High CPU usage when Windows Screens Sleep

[tanj]

When my windows system sets the screen to sleep the alacratty process ramps up CPU usage which then stops when the screen is woken. This may have the same source as this firefox bug https://bugzilla.mozilla.org/show_bug.cgi?id=1924932

If I close alacritty and then lock the screen and wait for the screen to sleep then I get a nice quite cpu. If I leave alacritty running and lock the screen and wait for the screen to sleep then the CPU fan ramps up as soon as the screens sleep. Perfmon trace shows alacritty is being a problem here.

I have found three apps that seem to be affected by what ever the root cause of this is. The three apps are:

• alacritty
• littlebigmouse
• firefox

When testing this firefox and littlebigmouse were not running.

System

OS: Windows 11 Pro (10.0.26100 Build 26100) [24H2]
Version: alacritty --version : alacritty 0.14.0

Logs

perfmon screenshot. Screens go to sleep at 10:45:11 and dwm (purple) and alacritty (teal) ramp up

[chrisduerr]

You're saying three apps are affected by this, but your screenshot suggests that dwm has the same issue, is that correct?

Could you try getting the examples of https://github.com/rust-windowing/glutin to work? I suspect these should show the same problem.

[kchibisov]

it just looks like busy drawing loop.

[tanj]

dwm is window's desktop window manager. It spikes because of the offending programs.

When I run the example: cargo run --example window in glutin The process runs at the same level whether the screen is asleep or not, but does cause dwm to increase processor usage when the monitors go to sleep.