NVIDIA NVK Driver Lands Improvement To Help With Valve's Gamescope

Merged today for next quarter's Mesa 26.3 release is an improvement for the open-source NVIDIA "NVK" Vulkan driver paired with the Nouveau kernel driver. This latest NVK improvement benefits usage of Valve's Gamescope micro-compositor and should help with performance during game recording and remote play.

Mary Guillemard authored an improvement to NVK for exposing the BAR as host cached, which will help the situation with Gamescope. The merge request explained:

"nouveau will always uses CPU cached mappings unless we are on Tegra and need coherency. This patch advertises host cached on BAR memory type.

This is needed for gamescope as it explicitly search for a memory type that is host visible and cached. Before this patch this would cause it to always select sysmem for any allocations that need to be mappable.

This should hopefully at least help game recording and remoteplay performance a bit."

No performance numbers were provided though to quantify the performance impact. In any event an important one line change now ready for Mesa 26.3 and perhaps will be back-ported too for the current Mesa 26.2 stable series.