Lionel Landwerlin
e5dfff0946
When lowering a single instruction with a destination VGRF to 2 or more, the VGRF is now considered partially written by each generated instruction and that increases its liveness especially in loops. Thus potentially increasing the number of spills/fills due to register allocation. Putting an UNDEF instruction in front of the lowered instructions allows the IR to limit the liveness of the VGRF, reducing register pressure. This has a pretty dramatic effect on spills/fills for RT shaders. Here the stats on Q2RTX shaders on DG2 (wipping out any spills/fills due to register allocation) : Instructions in all programs: 26150 -> 24955 (-4.6%) SENDs in all programs: 1148 -> 1148 (+0.0%) Loops in all programs: 4 -> 4 (+0.0%) Cycles in all programs: 392179 -> 332787 (-15.1%) Spills in all programs: 132 -> 116 (-12.1%) Fills in all programs: 262 -> 154 (-41.2%) Shader-db results on TGL : total instructions in shared programs: 21158140 -> 21158377 (<.01%) instructions in affected programs: 76629 -> 76866 (0.31%) helped: 18 HURT: 20 helped stats (abs) min: 1 max: 60 x̄: 18.89 x̃: 12 helped stats (rel) min: 0.21% max: 3.61% x̄: 1.02% x̃: 0.77% HURT stats (abs) min: 1 max: 79 x̄: 28.85 x̃: 18 HURT stats (rel) min: 0.04% max: 2.81% x̄: 1.13% x̃: 0.79% 95% mean confidence interval for instructions value: -4.82 17.30 95% mean confidence interval for instructions %-change: -0.34% 0.57% Inconclusive result (value mean confidence interval includes 0). total loops in shared programs: 5753 -> 5753 (0.00%) loops in affected programs: 0 -> 0 helped: 0 HURT: 0 total cycles in shared programs: 798856834 -> 798870688 (<.01%) cycles in affected programs: 6208395 -> 6222249 (0.22%) helped: 22 HURT: 17 helped stats (abs) min: 2 max: 8794 x̄: 1438.18 x̃: 782 helped stats (rel) min: 0.05% max: 2.28% x̄: 0.63% x̃: 0.44% HURT stats (abs) min: 2 max: 19178 x̄: 2676.12 x̃: 1358 HURT stats (rel) min: 0.04% max: 23.49% x̄: 2.25% x̃: 0.71% 95% mean confidence interval for cycles value: -952.19 1662.65 95% mean confidence interval for cycles %-change: -0.64% 1.90% Inconclusive result (value mean confidence interval includes 0). total spills in shared programs: 4078 -> 4066 (-0.29%) spills in affected programs: 40 -> 28 (-30.00%) helped: 2 HURT: 0 total fills in shared programs: 2856 -> 2832 (-0.84%) fills in affected programs: 127 -> 103 (-18.90%) helped: 2 HURT: 0 total sends in shared programs: 998554 -> 998554 (0.00%) sends in affected programs: 0 -> 0 helped: 0 HURT: 0 LOST: 0 GAINED: 0 Total CPU time (seconds): 2346.06 -> 2304.80 (-1.76%) Signed-off-by: Lionel Landwerlin <lionel.g.landwerlin@intel.com> Reviewed-by: Francisco Jerez <currojerez@riseup.net> Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/18657>
`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 `OFTC's #dri-devel <irc://irc.oftc.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.