Alacritty/winit event loop stalls and delays keyboard events

[awused]

Since upgrading to Fedora 40 and Alacritty 0.13.2 I've been dealing with frequent keyboard stalls, where I will type characters but nothing will happen, but only in Alacritty. They can be several seconds long and, though I didn't time it, I think I've had one or two over ten seconds long.

Mouse events are not affected, and if I'm quick I'm able to scroll windows that are experiencing keyboard stalls with the mouse wheel while they remain stuck. They happen regardless of the application running in the terminal. Having activity in other terminals (cat /dev/random) seems to cause them much more frequently.

System

OS: Fedora 40
Version: alacritty 0.13.2

Linux/BSD: x11, i3, picom at first but then no compositor (did not make a difference)

Logs

Keyboard and bindings:

I caught a few of the stalls, but this one is definitely the cleanest:

[118.792198856s] [INFO ] [alacritty] winit event: AboutToWait
[118.796161403s] [INFO ] [alacritty] winit event: NewEvents(WaitCancelled { start: Instant { tv_sec: 10512, tv_nsec: 3108315 }, requested_resume: None })
[118.796180619s] [INFO ] [alacritty] winit event: WindowEvent { window_id: WindowId(WindowId(6291461)), event: CursorLeft { device_id: DeviceId(X(DeviceId(2))) } }
[118.796191389s] [INFO ] [alacritty] winit event: AboutToWait
[118.805209435s] [INFO ] [alacritty] winit event: NewEvents(WaitCancelled { start: Instant { tv_sec: 10512, tv_nsec: 7098463 }, requested_resume: None })
[118.805236506s] [INFO ] [alacritty] winit event: AboutToWait
[118.869164706s] [INFO ] [alacritty] winit event: NewEvents(WaitCancelled { start: Instant { tv_sec: 10512, tv_nsec: 16145212 }, requested_resume: None })
[118.869183922s] [INFO ] [alacritty] winit event: AboutToWait
[118.885150626s] [INFO ] [alacritty] winit event: NewEvents(WaitCancelled { start: Instant { tv_sec: 10512, tv_nsec: 80089914 }, requested_resume: None })
[118.885171204s] [INFO ] [alacritty] winit event: AboutToWait
[119.125184420s] [INFO ] [alacritty] winit event: NewEvents(WaitCancelled { start: Instant { tv_sec: 10512, tv_nsec: 96077116 }, requested_resume: None })
[119.125207593s] [INFO ] [alacritty] winit event: AboutToWait
[119.205177047s] [INFO ] [alacritty] winit event: NewEvents(WaitCancelled { start: Instant { tv_sec: 10512, tv_nsec: 336114797 }, requested_resume: None })
[119.205195772s] [INFO ] [alacritty] winit event: AboutToWait
[119.325185499s] [INFO ] [alacritty] winit event: NewEvents(WaitCancelled { start: Instant { tv_sec: 10512, tv_nsec: 416101753 }, requested_resume: None })
[119.325212088s] [INFO ] [alacritty] winit event: AboutToWait
[122.029282210s] [INFO ] [alacritty] winit event: NewEvents(WaitCancelled { start: Instant { tv_sec: 10512, tv_nsec: 536120024 }, requested_resume: None })
[122.029337544s] [INFO ] [alacritty] winit event: AboutToWait
[122.157192181s] [INFO ] [alacritty] winit event: NewEvents(WaitCancelled { start: Instant { tv_sec: 10515, tv_nsec: 240246010 }, requested_resume: None })
[122.157219441s] [INFO ] [alacritty] winit event: AboutToWait
[123.456324058s] [INFO ] [alacritty] winit event: NewEvents(WaitCancelled { start: Instant { tv_sec: 10515, tv_nsec: 368126485 }, requested_resume: None })
[123.456398297s] [INFO ] [alacritty] winit event: WindowEvent { window_id: WindowId(WindowId(6291461)), event: KeyboardInput { device_id: DeviceId(X(DeviceId(3))), event: KeyEvent { physical_key: Code(KeyD), logical_key: Character("d"), text: Some("d"), location: Standard, state: Released, repeat: false, platform_specific: KeyEventExtra { key_without_modifiers: Character("d"), text_with_all_modifiers: Some("d") } }, is_synthetic: false } }
[123.456425217s] [INFO ] [alacritty] winit event: AboutToWait
[123.457810507s] [INFO ] [alacritty] winit event: NewEvents(WaitCancelled { start: Instant { tv_sec: 10516, tv_nsec: 667340206 }, requested_resume: None })
[123.457852385s] [INFO ] [alacritty] winit event: WindowEvent { window_id: WindowId(WindowId(6291461)), event: KeyboardInput { device_id: DeviceId(X(DeviceId(3))), event: KeyEvent { physical_key: Code(KeyS), logical_key: Character("s"), text: Some("s"), location: Standard, state: Pressed, repeat: false, platform_specific: KeyEventExtra { key_without_modifiers: Character("s"), text_with_all_modifiers: Some("s") } }, is_synthetic: false } }
[123.457869056s] [INFO ] [alacritty] winit event: AboutToWait
[123.458543226s] [INFO ] [alacritty] winit event: NewEvents(WaitCancelled { start: Instant { tv_sec: 10516, tv_nsec: 668787411 }, requested_resume: None })
[123.458571659s] [INFO ] [alacritty] winit event: WindowEvent { window_id: WindowId(WindowId(6291461)), event: KeyboardInput { device_id: DeviceId(X(DeviceId(3))), event: KeyEvent { physical_key: Code(KeyA), logical_key: Character("a"), text: Some("a"), location: Standard, state: Pressed, repeat: false, platform_specific: KeyEventExtra { key_without_modifiers: Character("a"), text_with_all_modifiers: Some("a") } }, is_synthetic: false } }
[123.458580245s] [INFO ] [alacritty] winit event: AboutToWait
[123.459007674s] [INFO ] [alacritty] winit event: NewEvents(WaitCancelled { start: Instant { tv_sec: 10516, tv_nsec: 669489633 }, requested_resume: None })
[123.459036468s] [INFO ] [alacritty] winit event: WindowEvent { window_id: WindowId(WindowId(6291461)), event: KeyboardInput { device_id: DeviceId(X(DeviceId(3))), event: KeyEvent { physical_key: Code(KeyD), logical_key: Character("d"), text: Some("d"), location: Standard, state: Pressed, repeat: false, platform_specific: KeyEventExtra { key_without_modifiers: Character("d"), text_with_all_modifiers: Some("d") } }, is_synthetic: false } }
[123.459044874s] [INFO ] [alacritty] winit event: AboutToWait
[123.459425345s] [INFO ] [alacritty] winit event: NewEvents(WaitCancelled { start: Instant { tv_sec: 10516, tv_nsec: 669953701 }, requested_resume: None })
[123.459451424s] [INFO ] [alacritty] winit event: WindowEvent { window_id: WindowId(WindowId(6291461)), event: KeyboardInput { device_id: DeviceId(X(DeviceId(3))), event: KeyEvent { physical_key: Code(KeyF), logical_key: Character("f"), text: Some("f"), location: Standard, state: Released, repeat: false, platform_specific: KeyEventExtra { key_without_modifiers: Character("f"), text_with_all_modifiers: Some("f") } }, is_synthetic: false } }
[123.459459699s] [INFO ] [alacritty] winit event: AboutToWait
[123.459868814s] [INFO ] [alacritty] winit event: NewEvents(WaitCancelled { start: Instant { tv_sec: 10516, tv_nsec: 670365070 }, requested_resume: None })
[123.459894452s] [INFO ] [alacritty] winit event: WindowEvent { window_id: WindowId(WindowId(6291461)), event: KeyboardInput { device_id: DeviceId(X(DeviceId(3))), event: KeyEvent { physical_key: Code(KeyF), logical_key: Character("f"), text: Some("f"), location: Standard, state: Pressed, repeat: false, platform_specific: KeyEventExtra { key_without_modifiers: Character("f"), text_with_all_modifiers: Some("f") } }, is_synthetic: false } }
[123.459902457s] [INFO ] [alacritty] winit event: AboutToWait
[123.460317522s] [INFO ] [alacritty] winit event: NewEvents(WaitCancelled { start: Instant { tv_sec: 10516, tv_nsec: 670810913 }, requested_resume: None })
[123.460342058s] [INFO ] [alacritty] winit event: WindowEvent { window_id: WindowId(WindowId(6291461)), event: KeyboardInput { device_id: DeviceId(X(DeviceId(3))), event: KeyEvent { physical_key: Code(KeyA), logical_key: Character("a"), text: Some("a"), location: Standard, state: Released, repeat: false, platform_specific: KeyEventExtra { key_without_modifiers: Character("a"), text_with_all_modifiers: Some("a") } }, is_synthetic: false } }
[123.460350214s] [INFO ] [alacritty] winit event: AboutToWait
[123.460716839s] [INFO ] [alacritty] winit event: NewEvents(WaitCancelled { start: Instant { tv_sec: 10516, tv_nsec: 671255544 }, requested_resume: None })
[123.460743198s] [INFO ] [alacritty] winit event: WindowEvent { window_id: WindowId(WindowId(6291461)), event: KeyboardInput { device_id: DeviceId(X(DeviceId(3))), event: KeyEvent { physical_key: Code(KeyS), logical_key: Character("s"), text: Some("s"), location: Standard, state: Released, repeat: false, platform_specific: KeyEventExtra { key_without_modifiers: Character("s"), text_with_all_modifiers: Some("s") } }, is_synthetic: false } }
[123.460751253s] [INFO ] [alacritty] winit event: AboutToWait
[123.460764177s] [INFO ] [alacritty] winit event: NewEvents(WaitCancelled { start: Instant { tv_sec: 10516, tv_nsec: 671658878 }, requested_resume: None })
[123.460770760s] [INFO ] [alacritty] winit event: UserEvent(Event { window_id: Some(WindowId(WindowId(6291461))), payload: Terminal(Wakeup) })
[123.460778013s] [INFO ] [alacritty] winit event: WindowEvent { window_id: WindowId(WindowId(6291461)), event: RedrawRequested }
[123.461128108s] [INFO ] [alacritty] winit event: AboutToWait
[123.461142665s] [INFO ] [alacritty] winit event: NewEvents(WaitCancelled { start: Instant { tv_sec: 10516, tv_nsec: 672037135 }, requested_resume: None })
[123.461264442s] [INFO ] [alacritty] winit event: WindowEvent { window_id: WindowId(WindowId(6291461)), event: KeyboardInput { device_id: DeviceId(X(DeviceId(3))), event: KeyEvent { physical_key: Code(KeyD), logical_key: Character("d"), text: Some("d"), location: Standard, state: Released, repeat: false, platform_specific: KeyEventExtra { key_without_modifiers: Character("d"), text_with_all_modifiers: Some("d") } }, is_synthetic: false } }
[123.461272998s] [INFO ] [alacritty] winit event: UserEvent(Event { window_id: Some(WindowId(WindowId(6291461))), payload: Terminal(Wakeup) })
[123.461278128s] [INFO ] [alacritty] winit event: UserEvent(Event { window_id: Some(WindowId(WindowId(6291461))), payload: Frame })
[123.461283388s] [INFO ] [alacritty] winit event: WindowEvent { window_id: WindowId(WindowId(6291461)), event: RedrawRequested }
[123.461561498s] [INFO ] [alacritty] winit event: AboutToWait
[123.461572488s] [INFO ] [alacritty] winit event: NewEvents(WaitCancelled { start: Instant { tv_sec: 10516, tv_nsec: 672468201 }, requested_resume: Some(Instant { tv_sec: 10516, tv_nsec: 679662769 }) })
[123.461579371s] [INFO ] [alacritty] winit event: UserEvent(Event { window_id: Some(WindowId(WindowId(6291461))), payload: Terminal(Wakeup) })
[123.461584010s] [INFO ] [alacritty] winit event: AboutToWait
[123.461653690s] [INFO ] [alacritty] winit event: NewEvents(WaitCancelled { start: Instant { tv_sec: 10516, tv_nsec: 672489160 }, requested_resume: Some(Instant { tv_sec: 10516, tv_nsec: 679662769 }) })
[123.461765419s] [INFO ] [alacritty] winit event: WindowEvent { window_id: WindowId(WindowId(6291461)), event: KeyboardInput { device_id: DeviceId(X(DeviceId(3))), event: KeyEvent { physical_key: Code(KeyF), logical_key: Character("f"), text: Some("f"), location: Standard, state: Released, repeat: false, platform_specific: KeyEventExtra { key_without_modifiers: Character("f"), text_with_all_modifiers: Some("f") } }, is_synthetic: false } }
[123.461773905s] [INFO ] [alacritty] winit event: AboutToWait
[123.462166428s] [INFO ] [alacritty] winit event: NewEvents(WaitCancelled { start: Instant { tv_sec: 10516, tv_nsec: 672679846 }, requested_resume: Some(Instant { tv_sec: 10516, tv_nsec: 679662769 }) })
[123.462187047s] [INFO ] [alacritty] winit event: WindowEvent { window_id: WindowId(WindowId(6291461)), event: KeyboardInput { device_id: DeviceId(X(DeviceId(3))), event: KeyEvent { physical_key: Code(KeyF), logical_key: Character("f"), text: Some("f"), location: Standard, state: Pressed, repeat: false, platform_specific: KeyEventExtra { key_without_modifiers: Character("f"), text_with_all_modifiers: Some("f") } }, is_synthetic: false } }
[123.462193529s] [INFO ] [alacritty] winit event: AboutToWait
[123.462527052s] [INFO ] [alacritty] winit event: NewEvents(WaitCancelled { start: Instant { tv_sec: 10516, tv_nsec: 673101374 }, requested_resume: Some(Instant { tv_sec: 10516, tv_nsec: 679662769 }) })
[123.462549063s] [INFO ] [alacritty] winit event: WindowEvent { window_id: WindowId(WindowId(6291461)), event: KeyboardInput { device_id: DeviceId(X(DeviceId(3))), event: KeyEvent { physical_key: Code(KeyF), logical_key: Character("f"), text: Some("f"), location: Standard, state: Released, repeat: false, platform_specific: KeyEventExtra { key_without_modifiers: Character("f"), text_with_all_modifiers: Some("f") } }, is_synthetic: false } }
[123.462555496s] [INFO ] [alacritty] winit event: AboutToWait
[123.462893397s] [INFO ] [alacritty] winit event: NewEvents(WaitCancelled { start: Instant { tv_sec: 10516, tv_nsec: 673460035 }, requested_resume: Some(Instant { tv_sec: 10516, tv_nsec: 679662769 }) })
[123.462916941s] [INFO ] [alacritty] winit event: WindowEvent { window_id: WindowId(WindowId(6291461)), event: KeyboardInput { device_id: DeviceId(X(DeviceId(3))), event: KeyEvent { physical_key: Code(KeyF), logical_key: Character("f"), text: Some("f"), location: Standard, state: Pressed, repeat: false, platform_specific: KeyEventExtra { key_without_modifiers: Character("f"), text_with_all_modifiers: Some("f") } }, is_synthetic: false } }
[123.462923443s] [INFO ] [alacritty] winit event: AboutToWait
[123.463286512s] [INFO ] [alacritty] winit event: NewEvents(WaitCancelled { start: Instant { tv_sec: 10516, tv_nsec: 673830757 }, requested_resume: Some(Instant { tv_sec: 10516, tv_nsec: 679662769 }) })
[123.463313142s] [INFO ] [alacritty] winit event: WindowEvent { window_id: WindowId(WindowId(6291461)), event: KeyboardInput { device_id: DeviceId(X(DeviceId(3))), event: KeyEvent { physical_key: Code(KeyF), logical_key: Character("f"), text: Some("f"), location: Standard, state: Released, repeat: false, platform_specific: KeyEventExtra { key_without_modifiers: Character("f"), text_with_all_modifiers: Some("f") } }, is_synthetic: false } }

I was tapping the f key at a fairly consistent pace. Almost every single one of those WaitCancelled events was a physical key press on my keyboard, but the characters were not visible for nearly 5 seconds and then a backlog of characters all came at once in a very short burst.

[kchibisov]

Do you have any input method running or other input software? It just sounds like IME issue or something.

[awused]

Disabling my IME (ibus) seems to have fixed it, at least no stalls in the last ~20 minutes, which is probably good enough given how common they were. Though no other applications (including other terminals, but I have nothing else using winit) have been affected. I've been using my IME unchanged for nearly a decade now, and it wasn't updated in the system upgrade, so I'm not actually confident that it's the root of the issue.