Experimental issue : OpenMP on macOS, homebrew llvm + libomp

[rageworx]

Default llvm (clang) of macOS not supports openmp basically.
Experimental performance enhancement for Intel CPU based Mac systems.

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homebrew llvm should be installed by brew install llvm.

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homebrew openmp should be installed by brew install libomp.

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Some makefiles created for testing openmp.
- makefiles/Makefile.homebrewllvm
- Makefiles/Makefile.testmachomebrew

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Generating dylib successfully done, with makefiles/Makefile.homebrewllvm with make dylib.
homebrew llvm doesn't support multi-architecture, Cannot use multiple -arch parameters for universal binary.

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homebrew llvm dylib + macOS native llvm-gcc linking successfully worked.

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Performance extremely increased for butterfly.png on my old MacBook Pro Ratina 13" (2015) CTO, Intel(R) Core(TM) i7-5557U CPU @ 3.10GHz.

>  bin/srcnntest Pictures/butterfly.png --scale=2
- Loading image : Pictures/butterfly.png
- Image loaded type : PNG | 256 x 256 x 3 bytes
- Scaling ratio : 2.00
- Filter : Bicubic
- Processing SRCNN ... Test Ok, took 799 ms.
- Saving rezied result to Pictures/butterfly_resized.png ... Ok.
- Saving convolution result to Pictures/butterfly_convolution.png ... Ok.

• 8233 ms. -> 799 ms. , about 10 times faster.

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Testing performance with test.jpg,

>  bin/srcnntest Pictures/test.jpg --scale=2
- Loading image : Pictures/test.jpg
- Image loaded type : JPEG | 960 x 540 x 3 bytes
- Scaling ratio : 2.00
- Filter : Bicubic
- Processing SRCNN ... Test Ok, took 5770 ms.
- Saving rezied result to Pictures/test_resized.png ... Ok.
- Saving convolution result to Pictures/test_convolution.png ... Ok.

• 67340 ms. -> 5770 ms. , about 10 times faster.

[rageworx]

Conclusion

• openMP makes 10 times better performance on old-generaiton Mac systems, specially Intel CPUs.

[rageworx]

macOS12 OpenMP dylib

libsrcnn-dylib-macOS12-intel-experimental.zip

dependancy

>  otool -L lib/libsrcnn.dylib
lib/libsrcnn.dylib:
	lib/libsrcnn.dylib (compatibility version 0.0.0, current version 0.0.0)
	/usr/local/opt/llvm/lib/c++/libc++.1.dylib (compatibility version 1.0.0, current version 1.0.0)
	/usr/local/opt/llvm/lib/libomp.dylib (compatibility version 5.0.0, current version 5.0.0)
	/usr/lib/libSystem.B.dylib (compatibility version 1.0.0, current version 1311.100.3)

• Additional dylib files
  libsrcnn-dylib-additional-files.zip
  • libc++.dylib
  • libomp.dylib
  • Use install_name_tool to change dylib references if needed.