On Wed, Feb 23, 2022 at 08:38:03PM +0100, Thomas Zimmermann wrote: > Improve the performance of cfb_imageblit() by manually unrolling > the inner blitting loop and moving some invariants out. The compiler > failed to do this automatically. This change keeps cfb_imageblit() > in sync with sys_imagebit(). > > A microbenchmark measures the average number of CPU cycles > for cfb_imageblit() after a stabilizing period of a few minutes > (i7-4790, FullHD, simpledrm, kernel with debugging). > > cfb_imageblit(), new: 15724 cycles > cfb_imageblit(): old: 30566 cycles > > In the optimized case, cfb_imageblit() is now ~2x faster than before. > > v3: > * fix commit description (Pekka) > > Signed-off-by: Thomas Zimmermann <tzimmermann@xxxxxxx> Acked-by: Sam Ravnborg <sam@xxxxxxxxxxxx> The code looks equally complicated now in the sys and cfb variants. Question: What is cfb an abbreviation for anyway? Not related to the patch - but if I have known the memory is lost.. Sam
