SIMD8 Vertex Shaders For Broadwell

Kristian Høgsberg has published a new patch-set but it's not for Wayland, it's for the Intel Mesa driver.

Høgsberg remains out of sight in Wayland's development for the past few months with others stepping to fill in his roles of managing Wayland/Weston, etc. In the meantime at Intel's Open-Source Technology Center he's been working on Skylake support within Intel's Mesa driver and now there's another patch-set out by him this week.

Kristian's latest patches being made public are enabling support for vertex shaders to be generated using Intel's SIMD8 scalar back-end for Broadwell hardware and newer. "With Broadwell we have the option to run vertex shaders in scalar (SIMD8) mode which potentially gives us better throughput and more vertices per thread dispatch. This patch series implements this by repurposing our [fragment shader] backend to also work for vertex shaders."

This patch series for VS SIMD8 support deals with just under one thousand lines of code. This should hopefully lead to a performance win, but of course we're still waiting for Broadwell hardware to actually arrive. The Broadwell ultrabooks / convertible tablets should hopefully not be too many weeks out now in the US (so far it's mostly just the Lenovo Yoga 3 Pro available) and it will be interesting to see how they perform compared to Haswell but the Broadwell desktop CPUs won't see the light of day until 2015. The Broadwell Linux support should be fairly rock solid by now with the open-source Intel developers working on the hardware enablement for more than one year with most work now just being about more fine tuning and optimizations.