Performance Inspector Show GPU/CPU Execution?

toneburst's picture

Would it be possible for Performance Inspector to be able to show if CIFilter and/or GLSL patches were being executed on the GPU, or were falling-back to software-rendering? I have a feeling this is a pretty complex issue, but it would be good to know if a particular chunk of CIKernel/GLSL code was causing software-fallback or not.

Any thoughts, guys?

a|x http://machinesdontcare.wordpress.com

cwright's picture
no need

To see if CoreImage executes in software mode or not, simply look for lines like this in Console.app:

2/25/09 11:51:00 AM [0x0-0x466466].com.apple.QuartzComposer.editor[53251] CoreImage: multiplyEffect: falling back to software 
2/25/09 11:51:02 AM [0x0-0x466466].com.apple.QuartzComposer.editor[53251] CoreImage: multiplyEffect: fragment program exceeds native limits: 
2/25/09 11:51:02 AM [0x0-0x466466].com.apple.QuartzComposer.editor[53251]   7/11 attrs, 16/16 temps, 17/32 params 106/96 insns 
2/25/09 11:51:02 AM [0x0-0x466466].com.apple.QuartzComposer.editor[53251]   76/64 alu insns, 30/32 tex insns, 2/4 tex indirections

To see if GLSL executes on the GPU, inspect the output -- if you see what you expect, it's working on the GPU, otherwise, it fails (fragment shaders are tricky to virtualize in software -- vertex shaders not as difficult). The graphics card drivers can silently drop to software, but no one has access to when that happens -- when compiling GLSL shaders, you simply get a pass/fail result, and possibly a descriptive string saying why it failed ("Parse Error on line 42", or "76/64 alu insns, 30/32 tex insns, 2/4 tex indirections" or similar).