feat: Optimize for timer timeout extension

in case we constantly extend the same timer the
head might already point to the timer we want
to cancel. in this case we can directly remove the
timer to reduce building up the heap unnecessarily.

Author: cmeissl

.github/workflows/ci.yml

@@ -131,6 +131,20 @@ jobs:
           command: update
           args: --package log --precise 0.4.16
 
+      - name: Downgrade regex
+        uses: actions-rs/cargo@v1
+        if: ${{ matrix.rust == '1.63.0' }}
+        with:
+          command: update
+          args: --package regex --precise 1.9.6
+
+      - name: Downgrade half
+        uses: actions-rs/cargo@v1
+        if: ${{ matrix.rust == '1.63.0' || matrix.rust == '1.69.0' }}
+        with:
+          command: update
+          args: --package half --precise 2.2.1
+
       - name: Run tests
         uses: actions-rs/cargo@v1
         with:
@@ -174,6 +188,20 @@ jobs:
           toolchain: ${{ matrix.rust }}
           override: true
 
+      - name: Downgrade regex
+        uses: actions-rs/cargo@v1
+        if: ${{ matrix.rust == '1.63.0' }}
+        with:
+          command: update
+          args: --package regex --precise 1.9.6
+
+      - name: Downgrade half
+        uses: actions-rs/cargo@v1
+        if: ${{ matrix.rust == '1.63.0' }}
+        with:
+          command: update
+          args: --package half --precise 2.2.1
+
       - name: Run tests
         uses: actions-rs/cargo@v1
         with:

Cargo.toml

@@ -34,6 +34,7 @@ nix = { version = "0.29", default-features = false, features = ["signal"], optio
 [dev-dependencies]
 futures = "0.3.5"
 rustix = { version = "0.38", default-features = false, features = ["net"] }
+criterion = { version = "0.4" }
 
 [features]
 block_on = ["pin-utils"]
@@ -48,3 +49,7 @@ rustdoc-args = ["--cfg", "docsrs"]
 [[test]]
 name = "signals"
 harness = false
+
+[[bench]]
+name = "timer"
+harness = false

benches/timer.rs

@@ -0,0 +1,100 @@
+use std::time::Duration;
+
+use calloop::timer::TimeoutAction;
+use criterion::{criterion_group, criterion_main, Criterion};
+
+fn single(c: &mut Criterion) {
+    let mut event_loop = calloop::EventLoop::<()>::try_new().unwrap();
+    let loop_handle = event_loop.handle();
+
+    let timer = calloop::timer::Timer::from_duration(Duration::from_secs(60 * 10));
+    let mut timeout_token = loop_handle
+        .insert_source(timer, |_, _, _| TimeoutAction::Drop)
+        .unwrap();
+
+    c.bench_function("extend_single", |b| {
+        b.iter(|| {
+            loop_handle.remove(timeout_token);
+
+            let timer = calloop::timer::Timer::from_duration(Duration::from_secs(60 * 10));
+            timeout_token = loop_handle
+                .insert_source(timer, |_, _, _| TimeoutAction::Drop)
+                .unwrap();
+
+            event_loop.dispatch(Some(Duration::ZERO), &mut ()).unwrap();
+        });
+    });
+}
+
+fn mixed(c: &mut Criterion) {
+    let mut event_loop = calloop::EventLoop::<()>::try_new().unwrap();
+    let loop_handle = event_loop.handle();
+
+    let timer = calloop::timer::Timer::from_duration(Duration::from_secs(60 * 10 - 1));
+    loop_handle
+        .insert_source(timer, |_, _, _| TimeoutAction::Drop)
+        .unwrap();
+
+    let timer = calloop::timer::Timer::from_duration(Duration::from_secs(60 * 10));
+    let mut timeout_token = loop_handle
+        .insert_source(timer, |_, _, _| TimeoutAction::Drop)
+        .unwrap();
+
+    let timer = calloop::timer::Timer::from_duration(Duration::from_secs(90 * 10));
+    loop_handle
+        .insert_source(timer, |_, _, _| TimeoutAction::Drop)
+        .unwrap();
+
+    c.bench_function("extend_mixed", |b| {
+        b.iter(|| {
+            loop_handle.remove(timeout_token);
+
+            let timer = calloop::timer::Timer::from_duration(Duration::from_secs(60 * 10));
+            timeout_token = loop_handle
+                .insert_source(timer, |_, _, _| TimeoutAction::Drop)
+                .unwrap();
+
+            event_loop.dispatch(Some(Duration::ZERO), &mut ()).unwrap();
+        });
+    });
+}
+
+fn mixed_multiple(c: &mut Criterion) {
+    let mut event_loop = calloop::EventLoop::<()>::try_new().unwrap();
+    let loop_handle = event_loop.handle();
+
+    for _ in 0..1000 {
+        let timer = calloop::timer::Timer::from_duration(Duration::from_secs(60 * 10 - 1));
+        loop_handle
+            .insert_source(timer, |_, _, _| TimeoutAction::Drop)
+            .unwrap();
+    }
+
+    let timer = calloop::timer::Timer::from_duration(Duration::from_secs(60 * 10));
+    let mut timeout_token = loop_handle
+        .insert_source(timer, |_, _, _| TimeoutAction::Drop)
+        .unwrap();
+
+    for _ in 0..1000 {
+        let timer = calloop::timer::Timer::from_duration(Duration::from_secs(90 * 10));
+        loop_handle
+            .insert_source(timer, |_, _, _| TimeoutAction::Drop)
+            .unwrap();
+    }
+
+    c.bench_function("extend_mixed_many", |b| {
+        b.iter(|| {
+            loop_handle.remove(timeout_token);
+
+            let timer = calloop::timer::Timer::from_duration(Duration::from_secs(60 * 10));
+            timeout_token = loop_handle
+                .insert_source(timer, |_, _, _| TimeoutAction::Drop)
+                .unwrap();
+
+            event_loop.dispatch(Some(Duration::ZERO), &mut ()).unwrap();
+        });
+    });
+}
+
+criterion_group!(benches, single, mixed, mixed_multiple);
+criterion_main!(benches);

src/sources/timer.rs

@@ -229,8 +229,19 @@ impl TimerWheel {
     }
 
     pub(crate) fn cancel(&mut self, counter: u32) {
+        if self
+            .heap
+            .peek()
+            .map(|data| data.counter == counter)
+            .unwrap_or(false)
+        {
+            self.heap.pop();
+            return;
+        };
+
         self.heap
             .iter()
+            .rev()
             .find(|data| data.counter == counter)
             .map(|data| data.token.take());
     }
@@ -265,13 +276,15 @@ impl TimerWheel {
 // trait implementations for TimeoutData
 
 impl std::cmp::Ord for TimeoutData {
+    #[inline]
     fn cmp(&self, other: &Self) -> std::cmp::Ordering {
         // earlier values have priority
         self.deadline.cmp(&other.deadline).reverse()
     }
 }
 
 impl std::cmp::PartialOrd for TimeoutData {
+    #[inline]
     fn partial_cmp(&self, other: &Self) -> Option<std::cmp::Ordering> {
         Some(self.cmp(other))
     }
@@ -281,6 +294,7 @@ impl std::cmp::PartialOrd for TimeoutData {
 // and the type is private, so ignore its coverage
 impl std::cmp::PartialEq for TimeoutData {
     #[cfg_attr(feature = "nightly_coverage", coverage(off))]
+    #[inline]
     fn eq(&self, other: &Self) -> bool {
         self.deadline == other.deadline
     }