Skip to content

Commit

Permalink
remove point 2
Browse files Browse the repository at this point in the history
  • Loading branch information
yjhn committed Sep 7, 2022
1 parent f8b804f commit 70c4e57
Showing 1 changed file with 17 additions and 20 deletions.
37 changes: 17 additions & 20 deletions README.md
Original file line number Diff line number Diff line change
Expand Up @@ -33,45 +33,42 @@ in the Rust standard library:
require a dynamically allocated `Box` to hold OS-specific synchronization
primitives. The small size of `Mutex` in particular encourages the use
of fine-grained locks to increase parallelism.
2. Since they consist of just a single atomic variable, have constant
initializers and don't need destructors, these primitives can be used as
`static` global variables.
3. Uncontended lock acquisition and release is done through fast inline
2. Uncontended lock acquisition and release is done through fast inline
paths which only require a single atomic operation.
4. Microcontention (a contended lock with a short critical section) is
3. Microcontention (a contended lock with a short critical section) is
efficiently handled by spinning a few times while trying to acquire a
lock.
5. The locks are adaptive and will suspend a thread after a few failed spin
4. The locks are adaptive and will suspend a thread after a few failed spin
attempts. This makes the locks suitable for both long and short critical
sections.
6. `Condvar`, `RwLock` and `Once` work on Windows XP, unlike the standard
5. `Condvar`, `RwLock` and `Once` work on Windows XP, unlike the standard
library versions of those types.
7. `RwLock` takes advantage of hardware lock elision on processors that
6. `RwLock` takes advantage of hardware lock elision on processors that
support it, which can lead to huge performance wins with many readers.
This must be enabled with the `hardware-lock-elision` feature.
8. `RwLock` uses a task-fair locking policy, which avoids reader and writer
7. `RwLock` uses a task-fair locking policy, which avoids reader and writer
starvation, whereas the standard library version makes no guarantees.
9. `Condvar` is guaranteed not to produce spurious wakeups. A thread will
8. `Condvar` is guaranteed not to produce spurious wakeups. A thread will
only be woken up if it timed out or it was woken up by a notification.
10. `Condvar::notify_all` will only wake up a single thread and requeue the
9. `Condvar::notify_all` will only wake up a single thread and requeue the
rest to wait on the associated `Mutex`. This avoids a thundering herd
problem where all threads try to acquire the lock at the same time.
11. `RwLock` supports atomically downgrading a write lock into a read lock.
12. `Mutex` and `RwLock` allow raw unlocking without a RAII guard object.
13. `Mutex<()>` and `RwLock<()>` allow raw locking without a RAII guard
10. `RwLock` supports atomically downgrading a write lock into a read lock.
11. `Mutex` and `RwLock` allow raw unlocking without a RAII guard object.
12. `Mutex<()>` and `RwLock<()>` allow raw locking without a RAII guard
object.
14. `Mutex` and `RwLock` support [eventual fairness](https://trac.webkit.org/changeset/203350)
13. `Mutex` and `RwLock` support [eventual fairness](https://trac.webkit.org/changeset/203350)
which allows them to be fair on average without sacrificing performance.
15. A `ReentrantMutex` type which supports recursive locking.
16. An *experimental* deadlock detector that works for `Mutex`,
14. A `ReentrantMutex` type which supports recursive locking.
15. An *experimental* deadlock detector that works for `Mutex`,
`RwLock` and `ReentrantMutex`. This feature is disabled by default and
can be enabled via the `deadlock_detection` feature.
17. `RwLock` supports atomically upgrading an "upgradable" read lock into a
16. `RwLock` supports atomically upgrading an "upgradable" read lock into a
write lock.
18. Optional support for [serde](https://docs.serde.rs/serde/). Enable via the
17. Optional support for [serde](https://docs.serde.rs/serde/). Enable via the
feature `serde`. **NOTE!** this support is for `Mutex`, `ReentrantMutex`,
and `RwLock` only; `Condvar` and `Once` are not currently supported.
19. Lock guards can be sent to other threads when the `send_guard` feature is
18. Lock guards can be sent to other threads when the `send_guard` feature is
enabled.

## The parking lot
Expand Down

0 comments on commit 70c4e57

Please sign in to comment.