New Intel Linux Graphics Driver Patches Allow Tuning For Up To 10~15% Better Performance
The set of Intel i915 Linux kernel graphics driver patches are about exposing the Intel RPS (Requested Power State) up/down thresholds. Right now the Intel Linux kernel driver has static values set for the up/down thresholds between power states while these patches would make them dynamically configurable by user-space. Google engineer Syed Faaiz Hussain raised the issue that they experimented with the Intel RPS tuning and were able to manage up to 15% better performance. With Counter-Strike: Global Offensive with OpenGL was a 14.5% boost, CS:GO with Vulkan was 12.9% faster, and Civilization VI with OpenGL was 11% faster while Strange Brigade was unchanged. No other game numbers were provided.
But as this is about changing the threshold for how aggressively the Intel graphics hardware switches power states, the proposed patches leave it up to user-space to adjust the thresholds as they wish. Google engineers are interested in hooking this into Feral's GameMode so that the values could be automatically tuned when launching games and then returning to their former state when done gaming, in order to maximize battery life / power efficiency.
There is this GitLab ticket that outlines the problem and their observations for better performance with RPS threshold tuning. Posted by Intel to the dri-devel list are a set of four patches to get the RPS up/down thresholds exposed via sysfs for maximizing game performance and/or best power efficiency.
The only downside with these current patches are that they work only for non-GuC based platforms... So the latest Alder/Raptor Lake notebooks as well as Intel DG2/Alchemist discrete graphics currently don't aren't able to make use of this tuning option.