Re-work time adjustments

src/interval.rs

@@ -35,6 +35,7 @@ pub struct Interval<T=PlatformTimer> {
     timer: T,
     ///Timer interval, change to this value will be reflected on next restart of timer.
     pub interval: time::Duration,
+    finish_at: time::Instant,
 }
 
 impl Interval {
@@ -50,6 +51,7 @@ impl<T: Timer> Interval<T> {
     pub fn new(interval: time::Duration) -> Self {
         Self {
             timer: T::new(interval),
+            finish_at: time::Instant::now() + interval,
             interval,
         }
     }
@@ -62,7 +64,12 @@ impl<T: Timer> Interval<T> {
 
     ///Restarts interval
     pub fn restart(&mut self) {
-        let interval = self.interval;
+        let now = time::Instant::now();
+
+        let interval = match now.checked_duration_since(self.finish_at) {
+            Some(delayed) => self.interval - time::Duration::from_nanos((delayed.as_nanos() % self.interval.as_nanos()) as _),
+            None => self.interval
+        };
         self.timer.restart(interval);
     }
 

tests/interval.rs

@@ -23,7 +23,7 @@ async fn test_interval() {
 }
 
 async fn test_interval_average(num_runs: usize, interval: time::Duration) {
-    let mut times = Vec::with_capacity(6000);
+    let mut times = Vec::with_capacity(num_runs);
 
     println!("interval={:?}", interval);
     let mut timer = async_timer::interval(interval);
@@ -52,10 +52,10 @@ async fn test_interval_average(num_runs: usize, interval: time::Duration) {
 
 #[tokio::test]
 async fn test_average_of_small_interval() {
-    test_interval_average(600, time::Duration::from_secs_f32(1. / 120.)).await;
+    test_interval_average(6000, time::Duration::from_secs_f32(1. / 120.)).await;
 }
 
 #[tokio::test]
 async fn test_average_of_mid_interval() {
-    test_interval_average(10, time::Duration::from_secs_f32(135. / 120.)).await;
+    test_interval_average(60, time::Duration::from_secs_f32(135. / 120.)).await;
 }