Is it normal that bevy use much CPU resource for simple programs ?

[newDINO]

I tried running bevy 0.17.3 on an old device. And a simple example like a button ui or 2d shapes consumes around 40~50% of a single core (shown in top on linux), while an equivalent wgpu+winit program only uses around 5% when the frame rate is capped (100% using unlimited frame rate).

Both built using -O3 on debug built with no debug info for faster build and smaller binary size.

[hymm]

bevy is by default multithreaded, so it's probably that. You could try removing the multithreaded feature or change all the schedules to single threaded if you're worried about cpu usage.

[newDINO]

I tried disabling multi_threaded , now the CPU usage is down to around 20~25%, basically halved.

[newDINO]

I also tried putting the main render logic of the equivalent wgpu+winit program into a rayon thread pool (but there is nothing to be parallelized as it is basically a sequential logic), the CPU consumption is increased by around 0.4%. It seems using threads do have a non-trivial impact on CPU consumption, especially considering bevy may have many more tasks running in parallel.