1.28.0 (April 25th, 2023)

Added

• io: add AsyncFd::async_io (#5542)
• io: impl BufMut for ReadBuf (#5590)
• net: add recv_buf for UdpSocket and UnixDatagram (#5583)
• sync: add OwnedSemaphorePermit::semaphore (#5618)
• sync: add same_channel to broadcast channel (#5607)
• sync: add watch::Receiver::wait_for (#5611)
• task: add JoinSet::spawn_blocking and JoinSet::spawn_blocking_on (#5612)

Changed

• deps: update windows-sys to 0.48 (#5591)
• io: make read_to_end not grow unnecessarily (#5610)
• macros: make entrypoints more efficient (#5621)
• sync: improve Debug impl for RwLock (#5647)
• sync: reduce contention in Notify (#5503)

Fixed

• net: support get_peer_cred on AIX (#5065)
• sync: avoid deadlocks in broadcast with custom wakers (#5578)

Documented

• sync: fix typo in Semaphore::MAX_PERMITS (#5645)
• sync: fix typo in tokio::sync::watch::Sender docs (#5587)

1.27.0 (March 27th, 2023)

This release bumps the MSRV of Tokio to 1.56. (#5559)

Added

• io: add async_io helper method to sockets (#5512)
• io: add implementations of AsFd/AsHandle/AsSocket (#5514, #5540)
• net: add UdpSocket::peek_sender() (#5520)
• sync: add RwLockWriteGuard::{downgrade_map, try_downgrade_map} (#5527)
• task: add JoinHandle::abort_handle (#5543)

Changed

• io: use memchr from libc (#5558)
• macros: accept path as crate rename in #[tokio::main] (#5557)
• macros: update to syn 2.0.0 (#5572)
• time: don't register for a wakeup when Interval returns Ready (#5553)

Fixed

• fs: fuse std iterator in ReadDir (#5555)
• tracing: fix spawn_blocking location fields (#5573)
• time: clean up redundant check in Wheel::poll() (#5574)

Documented

• macros: define cancellation safety (#5525)
• io: add details to docs of tokio::io::copy[_buf] (#5575)
• io: refer to ReaderStream and StreamReader in module docs (#5576)

Fixed

• macros: fix empty join! and try_join! (https://github.com/tokio-rs/tokio/pull/5504)
• sync: don't leak tracing spans in mutex guards (https://github.com/tokio-rs/tokio/pull/5469)
• sync: drop wakers after unlocking the mutex in Notify (https://github.com/tokio-rs/tokio/pull/5471)
• sync: drop wakers outside lock in semaphore (https://github.com/tokio-rs/tokio/pull/5475)

Added

• fs: add fs::try_exists (https://github.com/tokio-rs/tokio/pull/4299)
• net: add types for named unix pipes (https://github.com/tokio-rs/tokio/pull/5351)
• sync: add MappedOwnedMutexGuard (https://github.com/tokio-rs/tokio/pull/5474)

Changed

• chore: update windows-sys to 0.45 (https://github.com/tokio-rs/tokio/pull/5386)
• net: use Message Read Mode for named pipes (https://github.com/tokio-rs/tokio/pull/5350)
• sync: mark lock guards with #[clippy::has_significant_drop] (https://github.com/tokio-rs/tokio/pull/5422)
• sync: reduce contention in watch channel (https://github.com/tokio-rs/tokio/pull/5464)
• time: remove cache padding in timer entries (https://github.com/tokio-rs/tokio/pull/5468)
• time: Improve Instant::now() perf with test-util (https://github.com/tokio-rs/tokio/pull/5513)

Internal Changes

• io: use poll_fn in copy_bidirectional (https://github.com/tokio-rs/tokio/pull/5486)
• net: refactor named pipe builders to not use bitfields (https://github.com/tokio-rs/tokio/pull/5477)
• rt: remove Arc from Clock (https://github.com/tokio-rs/tokio/pull/5434)
• sync: make notify_waiters calls atomic (https://github.com/tokio-rs/tokio/pull/5458)
• time: don't store deadline twice in sleep entries (https://github.com/tokio-rs/tokio/pull/5410)

Unstable

• metrics: add a new metric for budget exhaustion yields (https://github.com/tokio-rs/tokio/pull/5517)

Documented

• io: improve AsyncFd example (https://github.com/tokio-rs/tokio/pull/5481)
• runtime: document the nature of the main future (https://github.com/tokio-rs/tokio/pull/5494)
• runtime: remove extra period in docs (https://github.com/tokio-rs/tokio/pull/5511)
• signal: updated Documentation for Signals (https://github.com/tokio-rs/tokio/pull/5459)
• sync: add doc aliases for blocking_* methods (https://github.com/tokio-rs/tokio/pull/5448)
• sync: fix docs for Send/Sync bounds in broadcast (https://github.com/tokio-rs/tokio/pull/5480)
• sync: document drop behavior for channels (https://github.com/tokio-rs/tokio/pull/5497)
• task: clarify what happens to spawned work during runtime shutdown (https://github.com/tokio-rs/tokio/pull/5394)
• task: clarify process::Command docs (https://github.com/tokio-rs/tokio/pull/5413)
• task: fix wording with 'unsend' (https://github.com/tokio-rs/tokio/pull/5452)
• time: document immediate completion guarantee for timeouts (https://github.com/tokio-rs/tokio/pull/5509)
• tokio: document supported platforms (https://github.com/tokio-rs/tokio/pull/5483)

1.25.0 (January 28, 2023)

Fixed

• rt: fix runtime metrics reporting (#5330)

Added

• sync: add broadcast::Sender::len (#5343)

Changed

• fs: increase maximum read buffer size to 2MiB (#5397)

This release fixes a compilation failure on targets without AtomicU64 when using rustc older than 1.63. (#5356)

The highlight of this release is the reduction of lock contention for all I/O operations (#5300). We have received reports of up to a 20% improvement in CPU utilization and increased throughput for real-world I/O heavy applications.

Fixed

• rt: improve native AtomicU64 support detection (#5284)

Added

• rt: add configuration option for max number of I/O events polled from the OS per tick (#5186)
• rt: add an environment variable for configuring the default number of worker threads per runtime instance (#4250)

Changed

• sync: reduce MPSC channel stack usage (#5294)
• io: reduce lock contention in I/O operations (#5300)
• fs: speed up read_dir() by chunking operations (#5309)
• rt: use internal ThreadId implementation (#5329)
• test: don't auto-advance time when a spawn_blocking task is running (#5115)

This release forward ports changes from 1.18.4.

Fixed

• net: fix Windows named pipe server builder to maintain option when toggling pipe mode (#5336).

Fixed

• net: fix Windows named pipe connect (#5208)
• io: support vectored writes for ChildStdin (#5216)
• io: fix async fn ready() false positive for OS-specific events (#5231)

Changed

• runtime: yield_now defers task until after driver poll (#5223)
• runtime: reduce amount of codegen needed per spawned task (#5213)
• windows: replace winapi dependency with windows-sys (#5204)

Added

• runtime: add Handle::runtime_flavor (#5138)
• sync: add Mutex::blocking_lock_owned (#5130)
• sync: add Semaphore::MAX_PERMITS (#5144)
• sync: add merge() to semaphore permits (#4948)
• sync: add mpsc::WeakUnboundedSender (#5189)

Added (unstable)

• process: add Command::process_group (#5114)
• runtime: export metrics about the blocking thread pool (#5161)
• task: add task::id() and task::try_id() (#5171)

Fixed

• macros: don't take ownership of futures in macros (#5087)
• runtime: fix Stacked Borrows violation in LocalOwnedTasks (#5099)
• runtime: mitigate ABA with 32-bit queue indices when possible (#5042)
• task: wake local tasks to the local queue when woken by the same thread (#5095)
• time: panic in release mode when mark_pending called illegally (#5093)
• runtime: fix typo in expect message (#5169)
• runtime: fix unsync_load on atomic types (#5175)
• task: elaborate safety comments in task deallocation (#5172)
• runtime: fix LocalSet drop in thread local (#5179)
• net: remove libc type leakage in a public API (#5191)
• runtime: update the alignment of CachePadded (#5106)

Changed

• io: make tokio::io::copy continue filling the buffer when writer stalls (#5066)
• runtime: remove coop::budget from LocalSet::run_until (#5155)
• sync: make Notify panic safe (#5154)

Documented

• io: fix doc for write_i8 to use signed integers (#5040)
• net: fix doc typos for TCP and UDP set_tos methods (#5073)
• net: fix function name in UdpSocket::recv documentation (#5150)
• sync: typo in TryLockError for RwLock::try_write (#5160)
• task: document that spawned tasks execute immediately (#5117)
• time: document return type of timeout (#5118)
• time: document that timeout checks only before poll (#5126)
• sync: specify return type of oneshot::Receiver in docs (#5198)

Internal changes

• runtime: use const Mutex::new for globals (#5061)
• runtime: remove Option around mio::Events in io driver (#5078)
• runtime: remove a conditional compilation clause (#5104)
• runtime: remove a reference to internal time handle (#5107)
• runtime: misc time driver cleanup (#5120)
• runtime: move signal driver to runtime module (#5121)
• runtime: signal driver now uses I/O driver directly (#5125)
• runtime: start decoupling I/O driver and I/O handle (#5127)
• runtime: switch io::handle refs with scheduler:Handle (#5128)
• runtime: remove Arc from I/O driver (#5134)
• runtime: use signal driver handle via scheduler::Handle (#5135)
• runtime: move internal clock fns out of context (#5139)
• runtime: remove runtime::context module (#5140)
• runtime: keep driver cfgs in driver.rs (#5141)
• runtime: add runtime::context to unify thread-locals (#5143)
• runtime: rename some confusing internal variables/fns (#5151)
• runtime: move coop mod into runtime (#5152)
• runtime: move budget state to context thread-local (#5157)
• runtime: move park logic into runtime module (#5158)
• runtime: move Runtime into its own file (#5159)
• runtime: unify entering a runtime with Handle::enter (#5163)
• runtime: remove handle reference from each scheduler (#5166)
• runtime: move enter into context (#5167)
• runtime: combine context and entered thread-locals (#5168)
• runtime: fix accidental unsetting of current handle (#5178)
• runtime: move CoreStage methods to Core (#5182)
• sync: name mpsc semaphore types (#5146)

1.21.2 (September 27, 2022)

This release removes the dependency on the once_cell crate to restore the MSRV of 1.21.x, which is the latest minor version at the time of release. (#5048)