AMD P-State Preferred Core Submitted For Linux 6.9 While Intel Meteor Lake Gets Tuned

The in-development Linux 6.9 kernel is finally landing support for AMD Preferred Core as part of the power management updates for this mid-2024 kernel release.

Since AMD Zen 2 has been the notion of "preferred cores" exposed via ACPI CPPC for CPU cores capable of reaching a higher maximum frequency, which is all the more important with additional Zen 4 / 4C hybrid combinations coming to market. With Linux 6.9, the AMD P-State driver will be able to leverage the preferred cores for higher priority (important) tasks with the kernel scheduler so they are more likely to end up on one of those higher-performing cores.

For those on modern AMD Zen systems where Preferred Core support is enabled from the BIOS, this functionality will be automatically used on Linux 6.9+ -- assuming you are using the AMD P-State driver rather than the generic and former default of ACPI CPUFreq.

Since starting on the Linux patches for AMD Preferred Core last year, they went through 13+ rounds of review and are now being mainlined for Linux 6.9 as part of the power management updates.

The power management pull also allows the Energy Model to be updated dynamically that is important for ARM systems, support for using the LZ4 compression algorithm for hibernation images to speed-up system resume times, and also on the AMD side is a fix for min_perf sysfs assignment to ensure the min/max limit perf values in the AMD P-State driver always stay within their range.

Over on the Intel side is Lunar Lake M and Arrow Lake support for the Intel RAPL driver. There is also an Intel EPP default adjustment in Intel P-State for helping improve Meteor Lake's performance and power efficiency.

Along with the power management pull request, the ACPI pull was also submitted today with various quirks and fixes. A notable AMD change there is ACPI CPPC support for the Threadripper 3000 series for being able to in turn use the AMD P-State CPU frequency scaling driver.