Optimize performance of the fbdev console for the common case of software-based clearing and image blitting. The commit descripton of each patch contains resuls os a simple microbenchmark. I also tested the full patchset's effect on the console output by printing directory listings (i7-4790, FullHD, simpledrm, kernel with debugging). > time find /usr/share/doc -type f In the unoptimized case: real 0m6.173s user 0m0.044s sys 0m6.107s With optimizations applied: real 0m4.754s user 0m0.044s sys 0m4.698s In the optimized case, printing the directory listing is ~25% faster than before. In v2 of the patchset, after implementing Sam's suggestion to update cfb_imageblit() as well, it turns out that the compiled code in sys_imageblit() is still significantly slower than the CFB version. A fix is probably a larger task and would include architecture-specific changes. A new TODO item suggests to investigate the performance of the various helpers and format-conversion functions in DRM and fbdev. v2: * improve readability for sys_imageblit() (Gerd, Sam) * new TODO item for further optimization Thomas Zimmermann (5): fbdev: Improve performance of sys_fillrect() fbdev: Improve performance of sys_imageblit() fbdev: Remove trailing whitespaces from cfbimgblt.c fbdev: Improve performance of cfb_imageblit() drm: Add TODO item for optimizing format helpers Documentation/gpu/todo.rst | 22 +++++ drivers/video/fbdev/core/cfbimgblt.c | 107 ++++++++++++++++--------- drivers/video/fbdev/core/sysfillrect.c | 16 +--- drivers/video/fbdev/core/sysimgblt.c | 49 ++++++++--- 4 files changed, 133 insertions(+), 61 deletions(-) -- 2.35.1
