missing-spin-loop

Require a processor hint in atomic busy-wait loops

An atomic polling loop that performs no other work repeatedly reloads the atomic value without informing the processor that it is spinning.
Instead, you SHOULD call spinLoop during bounded optimistic spinning or use a blocking synchronization operation for longer waits.

- Category: performance
- Level: warning
- Fix: none
- Scope: module

Reported

import { Atomic } from "destack:sync";

function wait(ready: &readonly Atomic<boolean>): void {
    while (!ready.load()) {}
}
Accepted

import { spinLoop } from "destack:hint";
import { Atomic } from "destack:sync";

function wait(ready: &readonly Atomic<boolean>): void {
    while (!ready.load()) {
        spinLoop();
    }
}
Prior art

- Clippy · missingspinloop

language/linter/src/rules/performance/missingspinloop.rs:8