Promote small dense UBO access to push constants

Question

Promote small dense UBO access to push constants

chrisforbes opened this issue 11 years ago · 3 comments

When porting from DX10/11 to GL, it's natural to use UBO for absolutely everything, but this carries a stiff perf penalty on our driver. If we have small UBOs and a dense block of variables within them are used, we should try to promote that to push constants so they are delivered automatically to the shader kernel.

Answer 1 · 2014-10-12T08:45:36.000Z

On Haswell, the RS has gather-from-memory capability which can be used to fetch from UBO and push the resulting data into the kernels.

Answer 2 · 2014-10-12T08:46:45.000Z

Note: RS requires a change to our binding table management, since the HW wants to control it. We get binding table edit commands instead.

Also tons of weird issues in Haswell implementation; PRM documents required workarounds to prime the RS.

Answer 3 · 2017-11-03T23:42:57.000Z

RS is apparently a disaster. Rest of this is done.