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perf(semaphore): Allocate wake buffer only when needed #188

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Merged
tisonkun merged 2 commits into from
Aug 26, 2026
Merged

perf(semaphore): Allocate wake buffer only when needed #188

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2a5bb54
perf(semaphore): Allocate wake buffer only when needed
mhambre Aug 25, 2026
6af0799
Merge branch 'main' into perf/minor-semaphore-optimization
mhambre Aug 25, 2026
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6 changes: 5 additions & 1 deletion asyncband/src/internal/semaphore.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -177,7 +177,7 @@ impl Semaphore {
waiters: MutexGuard<'_, WaitList<WaitNode>>,
) {
const NUM_WAKER: usize = 32;
let mut wakers = Vec::with_capacity(NUM_WAKER);
let mut wakers = Vec::new();

let mut lock = Some(waiters);
while rem > 0 {
Expand All @@ -198,6 +198,10 @@ impl Semaphore {
Some((id, waiter)) => {
let remove_now = waiter.waker.is_none();
if let Some(waker) = waiter.waker.take() {
// Only allocate when we have an actual waker to store.
if wakers.is_empty() {
wakers.reserve(NUM_WAKER);
}
wakers.push(waker);
}
if remove_now {
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