On 3/24/22 12:18, Thomas Zimmermann wrote:
Hi
Am 24.03.22 um 20:11 schrieb Guenter Roeck:
Hi,
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@suse.de
This patch causes crashes with arm mainstone, z2, and collie emulations. Reverting it fixes the problem.
collie crash log and bisect log attached.
Does it work if you apply the fixes at
https://patchwork.freedesktop.org/series/101321/
?
Yes, it does, specifically the cfb related patch. I sent a Tested-by:.
Thanks, Guenter