Bevy 0.10 regression: very long startup if `WinitSettings.unfocused_mode` is set to `UpdateMode::Reactive`

[JayceFayne]

Bevy version

The release number or commit hash of the version you're using.

0.10/0.11/0.12/0.13

Relevant system information

Arch Linux

What you did

Running https://github.com/JayceFayne/bevy_regression
Pasting main.rs below:

use bevy::prelude::*;
use bevy::winit::WinitSettings;

fn main() {
    App::new()
        .insert_resource(WinitSettings::desktop_app())
        .add_plugins(DefaultPlugins.build())
        .run();
}

What went wrong

Takes very long to start

Additional information

Downgrading to 0.9 fixes the issue

[alice-i-cecile]

Could you give us a before / after tracing flamegraph? This might be due to the more involved system graph processing.

If that's the case, there are a number of things we can do to improve performance there, ranging from simple optimizations to caching the graph on disk.

See https://github.com/bevyengine/bevy/blob/main/docs/profiling.md for more info.

[alice-i-cecile]

Alternatively, given your reproduction this could just be a bug with how we / winit is handling that specific mode.

[JayceFayne]

Could you give us a before / after tracing flamegraph? This might be due to the more involved system graph processing.

If that's the case, there are a number of things we can do to improve performance there, ranging from simple optimizations to caching the graph on disk.

See https://github.com/bevyengine/bevy/blob/main/docs/profiling.md for more info.

Sure, I have traces for 0.9 and 0.10 in chrome tracing format, I'll attach them here. Since github does not allow me to upload json files I'll upload the rendered flamegraph.

My guess is that the 60 sec wait in 0.10 is because max_wait is set to 60 secs in unfocused mode for the desktop_app preset.