raspberrypi/linux — pull request #314 by hglm (2013-06-20 00:53:43+00:00)
Title: Speed up framebuffer console text rendering

These changes optimize the console framebuffer monochrome imageblit function used for text rendering in the console for 16bpp and 32bpp pixel depths. A significant speed-up is attained.

Only drivers/video/cfbimgblt.c is affected. For clarity, the changes are split into two parts, one that fixes trailing whitespace and inconsistent tab usage in the original file by running it through indent, and one implementing the actual changes.

Some benchmark results from running cat on a big text file:

Console framebuffer resolution 1280x1024, 8x16 font.

Without patch, 16bpp:

real 1m41.713s
user 0m0.000s
sys 1m41.050s

With patch, 16bpp (speed up 39%):

real 1m12.982s
user 0m0.000s
sys 1m12.840s

Without patch, 32bpp:

real 2m51.666s
user 0m0.000s
sys 2m51.350s

With patch, 32bpp (speed up 52%):

real 1m52.593s
user 0m0.000s
sys 1m52.400s