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cuorematto
Journeyman III

GPU shader analyzer questions

Hi
what mean Bottleneck (Bi) ALU
Bottleneck(Tri) ALU
Bottleneck(Aniso) ALU ?
Yes ALU i know it is Arithmetic logical unit
but what mean Tri, Bi, Aniso ?
I cannnot find any documentation about the gpu shader analyzer
Do yuo know where can i find some docs ?
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6 Replies

Hi Cuorematto,
Bi, Tri & Aniso refer to the type of texture filtering: Bilinear, Trilinear & Anisotropic. The different methods of texture filtering have difference costs so it is possible for a shader to be ALU bound when using bilinear filtering and texture fetch bound when using anisotropic filtering.

You can find further details on all statistics calculated by GSA in the release notes.

Cheers,
Seth.
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Yes i know ( bi is for bilinear tri is for trilinear and aniso in for anisotropic )
but i cannot understand why we have a bottleneck in ALU ?
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Originally posted by: cuorematto

Yes i know ( bi is for bilinear tri is for trilinear and aniso in for anisotropic )

but i cannot understand why we have a bottleneck in ALU ?


Being bottlenecked by ALU instructions isn't necessarily a bad thing. Your shader's performance has to be limited by something. That you're bottlenecked by ALU means that you're not bottlenecked by texture fetch performance, etc. It also means that if you reduce the ALU cost of your shader you should see an overall improvement in the performance of your shader.

Cheers,
Seth.
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All clear .
I thank you Seth.
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So what does it mean to be bound by "TEX" (texture fetch"? How does this correspond to Brook+ code?

For example, does this mean I have too many local variables? Does it mean that I am using too many registers, etc, etc...

Essentially, knowing nothing about graphics programming (which I don't and you supposedly don't need to in order to code in Brook+/CAL) how does a texture fetch correspond to Brook+ code?
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I think TEX for Brook+ means input streams fetches.
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