Ian Romanick
d69ba58644
When most of these patterns were created, we believed, incorrectly, that fsat(NaN) was NaN. We have since realized that fsat(NaN) is zero. Originally, this changed the patterns to use is_a_number. This didn't help any shaders, so it's easier to just drop the optimizations. This commit crossed paths with4c3ad4d065("nir/algebraic: mark more optimization with fsat(NaN) as inexact") andbc123c396a("nir/algebraic: mark some optimizations with fsat(NaN) as inexact"). Given that these don't impact very many shaders, it seems safer to just remove them. As discussed in https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/8716, I tried modifying these patterns to use !(b cmp a). Unfortunately, on Intel GPUs, the results were much worse than just removing the patterns altogether. Some other related patterns will be addressed in later commits. There are still a number of patterns that use the identity fsat(1-X) == 1 - fsat(X). If X is NaN, the former is zero while the latter is 1.0. I haven't evaluted these patterns yet. If changes are needed in these patterns, it should be a separate commit anyway. v2: Replace arrow `=>` with `->` in comments because the `=>` looks a lot like `<=` comparison. Suggested by Rhys. Fixes:92b75c126b("nir/algebraic: Replace checks that a value is between (or not) [0, 1]") Fixes:a7f0c57673("nir/algebraic: Eliminate useless fsat() on operand of comparison w/value in (0, 1)") Reviewed-by: Rhys Perry <pendingchaos02@gmail.com> All Intel hardware had similar results. (Ice Lake shown) total instructions in shared programs: 20029060 -> 20029670 (<.01%) instructions in affected programs: 69236 -> 69846 (0.88%) helped: 0 HURT: 263 HURT stats (abs) min: 1 max: 20 x̄: 2.32 x̃: 1 HURT stats (rel) min: 0.30% max: 11.11% x̄: 1.35% x̃: 0.98% 95% mean confidence interval for instructions value: 1.86 2.78 95% mean confidence interval for instructions %-change: 1.18% 1.52% Instructions are HURT. total cycles in shared programs: 979821278 -> 979834425 (<.01%) cycles in affected programs: 1476848 -> 1489995 (0.89%) helped: 49 HURT: 204 helped stats (abs) min: 1 max: 812 x̄: 102.31 x̃: 20 helped stats (rel) min: 0.01% max: 21.43% x̄: 2.23% x̃: 0.52% HURT stats (abs) min: 2 max: 2600 x̄: 89.02 x̃: 16 HURT stats (rel) min: 0.04% max: 27.27% x̄: 1.49% x̃: 0.72% 95% mean confidence interval for cycles value: 13.18 90.75 95% mean confidence interval for cycles %-change: 0.29% 1.25% Cycles are HURT. No fossil-db changes. Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/10012>
`Mesa <https://mesa3d.org>`_ - The 3D Graphics Library ====================================================== Source ------ This repository lives at https://gitlab.freedesktop.org/mesa/mesa. Other repositories are likely forks, and code found there is not supported. Build & install --------------- You can find more information in our documentation (`docs/install.rst <https://mesa3d.org/install.html>`_), but the recommended way is to use Meson (`docs/meson.rst <https://mesa3d.org/meson.html>`_): .. code-block:: sh $ mkdir build $ cd build $ meson .. $ sudo ninja install Support ------- Many Mesa devs hang on IRC; if you're not sure which channel is appropriate, you should ask your question on `Freenode's #dri-devel <irc://chat.freenode.net#dri-devel>`_, someone will redirect you if necessary. Remember that not everyone is in the same timezone as you, so it might take a while before someone qualified sees your question. To figure out who you're talking to, or which nick to ping for your question, check out `Who's Who on IRC <https://dri.freedesktop.org/wiki/WhosWho/>`_. The next best option is to ask your question in an email to the mailing lists: `mesa-dev\@lists.freedesktop.org <https://lists.freedesktop.org/mailman/listinfo/mesa-dev>`_ Bug reports ----------- If you think something isn't working properly, please file a bug report (`docs/bugs.rst <https://mesa3d.org/bugs.html>`_). Contributing ------------ Contributions are welcome, and step-by-step instructions can be found in our documentation (`docs/submittingpatches.rst <https://mesa3d.org/submittingpatches.html>`_). Note that Mesa uses gitlab for patches submission, review and discussions.