mirror of
https://github.com/rust-lang/rust.git
synced 2025-06-05 11:48:30 +00:00
cbe5e7bc62
Use semaphores for thread parking on Apple platforms Currently we use a mutex-condvar pair for thread parking on Apple systems. Unfortunately, `pthread_cond_timedwait` uses the real-time clock for measuring time, which causes problems when the system time changes. The parking implementation in this PR uses a semaphore instead, which measures monotonic time by default, avoiding these issues. As a further benefit, this has the potential to improve performance a bit, since `unpark` does not need to wait for a lock to be released. Since the Mach semaphores are poorly documented (I could not find availability or stability guarantees for instance), this uses a [dispatch semaphore](https://developer.apple.com/documentation/dispatch/dispatch_semaphore?language=objc) instead. While it adds a layer of indirection (it uses Mach semaphores internally), the overhead is probably negligible. Tested on macOS 12.5. r? ``````@thomcc`````` |
||
|---|---|---|
| .. | ||
| common | ||
| hermit | ||
| itron | ||
| sgx | ||
| solid | ||
| unix | ||
| unsupported | ||
| wasi | ||
| wasm | ||
| windows | ||
| mod.rs | ||