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GPGPU

Ked

Result

Computation of Normal VectorImage resolution: 640 x 480CPU: 625 clock timeGPU: 125 clock time

Result

Computation of Normal VectorImage resolution: 1280 x 1024CPU: 2500 clock timeGPU: 172 clock time

OK, What is GPU

A graphics accelerator incorporates custom microchips which contain special mathematical operations commonly used in graphics rendering.

GPGPU

• General purpose computing on GPU

GPGPU

GPGP

GP2

(boring RD -.-||)‏hi, I am R2-D2

Why faster

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Why faster Why faster

CPU GPUGeneral purpose Specialized hardware

Serial execution Parallel execution

Minimum latency Maximum throughput

Development tools:

Focus on GPGPU CUDA:

Compute Unified Device Architecture

Developed by NVIDIA

C like language

Full developing environment

Compiler

Debugger

Math libraries

Development tools:

Focus on GPGPU Advantage:

Shared memory amongst threads

16k

Faster downloads and readbacks to and from GPU

Full support for integer and bitwise operations

Development tools:

Shader programming ARB low-level assembly language

OpenGL shading language

Cg programming language

DirectX high-level shader language

Development tools:

Shader programming

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Development tools:

Shader programming Developing tools of GLSL:

Pipeline of GPU processing

Shader programming

Vertex shader

Fragment shader

Geometry shader

RenderMan shading language

Developed by Pixar has uncompromising image

quality as its fundamental goal

Light shader

Displacement shader

Surface shader

Volume shader

Imager shader

Vertex shader Fragment shader

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Streaming of fragment shader

Stream processing is a computer programming paradigm,

related to SIMD, that allows some applications to more

easily exploit a limited form of parallel processing. Such

applications can use multiple computational units, such

as the floating point units on a GPU, without explicitly

managing allocation, synchronization, or communication

among those units.

Branch of fragment shader

Conception of GPGPU

Textures => Computing arrays Vertex Coordinates => Computational range Fragment programs => Computation Read from framebuffer => Get result

Case study:

Computation of normal vector

Normal(V0) =[ normal(F401) +normal(F102) +normal(F203) +normal(F304) ] / 4

Normal(F102) = cross(v1v0, v2v0)‏

Prepare:

Choose graphic card

Prepare:

Test the graphic card

need

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Use GLSL in BCB environment:

Call GLee library Other choice: GLew

Install shader:

Run-time building

Texture:

Computing array

Vertex coordinate:

Computational range

Fragment program:

Computation

Read from framebuffer:

Get result

FameBuffer Object is a better choice

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Trivia:

Ghost in numerical computing

Review the result

Image resolution: 640 x 480CPU: 625 clock timeGPU: 125 clock time

Image resolution: 1280 x 1024CPU: 2500 clock timeGPU: 172 clock time

Reference

GPU Gems 2

OpenGL Shading Language

OpenGL Programming Guide

Dominik Göddeke-- GPGPU::Basic Math Tutorial(website)‏

GPGPU: SIGGRAPH 2004 course

Batch, batch, batch: what does it really means

Thx.