Debug breakpoint make High GPU

[diiyw]

Ebitengine Version

2.8.1

Operating System

• Windows
• macOS
• Linux
• FreeBSD
• OpenBSD
• Android
• iOS
• Nintendo Switch
• PlayStation 5
• Xbox
• Web Browsers

Go Version (go version)

go version go1.22.5 windows/amd64

What steps will reproduce the problem?

My GPU: RTX 3060
Test code:

package main

import (
	"github.com/hajimehoshi/ebiten/v2"
	"image/color"
)

type game struct {
}

func (g *game) Update() error {
	return nil
}

func (g *game) Draw(screen *ebiten.Image) {
	for i := 0; i < 1000; i++ {  // breakpoint here
		screen.Fill(color.White)
	}
}

func (g *game) Layout(outsideWidth, outsideHeight int) (int, int) {
	return outsideWidth, outsideHeight
}

func main() {
	ebiten.SetTPS(60)
	ebiten.SetVsyncEnabled(true)
	ebiten.SetWindowSize(800, 600)
	ebiten.MaximizeWindow()
	ebiten.RunGame(&game{})
}

Add beakpoint here.

When the program first breaks, remove this breakpoint, let Ebiten continue running, and you will observe the high GPU usage.

What is the expected result?

GPU less 1%

What happens instead?

Very very high GPU usage

Anything else you feel useful to add?

No response

[hajimehoshi]

This doesn't sound like a real world issue, so I perhaps don't fix this.

[hajimehoshi]

When the program first breaks, remove this breakpoint, let Ebiten continue running, and you will observe the high GPU usage.

Oh, does this happen when you added a breakpoint?

[diiyw]

Yes, I added this breakpoint before launching, and when I start the game in Debug mode, the breakpoint is effective. At this point, if I remove the breakpoint, Ebiten runs normally, but it uses a very high amount of GPU.

[hajimehoshi]

What about using OpenGL?

op := &ebiten.RunGameOptions{
    GraphicsLibrary: ebiten.GraphicsLibraryOpenGL,
}
ebiten.RunGame(&game{}, op)

[diiyw]

What about using OpenGL?

op := &ebiten.RunGameOptions{
    GraphicsLibrary: ebiten.GraphicsLibraryOpenGL,
}
ebiten.RunGame(&game{}, op)

Using OpenGL seems to be running normally, with an 8% GPU usage. I noticed that with the default settings, when I hit a breakpoint and then resume for the first time, the window displays but is not active. When I pause the program a second time and disable the breakpoint, it no longer runs in the foreground and consumes a high amount of GPU resources. Once I bring it back to the foreground, the GPU usage gradually returns to a normal 0.5% after a short wait.