Multiproc-openCL

This repository is for the learning purpose of GPGPU with OpenCL.

Performance comparison

• values are not averaged and are taken from the first run. They are not checked to be within 95% confidence interval. We are currently working on it.

pre operations times are populated in data/out/profile_data_X_MT.txt or data/out/profile_data_X.txt where X is the image number.

Operation	Single Thread (μs)	Multi Thread (μs)	Speedup	OpenCL without memory copy times (μs)	Speedup
Image Read	500,027.188	-	-	-	-
Image Save	75,909.508	-	-	-	-
Resize	2,945.700	2,858.50	1.03	514.72	5.7
Grayscale	3,676.700	1,143.50	3.22	111.16	33.1
Blur	170,868.61	28,222.40	6.05	1,151.52	148.4
Disparity	79,181,840.00	17,300,552.00	4.58	3,135,732.53	25.3
Cross Check	2,717.650	1,328.25	2.05	299.92	9.1
Occulsion	4,664.750	1,551.35	3.01	456.60	10.2

Folder structure

• learning

  • platform: Get platforms and devices
  • context: Set the context and get the reference count
  • program: Create program and build the program
  • kernel: Create kernels and search for a specific kernel by name
  • command-queue: Create the command queue and enque kernel execution commands
  • buffer: Create buffer and sub-buffer, get info
  • mapNcopy: Mapping and copying buffer objects
  • hello-world: First kernal program

• project

  • matAdd: Added two matrixes using C and OpenCL.
  • opencl_flow_ex3: OpenCL implementation of Image resizing, gray scaling and applied gaussian blur.

Implementation locations

• OpenCL and C matrix addition : project/matAdd/
• OpenCL resize, grayscale, gaussian filter : project/opencl_flow_ex3
• save image (C) : void saveImage(const char *filename, Image *image) in src/pngloader/pngloader.c
• read image (C) : Image *readImage(const char *filename) in src/pngloader/pngloader.c
• resize (C) : Image *resizeImage(Image *input) in src/pngloader/pngloader.c
• grayscale scale (C) : Image *grayScaleImage(Image *input) in src/pngloader/pngloader.c
• occlusion_filling (C) : occulsion_filling.c
• cross_checking (C): cross_checking.c
• 5x5 filter (C) :
  • float applyFilterToNeighboursFloat(float *neighbours, unsigned char *filter, int size) in src/pngloader/pngloader.c
  • getGaussianFilter in driver.c

How to run

• clone the repository
• create a build folder inside the repository

To Build

  mkdir build
  cd build
  cmake -DCMAKE_BUILD_TYPE=Release ..
  make -j

• Output images will be saved in data/out folder

Running

• Run single threaded implementation

  ./Multiproc-openCL single
  ./Multiproc-openCL single -benchmark
  

• Run multithreaded implementation. Also support benchmarking

  ./Multiproc-openCL mp
  ./Multiproc-openCL mp -benchmark
  

• Run opencl implementation

  ./Multiproc-openCL opencl
  ./Multiproc-openCL opencl -benchmark
  

• Run opencl optimized implementation

  ./Multiproc-openCL opencl_opt
  ./Multiproc-openCL opencl_opt -benchmark
  

Run C multithreaded implementation

• After building the project run.

./Multiproc-openCL mp

Run opencl implementation

• After building the project run.

./Multiproc-openCL opencl

Outputs

• One of the Inputs 2940x2016

• Resized and grayscale 735x504

• Blur filter added 735x504

• Left disparity 735x504

• Cross check 735x504

• Occulsion filled 735x504

Reference

• OpenCL in Action by Matthew Scarpino

Work Diary helper commands

git log --since="last month" --pretty=format:"%ad -- %an -- %h %s"