On Wed, Jan 10, 2018 at 3:13 PM, Gert Wollny <gw.foss...@gmail.com> wrote: > Am Mittwoch, den 10.01.2018, 16:36 +0100 schrieb Gert Wollny: >> This seems to satisfy the sb optimizer, i.e. no regressions in the >> piglits compared to disabling sb for tesselation shaders with >> barriers but enabling them in general. >> --- > > Actually, it seems this is not enough, at least for Tomb Raider which > uses one tessellation control shader with a barrier. The optimizer > reorders the LDS instructions around the barrier in a way that in the > optimized version there are more reads before it than in the original > byte code. > > The number of writes is the same though, and as far as I can tell from > the TGSI, the values written to LDS before the barrier are not read > back within the shader - which makes me wonder whether the barrier is > actually necessary.
If your hardware executes all the vertices in parallel, then a barrier should be unnecessary. -ilia _______________________________________________ mesa-dev mailing list mesa-dev@lists.freedesktop.org https://lists.freedesktop.org/mailman/listinfo/mesa-dev
