Very high CPU usage on mouse movement

[vladh]

Is your issue REALLY a bug?

• My issue is indeed a bug!
• I am not crazy! I will not fill out this form just to ask a question or request a feature. Pinky promise.

Is there an existing issue for this?

• I have searched the existing issues.

Is this issue related to iced?

• My hardware is compatible and my graphics drivers are up-to-date.

What happened?

I'm seeing very high CPU usage (10–25%) and long render times (4–6ms) when moving my mouse. This might not be related to the mouse specifically, but it might appear when any events happen. The layout stage is also taking longer than I would expect.

This happens both in debug and release mode, both on Wayland and X11. In debug mode, render times are around 5x longer, which might be expected. I'm running sway 1.9 with the radv driver.

I've done some testing with RenderDoc but it does not seem to be a GPU-bound issue, since RenderDoc is showing GPU times of 0.0005ms per frame.

I do not have this problem with wgpu/examples/src/hello_triangle, or with winit/examples/window.rs.

Very happy to help debugging this further, but ideas would be appreciated.

Potentially related to #2477 and #2459, but unclear.

Not related to #2558.

In iced/examples/tour:

Profile: https://share.firefox.dev/4gCBgt8

In iced/examples/geometry:

Profile: https://share.firefox.dev/3ZM1V0C

What is the expected behavior?

I expect < 1% CPU usage, and < 2–3ms render times for simple examples.

Version

master

Operating System

Linux

Do you have any log output?

No response