On Fri, Aug 21, 2015 at 9:59 PM, Ilia Mirkin <[email protected]> wrote: > On Fri, Aug 21, 2015 at 3:54 PM, Axel Davy <[email protected]> wrote: >> This patch is the result of several discussions on our irc channels. >> >> I amended the commit message to: >> >> st/nine: Always use user constant buffers >> >> We had several reports of users hitting bugs >> with the other path to upload constants, >> and switching to the user constant buffer >> path solves the bugs. >> >> User constant buffers are expected to be slower >> for Nvidia cards, so ideally this patch should be >> reverted when the path is fixed. > > Just for the record: > > User constant buffers will never be fast on NVIDIA hardware. They will > always be at best what you can do in the st, but often worse since you > have more info about what changed in the st that is not passed down to > the driver.
FWIW, I wouldn't mind having partial updates of user constant buffers. This can be accomplished by passing a (huge) bitmask to drivers saying which vec4s need to be re-uploaded. A bitmask consisting of 10 uint32_t elements should be enough for everybody. Marek _______________________________________________ mesa-dev mailing list [email protected] http://lists.freedesktop.org/mailman/listinfo/mesa-dev
