Heavy CPU Utilization w/o Game Logic

[APDevice]

So I just started using Ebiten recently. So far I have only got the rendering done for the game I'm working on, and yet I'm already seeing my CPU utilization for my runtime spike to 100%. There doesn't seem to be anything in my code that should be causing this.

System: MacBook Pro 2016 running Big Sur
Source: https://github.com/APDevice/goCheckers

[hajimehoshi]

Thank you for using Ebiten.

From the code, I couldn't find suspicious things. Would it be possible to take a CPU profile around the spike?

For a relatively static application, we plan to add a new feature #1556

[APDevice]

Thanks. How did you take this profile? I wanted to know the result of pprof with e.g., github.com/pkg/profile.

I used the task profiler built into the Mac OS Activity Monitor.

Here are the results of pprof:

Type: cpu
Time: May 5, 2021 at 10:00pm (PDT)
Duration: 6.23s, Total samples = 6.21s (99.75%)
Showing nodes accounting for 6.08s, 97.91% of 6.21s total
Dropped 48 nodes (cum <= 0.03s)
      flat  flat%   sum%        cum   cum%
     4.66s 75.04% 75.04%      4.66s 75.04%  runtime.cgocall
     0.54s  8.70% 83.74%      0.54s  8.70%  runtime.pthread_cond_wait
     0.27s  4.35% 88.08%      0.27s  4.35%  runtime.nanotime1
     0.27s  4.35% 92.43%      0.27s  4.35%  runtime.pthread_cond_signal
     0.18s  2.90% 95.33%      0.18s  2.90%  <unknown>
     0.09s  1.45% 96.78%      0.09s  1.45%  runtime.memhash64
     0.04s  0.64% 97.42%      0.04s  0.64%  runtime.pthread_mutex_unlock
     0.02s  0.32% 97.75%      0.51s  8.21%  runtime.findrunnable
     0.01s  0.16% 97.91%      0.04s  0.64%  github.com/hajimehoshi/ebiten/v2.(*uiContext).Update
         0     0% 97.91%      4.48s 72.14%  github.com/go-gl/glfw/v3.3/glfw.Joystick.GetButtons
         0     0% 97.91%      0.10s  1.61%  github.com/go-gl/glfw/v3.3/glfw.PollEvents
         0     0% 97.91%      4.48s 72.14%  github.com/go-gl/glfw/v3.3/glfw._Cfunc_glfwGetJoystickButtons
         0     0% 97.91%      0.10s  1.61%  github.com/go-gl/glfw/v3.3/glfw._Cfunc_glfwPollEvents
         0     0% 97.91%      4.78s 76.97%  github.com/hajimehoshi/ebiten/v2.RunGame
         0     0% 97.91%      4.78s 76.97%  github.com/hajimehoshi/ebiten/v2.runGame
         0     0% 97.91%      4.48s 72.14%  github.com/hajimehoshi/ebiten/v2/internal/glfw.Joystick.GetButtons
         0     0% 97.91%      0.10s  1.61%  github.com/hajimehoshi/ebiten/v2/internal/glfw.PollEvents (inline)
         0     0% 97.91%      0.05s  0.81%  github.com/hajimehoshi/ebiten/v2/internal/graphicsdriver/metal.(*Graphics).SetVertices.func1
         0     0% 97.91%      0.04s  0.64%  github.com/hajimehoshi/ebiten/v2/internal/graphicsdriver/metal/mtl.Device.MakeBufferWithBytes
         0     0% 97.91%      0.04s  0.64%  github.com/hajimehoshi/ebiten/v2/internal/graphicsdriver/metal/mtl.Device.MakeBufferWithBytes.func1
         0     0% 97.91%      0.04s  0.64%  github.com/hajimehoshi/ebiten/v2/internal/graphicsdriver/metal/mtl._Cfunc_Device_MakeBufferWithBytes
         0     0% 97.91%      4.78s 76.97%  github.com/hajimehoshi/ebiten/v2/internal/thread.(*Thread).Loop
         0     0% 97.91%      0.09s  1.45%  github.com/hajimehoshi/ebiten/v2/internal/uidriver/glfw.(*Input).IsKeyPressed.func1
         0     0% 97.91%      4.48s 72.14%  github.com/hajimehoshi/ebiten/v2/internal/uidriver/glfw.(*Input).update.func2
         0     0% 97.91%      4.78s 76.97%  github.com/hajimehoshi/ebiten/v2/internal/uidriver/glfw.(*UserInterface).Run
         0     0% 97.91%      0.05s  0.81%  github.com/hajimehoshi/ebiten/v2/internal/uidriver/glfw.(*UserInterface).Run.func1
         0     0% 97.91%      0.05s  0.81%  github.com/hajimehoshi/ebiten/v2/internal/uidriver/glfw.(*UserInterface).loop
         0     0% 97.91%      0.05s  0.81%  github.com/hajimehoshi/ebiten/v2/internal/uidriver/glfw.(*UserInterface).run
         0     0% 97.91%      0.05s  0.81%  github.com/hajimehoshi/ebiten/v2/internal/uidriver/glfw.(*UserInterface).update
         0     0% 97.91%      0.09s  1.45%  github.com/hajimehoshi/ebiten/v2/internal/uidriver/glfw.(*UserInterface).update.func4
         0     0% 97.91%      4.78s 76.97%  main.main
         0     0% 97.91%      0.18s  2.90%  runtime._ExternalCode
         0     0% 97.91%      0.27s  4.35%  runtime.checkTimers
         0     0% 97.91%      0.05s  0.81%  runtime.goready.func1
         0     0% 97.91%      0.08s  1.29%  runtime.handoffp
         0     0% 97.91%      0.54s  8.70%  runtime.mPark
         0     0% 97.91%      4.78s 76.97%  runtime.main
         0     0% 97.91%      0.09s  1.45%  runtime.mapaccess2_fast64
         0     0% 97.91%      1.13s 18.20%  runtime.mcall
         0     0% 97.91%      0.07s  1.13%  runtime.mstart
         0     0% 97.91%      0.27s  4.35%  runtime.nanotime (inline)
         0     0% 97.91%      0.54s  8.70%  runtime.notesleep
         0     0% 97.91%      0.31s  4.99%  runtime.notewakeup
         0     0% 97.91%      1.13s 18.20%  runtime.park_m
         0     0% 97.91%      0.05s  0.81%  runtime.ready
         0     0% 97.91%      0.04s  0.64%  runtime.resetspinning
         0     0% 97.91%      1.13s 18.20%  runtime.schedule
         0     0% 97.91%      0.54s  8.70%  runtime.semasleep
         0     0% 97.91%      0.31s  4.99%  runtime.semawakeup
         0     0% 97.91%      0.34s  5.48%  runtime.startlockedm
         0     0% 97.91%      0.17s  2.74%  runtime.startm
         0     0% 97.91%      0.21s  3.38%  runtime.stoplockedm
         0     0% 97.91%      0.43s  6.92%  runtime.stopm
         0     0% 97.91%      0.07s  1.13%  runtime.systemstack
         0     0% 97.91%      0.09s  1.45%  runtime.wakep

[hajimehoshi]

Thanks. I guess ebiten.IsGamepadButtonPressed in inpututil is heavy, but I could not reproduce this yet.

I realized you are using Ebiten 2.0.8. What about 2.1.0?

I'm already seeing my CPU utilization for my runtime spike to 100%.

So did the spike happen only for a short time, or did the CPU usage always keep 100%?

[hajimehoshi]

With goChecker, I have confirmed that the CPU usage has been reduced from 60-70% to 20-30% after updating Ebiten from 2.0.8 to 2.1.0.

[APDevice]

Thanks. After updating the utilization did go down a bit. Its now hovering around 93% on my system. (constant utilization)

[hajimehoshi]

Thanks.

I'll be working on #1489 later. I hope this will mitigate the issue.

BTW, can I see the graph of the pprof result? (Run go tool pprof [pprof file] and then type web)