On Fri, 25 Jun 2010 09:58:34 +0100
Colin Watson <address@hidden> wrote:
I recently posted ("Subject: [PATCH] Optimise memset on i386" -
sorry, I don't seem to have a route to lists.gnu.org at the moment so
I can't post an archive link) about optimising GRUB's video
initialisation, and hinted that it might be possible to do better by
implementing MTRRs as well in order to allow the system to combine
writes to video memory rather than taking a cache stall for every
single write. I can report that, at least on the hardware I was
using, it does make a significant difference: filling the screen with
solid colour now takes 10 milliseconds rather than 160! This ended
up shaving about a second off the boot time of the project I'm
working on.
In addition to the improved startup speed, I see the potential for a
huge increase in graphical menu responsiveness if caching is enabled.
Would framebuffer draw and image blitting performance be improved by
using write-combining with MTRRs?