35 lines
1.7 KiB
Markdown
35 lines
1.7 KiB
Markdown
# OpenCL basic examples
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here is my feeble attempt at learning OpenCL, please don't make fun of me too much :hamburger:
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## Configuration
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This currently runs on OS X, and I'm using local header files instead of global header files because I'm unfamiliar with C++. Deal with it. Run the following in a terminal to set up:
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```
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git clone git@github.com:SaintDako/OpenCL-examples.git
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cd OpenCL-examples
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mkdir CL
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curl https://www.khronos.org/registry/cl/api/1.2/cl.hpp -o CL/cl.hpp
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```
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## example 00
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this example is based off of [this example](simpleopencl.blogspot.ca/2013/06/tutorial-simple-start-with-opencl-and-c.html) (example-ception), but it goes a bit further. In the blogspot example, two 10-element vectors are created and a thread is used for each pair of elements. In this example, 10 threads are spawned but two 100-element vectors are used, and it is shown how to split up a specific number of elements per thread.
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## example 01
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Measures the duration of adding two vectors. See the README in the folder for more details.
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## example 02
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Demonstrates that one array can be modified several times without having to re-read and re-write data to and from the GPU.
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## TODO
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- figure out how OpenCL manages memory (when are buffers cleared on the GPU?)
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- figure out how to view the OpenCL assembly code if possible (is warp divergence happening?)
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## Some Notes
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From the [guide on programming OpenCL for NVIDIA](http://www.nvidia.com/content/cudazone/download/OpenCL/NVIDIA_OpenCL_ProgrammingGuide.pdf):
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- **CUDA streaming multiprocessor** corresponds to an OpenCL compute unit
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- **CUDA thread** corresponds to an OpenCL work-item
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- **CUDA thread block** corresponds to an OpenCL work-group
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