P-State/CPUFreq Governor Tests With Linux 4.12 For OpenGL/Vulkan Games

[phoronix]

Phoronix: P-State/CPUFreq Governor Tests With Linux 4.12 For OpenGL/Vulkan Games

For those wondering about the impact on gaming of the different CPUFreq vs. P-State CPU frequency scaling drivers and their different governors, here are some fresh tests using an Intel Skylake CPU with Radeon RX Polaris graphics when using the latest Linux 4.12 kernel and Mesa 17.2-dev.

http://www.phoronix.com/vr.php?view=24832

[davidbepo]

it would be nice to add pstate passive + schedutil powersave ...
also its good to see pstate and schedutil working great

[aufkrawall]

schedutil doesn't work great in Dawn of War III (edit: at least not with Vulkan). And with 4.12, it still gives me stuttering in Unigine Valley.

[stqn]

As usual it’s impossible to draw any conclusion from these results, as you can pick any driver/governor and it is sometimes the slowest, sometimes the fastest, sometimes in the middle…

[aufkrawall]

But it seems pstate-performance always works totally fine. Despite of software reading high clocks, my measurements also show low power consumption of it in idle (comparable to pstate powersave).
It's not like a governor that works well in every situation would be impossible, the "balanced" energy profile on Windows does work very well (if you disable coreparking for Ryzen).

[caligula]

Maybe a dumb question, but how does the P-state system know when to run slow or fast? I guess these are the values you can tune in Ryzen PC BIOS? What is the logic that is switching between the modes?

[Hi-Angel]

Maybe a dumb question, but how does the P-state system know when to run slow or fast? I guess these are the values you can tune in Ryzen PC BIOS? What is the logic that is switching between the modes?

Depends on values visible to scaling governors, and values from specific hw registers (if present). Just google something like "<governor_name> docs", e.g. "schedutil docs" gives this nice article https://01.org/linuxgraphics/gfx-doc...m/cpufreq.html