240
edits
Changes
→Attempt 1:
We tried to optimize the maze program by removing some of the if statements to reduce thread divergence, however the attempt made the program slower than the phase 2 version and only a little bit faster than the serial version.
'''New Kernels:'''
// Initialize all pixels to black (hex 000)
__global__ void k_drawWalls(png_byte* rows, const short* cells, const int width, const int height, const int len, const int size) {
'''Analysis:'''
For this attempt, the kernel executes for each cell instead of for each byte (in phase 2); it is no longer processing more than 1 pixel in each cell for every thread, which may be the cause to the longer processing time.
=== Attempt 2: ===
We decided to use shared memory in the GPU to improve the speed of the program. However, the maze image does not show correctly: the paths were showing as randomly coloured pixels; the cause is due to the threads setting only a part (1/3, 2/3) of a pixel's values to hexadecimal F.