Intel Has More P-State Changes Coming For Linux 4.12

Written by Michael Larabel in Intel on 23 March 2017 at 12:45 PM EDT. 4 Comments
Tuning the P-State CPU frequency scaling driver for the Linux kernel feels like a never-ending process. While it's been around for years and continues to be refined, for some Intel CPUs on some workloads, the CPUFreq scaling driver leads to be better performance and even Intel's own Clear Linux distribution is using CPUFreq by default. With Linux 4.12, more intel_pstate revisions are taking place.

Rafael Wysocki, Linux power management expert and Intel developer, has posted a new set of patches for further tuning P-State's CPU frequency scaling behavior.

He commented on at the opening of the patch series, "This series of patches makes changes to intel_pstate that will modify its behavior in visible ways and add documentation describing the driver's interface and behavior after those changes. It is targeted at 4.12."

The patches affect the P-State active mode (default) behavior as it has turned out to be problematic and the new behavior is explained with this patch. One of the other patches now uses the load-based P-State mode selection more widely, for basically all hardware except servers -- as defined by the ACPI preferred profile. Another patch supports HWP processors in all operation modes.

As usual whenever there's a large CPUFreq/P-State change, we'll have fresh benchmarks with the different drivers and governors when Linux 4.12 rolls into town.
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Michael Larabel is the principal author of and founded the site in 2004 with a focus on enriching the Linux hardware experience. Michael has written more than 20,000 articles covering the state of Linux hardware support, Linux performance, graphics drivers, and other topics. Michael is also the lead developer of the Phoronix Test Suite, Phoromatic, and automated benchmarking software. He can be followed via Twitter, LinkedIn, or contacted via

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