timer.waker.will_wake(waker))
.map(|mut timer| {
timer.waker = waker.clone();
timer.at = at;
timer.finish();
})
.unwrap_or_else(|| {
let mut timer = Timer {
waker: waker.clone(),
at,
};
loop {
match self.queue.push(timer) {
Ok(()) => break,
Err(e) => timer = e,
}
self.queue.pop().unwrap().waker.wake();
}
});
// Don't wait for the alarm callback to trigger and directly
// dispatch all timers that are already due
//
// Then update the alarm if necessary
self.dispatch(alarm_schedule);
}
fn dispatch(&mut self, alarm_schedule: &AtomicU64) {
let now = Instant::now();
while self.queue.peek().filter(|timer| timer.at <= now).is_some() {
self.queue.pop().unwrap().waker.wake();
}
self.update_alarm(alarm_schedule);
}
fn update_alarm(&mut self, alarm_schedule: &AtomicU64) {
if let Some(timer) = self.queue.peek() {
let new_at = timer.at;
if self.alarm_at != new_at {
self.alarm_at = new_at;
alarm_schedule.store(new_at.as_ticks(), AtomicOrdering::SeqCst);
}
} else {
self.alarm_at = Instant::MAX;
alarm_schedule.store(Instant::MAX.as_ticks(), AtomicOrdering::SeqCst);
}
}
fn handle_alarm(&mut self, alarm_schedule: &AtomicU64) {
self.alarm_at = Instant::MAX;
self.dispatch(alarm_schedule);
}
}
/// The generic queue implementation
pub struct Queue<const N: usize = 128, R: RawMutex = CriticalSectionRawMutex> {
inner: Mutex<R, RefCell<InnerQueue<N>>>,
alarm: Cell<Option<AlarmHandle>>,
alarm_schedule: AtomicU64,
}
impl<const N: usize, R: RawMutex + 'static> Queue<N, R> {
/// Create a Queue
pub const fn new() -> Self {
Self {
inner: Mutex::new(RefCell::new(InnerQueue::<N>::new())),
alarm: Cell::new(None),
alarm_schedule: AtomicU64::new(u64::MAX),
}
}
/// Initialize the queue
///
/// This method is called from [`initialize`](crate::queue::initialize), so you are not expected to call it directly.
/// Call [`initialize`](crate::queue::initialize) instead.
///
/// # Safety
/// It is UB call this function more than once, or to call it after any of your
/// futures that use `embassy-time` are polled already.
pub unsafe fn initialize(&'static self) {
if self.alarm.get().is_some() {
panic!("Queue is already initialized");
}
let handle = allocate_alarm().unwrap();
self.alarm.set(Some(handle));
set_alarm_callback(handle, Self::handle_alarm_callback, self as *const _ as _);
}
/// Schedule a new waker to be awoken at moment `at`
///
/// This method is called internally by [`embassy-time`](crate), so you are not expected to call it directly.
pub fn schedule(&'static self, at: Instant, waker: &Waker) {
self.check_initialized();
self.inner
.lock(|inner| inner.borrow_mut().schedule(at, waker, &self.alarm_schedule));
self.update_alarm();
}
fn check_initialized(&self) {
if self.alarm.get().is_none() {
panic!("Queue is not initialized yet");
}
}
fn update_alarm(&self) {
// Need to set the alarm when we are *not* holding the mutex on the inner queue
// because mutexes are not re-entrant, which is a problem because `set_alarm` might immediately
// call us back if the timestamp is in the past.
let alarm_at = self.alarm_schedule.swap(u64::MAX, AtomicOrdering::SeqCst);
if alarm_at < u64::MAX {
set_alarm(self.alarm.get().unwrap(), alarm_at);
}
}
fn handle_alarm(&self) {
self.check_initialized();
self.inner
.lock(|inner| inner.borrow_mut().handle_alarm(&self.alarm_schedule));
self.update_alarm();
}
fn handle_alarm_callback(ctx: *mut ()) {
unsafe { (ctx as *const Self).as_ref().unwrap() }.handle_alarm();
}
}
unsafe impl<const N: usize, R: RawMutex + 'static> Send for Queue<N, R> {}
unsafe impl<const N: usize, R: RawMutex + 'static> Sync for Queue<N, R> {}
/// Initialize the queue
///
/// Call this function early on in your program, before any of your futures that utilize `embassy-time` are polled.
///
/// # Safety
/// It is UB call this function more than once, or to call it after any of your
/// futures that use `embassy-time` are polled already.
pub unsafe fn initialize() {
extern "Rust" {
fn _embassy_time_generic_queue_initialize();
}
_embassy_time_generic_queue_initialize();
}
/// Instantiates a global, generic (as in executor-agnostic) timer queue.
///
/// Unless you plan to customize the queue (size or mutex), prefer
/// instantiating the queue via the `generic-queue` feature.
/// ///
/// See the module documentation for an example. /// See the module documentation for an example.
#[macro_export] #[macro_export]
macro_rules! generic_queue { macro_rules! timer_queue_impl {
(static $name:ident: $t: ty = $val:expr) => { (static $name:ident: $t: ty = $val:expr) => {
static $name: $t = $val; static $name: $t = $val;
#[no_mangle]
fn _embassy_time_generic_queue_initialize() {
unsafe {
$crate::queue::Queue::initialize(&$name);
}
}
#[no_mangle] #[no_mangle]
fn _embassy_time_schedule_wake(at: $crate::Instant, waker: &core::task::Waker) { fn _embassy_time_schedule_wake(at: $crate::Instant, waker: &core::task::Waker) {
$crate::queue::Queue::schedule(&$name, at, waker); <$t as $crate::queue::TimerQueue>::schedule_wake(&$name, at, waker);
} }
}; };
} }
#[cfg(feature = "generic-queue")]
generic_queue!(static QUEUE: Queue = Queue::new());
#[cfg(test)]
mod tests {
use core::cell::Cell;
use core::sync::atomic::Ordering;
use core::task::{RawWaker, RawWakerVTable, Waker};
use std::rc::Rc;
use std::sync::Mutex;
use embassy_sync::blocking_mutex::raw::RawMutex;
use serial_test::serial;
use super::InnerQueue;
use crate::driver::{AlarmHandle, Driver};
use crate::Instant;
struct InnerTestDriver {
now: u64,
alarm: u64,
callback: fn(*mut ()),
ctx: *mut (),
}
impl InnerTestDriver {
const fn new() -> Self {
Self {
now: 0,
alarm: u64::MAX,
callback: Self::noop,
ctx: core::ptr::null_mut(),
}
}
fn noop(_ctx: *mut ()) {}
}
unsafe impl Send for InnerTestDriver {}
struct TestDriver(Mutex<InnerTestDriver>);
impl TestDriver {
const fn new() -> Self {
Self(Mutex::new(InnerTestDriver::new()))
}
fn reset(&self) {
*self.0.lock().unwrap() = InnerTestDriver::new();
}
fn set_now(&self, now: u64) {
let notify = {
let mut inner = self.0.lock().unwrap();
if inner.now < now {
inner.now = now;
if inner.alarm <= now {
inner.alarm = u64::MAX;
Some((inner.callback, inner.ctx))
} else {
None
}
} else {
panic!("Going back in time?");
}
};
if let Some((callback, ctx)) = notify {
(callback)(ctx);
}
}
}
impl Driver for TestDriver {
fn now(&self) -> u64 {
self.0.lock().unwrap().now
}
unsafe fn allocate_alarm(&self) -> Option<AlarmHandle> {
Some(AlarmHandle::new(0))
}
fn set_alarm_callback(&self, _alarm: AlarmHandle, callback: fn(*mut ()), ctx: *mut ()) {
let mut inner = self.0.lock().unwrap();
inner.callback = callback;
inner.ctx = ctx;
}
fn set_alarm(&self, _alarm: AlarmHandle, timestamp: u64) {
let notify = {
let mut inner = self.0.lock().unwrap();
if timestamp <= inner.now {
Some((inner.callback, inner.ctx))
} else {
inner.alarm = timestamp;
None
}
};
if let Some((callback, ctx)) = notify {
(callback)(ctx);
}
}
}
struct TestWaker {
pub awoken: Rc<Cell<bool>>,
pub waker: Waker,
}
impl TestWaker {
fn new() -> Self {
let flag = Rc::new(Cell::new(false));
const VTABLE: RawWakerVTable = RawWakerVTable::new(
|data: *const ()| {
unsafe {
Rc::increment_strong_count(data as *const Cell<bool>);
}
RawWaker::new(data as _, &VTABLE)
},
|data: *const ()| unsafe {
let data = data as *const Cell<bool>;
data.as_ref().unwrap().set(true);
Rc::decrement_strong_count(data);
},
|data: *const ()| unsafe {
(data as *const Cell<bool>).as_ref().unwrap().set(true);
},
|data: *const ()| unsafe {
Rc::decrement_strong_count(data);
},
);
let raw = RawWaker::new(Rc::into_raw(flag.clone()) as _, &VTABLE);
Self {
awoken: flag.clone(),
waker: unsafe { Waker::from_raw(raw) },
}
}
}
// TODO: This impl should be part of `embassy-sync`, hidden behind the "std" feature gate
pub struct StdRawMutex(std::sync::Mutex<()>);
unsafe impl RawMutex for StdRawMutex {
const INIT: Self = StdRawMutex(std::sync::Mutex::new(()));
fn lock<R>(&self, f: impl FnOnce() -> R) -> R {
let _guard = self.0.lock().unwrap();
f()
}
}
const QUEUE_MAX_LEN: usize = 8;
crate::time_driver_impl!(static DRIVER: TestDriver = TestDriver::new());
crate::generic_queue!(static QUEUE: super::Queue<{ QUEUE_MAX_LEN }, StdRawMutex> = super::Queue::new());
fn setup() {
DRIVER.reset();
QUEUE.alarm.set(None);
QUEUE.alarm_schedule.store(u64::MAX, Ordering::SeqCst);
QUEUE.inner.lock(|inner| {
*inner.borrow_mut() = InnerQueue::new();
});
unsafe { super::initialize() };
}
fn queue_len() -> usize {
QUEUE.inner.lock(|inner| inner.borrow().queue.iter().count())
}
#[test]
#[serial]
#[should_panic(expected = "Queue is not initialized yet")]
fn test_not_initialized() {
static QUEUE: super::Queue<{ QUEUE_MAX_LEN }, StdRawMutex> = super::Queue::new();
let waker = TestWaker::new();
QUEUE.schedule(Instant::from_secs(1), &waker.waker);
}
#[test]
#[serial]
fn test_initialized() {
static QUEUE: super::Queue<{ QUEUE_MAX_LEN }, StdRawMutex> = super::Queue::new();
assert!(QUEUE.alarm.get().is_none());
unsafe { QUEUE.initialize() };
assert!(QUEUE.alarm.get().is_some());
}
#[test]
#[serial]
#[should_panic(expected = "Queue is already initialized")]
fn test_already_initialized() {
static QUEUE: super::Queue<{ QUEUE_MAX_LEN }, StdRawMutex> = super::Queue::new();
unsafe { QUEUE.initialize() };
assert!(QUEUE.alarm.get().is_some());
unsafe { QUEUE.initialize() };
}
#[test]
#[serial]
fn test_schedule() {
setup();
assert_eq!(queue_len(), 0);
let waker = TestWaker::new();
QUEUE.schedule(Instant::from_secs(1), &waker.waker);
assert!(!waker.awoken.get());
assert_eq!(queue_len(), 1);
}
#[test]
#[serial]
fn test_schedule_same() {
setup();
let waker = TestWaker::new();
QUEUE.schedule(Instant::from_secs(1), &waker.waker);
assert_eq!(queue_len(), 1);
QUEUE.schedule(Instant::from_secs(1), &waker.waker);
assert_eq!(queue_len(), 1);
QUEUE.schedule(Instant::from_secs(100), &waker.waker);
assert_eq!(queue_len(), 1);
let waker2 = TestWaker::new();
QUEUE.schedule(Instant::from_secs(100), &waker2.waker);
assert_eq!(queue_len(), 2);
}
#[test]
#[serial]
fn test_trigger() {
setup();
let waker = TestWaker::new();
QUEUE.schedule(Instant::from_secs(100), &waker.waker);
assert!(!waker.awoken.get());
DRIVER.set_now(Instant::from_secs(99).as_ticks());
assert!(!waker.awoken.get());
assert_eq!(queue_len(), 1);
DRIVER.set_now(Instant::from_secs(100).as_ticks());
assert!(waker.awoken.get());
assert_eq!(queue_len(), 0);
}
#[test]
#[serial]
fn test_immediate_trigger() {
setup();
let waker = TestWaker::new();
QUEUE.schedule(Instant::from_secs(100), &waker.waker);
DRIVER.set_now(Instant::from_secs(50).as_ticks());
let waker2 = TestWaker::new();
QUEUE.schedule(Instant::from_secs(40), &waker2.waker);
assert!(!waker.awoken.get());
assert!(waker2.awoken.get());
assert_eq!(queue_len(), 1);
}
#[test]
#[serial]
fn test_queue_overflow() {
setup();
for i in 1..QUEUE_MAX_LEN {
let waker = TestWaker::new();
QUEUE.schedule(Instant::from_secs(310), &waker.waker);
assert_eq!(queue_len(), i);
assert!(!waker.awoken.get());
}
let first_waker = TestWaker::new();
QUEUE.schedule(Instant::from_secs(300), &first_waker.waker);
assert_eq!(queue_len(), QUEUE_MAX_LEN);
assert!(!first_waker.awoken.get());
let second_waker = TestWaker::new();
QUEUE.schedule(Instant::from_secs(305), &second_waker.waker);
assert_eq!(queue_len(), QUEUE_MAX_LEN);
assert!(first_waker.awoken.get());
QUEUE.schedule(Instant::from_secs(320), &TestWaker::new().waker);
assert_eq!(queue_len(), QUEUE_MAX_LEN);
assert!(second_waker.awoken.get());
}
}

474
embassy-time/src/queue_generic.rs Normal file
View File

@ -0,0 +1,474 @@
use core::cell::RefCell;
use core::cmp::Ordering;
use core::task::Waker;
use atomic_polyfill::{AtomicU64, Ordering as AtomicOrdering};
use embassy_sync::blocking_mutex::raw::CriticalSectionRawMutex;
use embassy_sync::blocking_mutex::Mutex;
use heapless::sorted_linked_list::{LinkedIndexU8, Min, SortedLinkedList};
use crate::driver::{allocate_alarm, set_alarm, set_alarm_callback, AlarmHandle};
use crate::queue::TimerQueue;
use crate::Instant;
#[cfg(feature = "generic-queue-8")]
const QUEUE_SIZE: usize = 8;
#[cfg(feature = "generic-queue-16")]
const QUEUE_SIZE: usize = 16;
#[cfg(feature = "generic-queue-32")]
const QUEUE_SIZE: usize = 32;
#[cfg(feature = "generic-queue-64")]
const QUEUE_SIZE: usize = 32;
#[cfg(feature = "generic-queue-128")]
const QUEUE_SIZE: usize = 128;
#[cfg(not(any(
feature = "generic-queue-8",
feature = "generic-queue-16",
feature = "generic-queue-32",
feature = "generic-queue-64",
feature = "generic-queue-128"
)))]
const QUEUE_SIZE: usize = 64;
#[derive(Debug)]
struct Timer {
at: Instant,
waker: Waker,
}
impl PartialEq for Timer {
fn eq(&self, other: &Self) -> bool {
self.at == other.at
}
}
impl Eq for Timer {}
impl PartialOrd for Timer {
fn partial_cmp(&self, other: &Self) -> Option<Ordering> {
self.at.partial_cmp(&other.at)
}
}
impl Ord for Timer {
fn cmp(&self, other: &Self) -> Ordering {
self.at.cmp(&other.at)
}
}
struct InnerQueue {
queue: SortedLinkedList<Timer, LinkedIndexU8, Min, { QUEUE_SIZE }>,
alarm: Option<AlarmHandle>,
alarm_at: Instant,
}
impl InnerQueue {
const fn new() -> Self {
Self {
queue: SortedLinkedList::new_u8(),
alarm: None,
alarm_at: Instant::MAX,
}
}
fn schedule_wake(&mut self, at: Instant, waker: &Waker, alarm_schedule: &AtomicU64) {
self.queue
.find_mut(|timer| timer.waker.will_wake(waker))
.map(|mut timer| {
timer.at = at;
timer.finish();
})
.unwrap_or_else(|| {
let mut timer = Timer {
waker: waker.clone(),
at,
};
loop {
match self.queue.push(timer) {
Ok(()) => break,
Err(e) => timer = e,
}
self.queue.pop().unwrap().waker.wake();
}
});
// Don't wait for the alarm callback to trigger and directly
// dispatch all timers that are already due
//
// Then update the alarm if necessary
self.dispatch(alarm_schedule);
}
fn dispatch(&mut self, alarm_schedule: &AtomicU64) {
let now = Instant::now();
while self.queue.peek().filter(|timer| timer.at <= now).is_some() {
self.queue.pop().unwrap().waker.wake();
}
self.update_alarm(alarm_schedule);
}
fn update_alarm(&mut self, alarm_schedule: &AtomicU64) {
if let Some(timer) = self.queue.peek() {
let new_at = timer.at;
if self.alarm_at != new_at {
self.alarm_at = new_at;
alarm_schedule.store(new_at.as_ticks(), AtomicOrdering::SeqCst);
}
} else {
self.alarm_at = Instant::MAX;
alarm_schedule.store(Instant::MAX.as_ticks(), AtomicOrdering::SeqCst);
}
}
fn handle_alarm(&mut self, alarm_schedule: &AtomicU64) {
self.alarm_at = Instant::MAX;
self.dispatch(alarm_schedule);
}
}
struct Queue {
inner: Mutex<CriticalSectionRawMutex, RefCell<InnerQueue>>,
alarm_schedule: AtomicU64,
}
impl Queue {
const fn new() -> Self {
Self {
inner: Mutex::new(RefCell::new(InnerQueue::new())),
alarm_schedule: AtomicU64::new(u64::MAX),
}
}
fn schedule_wake(&'static self, at: Instant, waker: &Waker) {
self.inner.lock(|inner| {
let mut inner = inner.borrow_mut();
if inner.alarm.is_none() {
let handle = unsafe { allocate_alarm() }.unwrap();
inner.alarm = Some(handle);
set_alarm_callback(handle, Self::handle_alarm_callback, self as *const _ as _);
}
inner.schedule_wake(at, waker, &self.alarm_schedule)
});
self.update_alarm();
}
fn update_alarm(&self) {
// Need to set the alarm when we are *not* holding the mutex on the inner queue
// because mutexes are not re-entrant, which is a problem because `set_alarm` might immediately
// call us back if the timestamp is in the past.
let alarm_at = self.alarm_schedule.swap(u64::MAX, AtomicOrdering::SeqCst);
if alarm_at < u64::MAX {
set_alarm(self.inner.lock(|inner| inner.borrow().alarm.unwrap()), alarm_at);
}
}
fn handle_alarm(&self) {
self.inner
.lock(|inner| inner.borrow_mut().handle_alarm(&self.alarm_schedule));
self.update_alarm();
}
fn handle_alarm_callback(ctx: *mut ()) {
unsafe { (ctx as *const Self).as_ref().unwrap() }.handle_alarm();
}
}
impl TimerQueue for Queue {
fn schedule_wake(&'static self, at: Instant, waker: &Waker) {
Queue::schedule_wake(self, at, waker);
}
}
crate::timer_queue_impl!(static QUEUE: Queue = Queue::new());
#[cfg(test)]
mod tests {
use core::cell::Cell;
use core::sync::atomic::Ordering;
use core::task::{RawWaker, RawWakerVTable, Waker};
use std::rc::Rc;
use std::sync::Mutex;
use serial_test::serial;
use super::InnerQueue;
use crate::driver::{AlarmHandle, Driver};
use crate::queue_generic::QUEUE;
use crate::Instant;
struct InnerTestDriver {
now: u64,
alarm: u64,
callback: fn(*mut ()),
ctx: *mut (),
}
impl InnerTestDriver {
const fn new() -> Self {
Self {
now: 0,
alarm: u64::MAX,
callback: Self::noop,
ctx: core::ptr::null_mut(),
}
}
fn noop(_ctx: *mut ()) {}
}
unsafe impl Send for InnerTestDriver {}
struct TestDriver(Mutex<InnerTestDriver>);
impl TestDriver {
const fn new() -> Self {
Self(Mutex::new(InnerTestDriver::new()))
}
fn reset(&self) {
*self.0.lock().unwrap() = InnerTestDriver::new();
}
fn set_now(&self, now: u64) {
let notify = {
let mut inner = self.0.lock().unwrap();
if inner.now < now {
inner.now = now;
if inner.alarm <= now {
inner.alarm = u64::MAX;
Some((inner.callback, inner.ctx))
} else {
None
}
} else {
panic!("Going back in time?");
}
};
if let Some((callback, ctx)) = notify {
(callback)(ctx);
}
}
}
impl Driver for TestDriver {
fn now(&self) -> u64 {
self.0.lock().unwrap().now
}
unsafe fn allocate_alarm(&self) -> Option<AlarmHandle> {
Some(AlarmHandle::new(0))
}
fn set_alarm_callback(&self, _alarm: AlarmHandle, callback: fn(*mut ()), ctx: *mut ()) {
let mut inner = self.0.lock().unwrap();
inner.callback = callback;
inner.ctx = ctx;
}
fn set_alarm(&self, _alarm: AlarmHandle, timestamp: u64) {
let notify = {
let mut inner = self.0.lock().unwrap();
if timestamp <= inner.now {
Some((inner.callback, inner.ctx))
} else {
inner.alarm = timestamp;
None
}
};
if let Some((callback, ctx)) = notify {
(callback)(ctx);
}
}
}
struct TestWaker {
pub awoken: Rc<Cell<bool>>,
pub waker: Waker,
}
impl TestWaker {
fn new() -> Self {
let flag = Rc::new(Cell::new(false));
const VTABLE: RawWakerVTable = RawWakerVTable::new(
|data: *const ()| {
unsafe {
Rc::increment_strong_count(data as *const Cell<bool>);
}
RawWaker::new(data as _, &VTABLE)
},
|data: *const ()| unsafe {
let data = data as *const Cell<bool>;
data.as_ref().unwrap().set(true);
Rc::decrement_strong_count(data);
},
|data: *const ()| unsafe {
(data as *const Cell<bool>).as_ref().unwrap().set(true);
},
|data: *const ()| unsafe {
Rc::decrement_strong_count(data);
},
);
let raw = RawWaker::new(Rc::into_raw(flag.clone()) as _, &VTABLE);
Self {
awoken: flag.clone(),
waker: unsafe { Waker::from_raw(raw) },
}
}
}
crate::time_driver_impl!(static DRIVER: TestDriver = TestDriver::new());
fn setup() {
DRIVER.reset();
QUEUE.alarm_schedule.store(u64::MAX, Ordering::SeqCst);
QUEUE.inner.lock(|inner| {
*inner.borrow_mut() = InnerQueue::new();
});
}
fn queue_len() -> usize {
QUEUE.inner.lock(|inner| inner.borrow().queue.iter().count())
}
#[test]
#[serial]
fn test_schedule() {
setup();
assert_eq!(queue_len(), 0);
let waker = TestWaker::new();
QUEUE.schedule_wake(Instant::from_secs(1), &waker.waker);
assert!(!waker.awoken.get());
assert_eq!(queue_len(), 1);
}
#[test]
#[serial]
fn test_schedule_same() {
setup();
let waker = TestWaker::new();
QUEUE.schedule_wake(Instant::from_secs(1), &waker.waker);
assert_eq!(queue_len(), 1);
QUEUE.schedule_wake(Instant::from_secs(1), &waker.waker);
assert_eq!(queue_len(), 1);
QUEUE.schedule_wake(Instant::from_secs(100), &waker.waker);
assert_eq!(queue_len(), 1);
let waker2 = TestWaker::new();
QUEUE.schedule_wake(Instant::from_secs(100), &waker2.waker);
assert_eq!(queue_len(), 2);
}
#[test]
#[serial]
fn test_trigger() {
setup();
let waker = TestWaker::new();
QUEUE.schedule_wake(Instant::from_secs(100), &waker.waker);
assert!(!waker.awoken.get());
DRIVER.set_now(Instant::from_secs(99).as_ticks());
assert!(!waker.awoken.get());
assert_eq!(queue_len(), 1);
DRIVER.set_now(Instant::from_secs(100).as_ticks());
assert!(waker.awoken.get());
assert_eq!(queue_len(), 0);
}
#[test]
#[serial]
fn test_immediate_trigger() {
setup();
let waker = TestWaker::new();
QUEUE.schedule_wake(Instant::from_secs(100), &waker.waker);
DRIVER.set_now(Instant::from_secs(50).as_ticks());
let waker2 = TestWaker::new();
QUEUE.schedule_wake(Instant::from_secs(40), &waker2.waker);
assert!(!waker.awoken.get());
assert!(waker2.awoken.get());
assert_eq!(queue_len(), 1);
}
#[test]
#[serial]
fn test_queue_overflow() {
setup();
for i in 1..super::QUEUE_SIZE {
let waker = TestWaker::new();
QUEUE.schedule_wake(Instant::from_secs(310), &waker.waker);
assert_eq!(queue_len(), i);
assert!(!waker.awoken.get());
}
let first_waker = TestWaker::new();
QUEUE.schedule_wake(Instant::from_secs(300), &first_waker.waker);
assert_eq!(queue_len(), super::QUEUE_SIZE);
assert!(!first_waker.awoken.get());
let second_waker = TestWaker::new();
QUEUE.schedule_wake(Instant::from_secs(305), &second_waker.waker);
assert_eq!(queue_len(), super::QUEUE_SIZE);
assert!(first_waker.awoken.get());
QUEUE.schedule_wake(Instant::from_secs(320), &TestWaker::new().waker);
assert_eq!(queue_len(), super::QUEUE_SIZE);
assert!(second_waker.awoken.get());
}
}