CPUFreq vs. P-State CPU Scaling Governor Tests On Various Vulkan/OpenGL Games

[phoronix]

Phoronix: CPUFreq vs. P-State CPU Scaling Governor Tests On Various Vulkan/OpenGL Games

With the recent release of some new Linux games like the Serious Sam 2017 update and Max Max, also with featuring Vulkan renderers, here are some fresh Intel P-State vs. ACPI CPUFreq frequency scaling driver and governor comparisons with a variety of Linux games.

http://www.phoronix.com/vr.php?view=24479

[Sonadow]

In Fedora and Ubuntu, I realized that P-state always loves to throttle up to the maximum frequency at the drop of a hat, regardless of whether the workload in question actually benefits from the high frequency.

And even when idling, P-state never actually idles at the processor's lowest possible frequency. The lowest my processor can go is 400MHz, but the idling is always somewhere around the 500MHz region.

[monte84]

Would be great to see this on Ryzen. Would also like to see the actual wattage at idle between the different governors.

[davidbepo]

why no schedutil?

[Michael]

why no schedutil?

Because it wasn't in the Ubuntu 16.10 kernel...

[fuzz]

I've been using schedutil... seems more flexible than ondemand.

[tildearrow]

Michael Sorry, typo:

Tesseract is a game that does tend to be impacted much more by changes in the CPU scaling driver/governo than other games.

[andrebrait]

In Fedora and Ubuntu, I realized that P-state always loves to throttle up to the maximum frequency at the drop of a hat, regardless of whether the workload in question actually benefits from the high frequency.

And even when idling, P-state never actually idles at the processor's lowest possible frequency. The lowest my processor can go is 400MHz, but the idling is always somewhere around the 500MHz region.

Yeah. Same here with my Kaby Lake laptop. If you run powertop, you can observe cpufreq parks the cores and keeps them mostly in the lowerst power configurations (package included) with is S10, I think. Pstate won't go lower than S6 or something like that.

There's a reason why Dell ships their Ubuntu laptops with cpufreq instead of pstate.

[andrebrait]

In Fedora and Ubuntu, I realized that P-state always loves to throttle up to the maximum frequency at the drop of a hat, regardless of whether the workload in question actually benefits from the high frequency.

And even when idling, P-state never actually idles at the processor's lowest possible frequency. The lowest my processor can go is 400MHz, but the idling is always somewhere around the 500MHz region.

Dell ships their laptops with cpufreq instead of pstate. Makes sense, right?

[Gusar]

egardless of whether the workload in question actually benefits from the high frequency.

*Every* task benefits from the high frequency. It allows the CPU to finish the task as fast as possible, so it can go back into deep idle states as quickly as possible.