Much Faster Tessellation Is Coming For AMD's RadeonSI Gallium3D

Bas Nieuwenhuizen has announced his work on "offchip tessellation" support for the RadeonSI Gallium3D driver to provide dramatically better OpenGL tessellation performance.

His set of 14 patches to RadeonSI explain:

This patchset implements offchip tessellation after which we can finally process more than one patch per wave without decreasing tessmark scores.

For tessmark this improves performance by ~20% for the x32 case and ~80% for the x64 case. x8 and x16 have roughly the same performance as before. Unigine heaven gets 43 fps compared to 28 before (roughly +50%). Amdgpu-pro gets 44 fps for heaven. For Shadow of Mordor the performance changes from 28 fps to 40 fps (roughly +40%).

Nieuwenhuizen is also still exploring a few other areas for further improving the RadeonSI tessellation performance too. So far this patch series amounts to a few hundred lines of new code for delivering this significant performance boost for demanding, modern titles. The Mesa 11.3 feature freeze is planned for the end of next week so hopefully we'll be able to see these tessellation optimizations land in time to avoid having to wait another three months before they'll be seen in the stable release.