RadeonSI Patches Boost Deus Ex: MD Performance By ~70%

Marek Olšák is off to a good start with performance optimizations of the RadeonSI Gallium3D open-source driver stack in 2017.

Marek has posted a series of patches today vastly boosting the performance of the recent Linux game port Deus Ex: Mankind Divided when using RadeonSI. He explained of the patches, "These patches optimize our SDMA usage and implement buffer clearing. They also turn SDMA IBs into de-facto preambles of GFX IB, because any clear that is also the first buffer use is pushed. It improves DeusEx:MD performance by 70% and the slow ClearBuffer implementation was the main problem. Using SDMA instead of slow CP DMA restored performance, though we might also consider using a compute shader instead of SDMA, because the compute shader can always be asynchronous to graphics in this case (SDMA isn't asynchronous due to the IB dependency)."

This is great news as currently the Deus Ex: Mankind Divided performance is awful with RadeonSI:

An example of the slow Deus Ex: MD performance with RadeonSI, from the results in the recent 31-Way NVIDIA GeForce / AMD Radeon Linux OpenGL Comparison - End-Of-Year 2016.

Once this set of 12 patches land in Mesa Git, will certainly be running some fresh RadeonSI GCN GPU benchmarks.