Why is my CPU doing all the work while my GPU does almost nothing?

Questions & Answers
1

I’m making a 2D game, a kind of fast moving Tetris.
Below what my Profiler looks like. It always shows about 0.2 ms for the GPU and 3 ms for the CPU!

Why is all the work done by the CPU? Is there a way to transfer some of the tasks to the GPU?
My scripts only take 10% of that CPU usage, so should I assume my coding is not to blame?

Here are a few details about how my project works:

  • I use a sprite packer and I only have
    about 25 draw calls.
  • My entire
    graphics files are about 1 Mb in size
    in total.
  • The sprites are drawn on
    about 10 layers (but drawing them on
    1 layer didn’t solve the problem)
  • I
    never use Instantiate() or Destroy().
    All my prefab instances are pooled
    off screen.
  • 95% of my rendering is
    shown as “Transparent” in Profiler
    (only 5% is Opaque)
  • I use the
    Shader “Sprites/Default” for my whole
    project
  • My audio clips are all
    cached upon Start() as public static
    variables (and they play with an
    annoying delay)
  • I use NGUI

39651-screen-shot-2015-01-27-at-180801.png

2

You GPU isn’t doing to work because you’re not doing any kind of work that gets done on the GPU. If you were to convert your 2D sprites to 3d models and use some advanced shaders you’d start seeing more GPU calculations.

It isn’t a case of calculations being just completely interchangeable between CPU and GPU… certain things take CPU, others take GPU.

You’re not seeing much GPU utilization because your game is almost entirely CPU based operations.

On the upside, you’re getting great performance, probably based on the fact that you’ve followed what are considered best practices.

Great Job!