Linux 6.13 PM Switches EPYC Turin To AMD P-State, More Aggressive Default For Intel GNR

The power management subsystem updates have been submitted for the newly opened Linux 6.13 merge window. As covered within individual articles over the past few weeks, the Linux 6.13 power management updates include some notable changes for both AMD and Intel systems.

Most notable with Linux 6.13 power management are AMD EPYC 9005 "Turin" CPUs defaulting to the AMD P-State driver. AMD Ryzen CPUs since Zen 2 with ACPI CPPC support have long been using the AMD P-State driver by default while the AMD EPYC server processors have kept to using the ACPI CPUFreq driver. Finally with Linux 6.13 the AMD P-State driver will be used by default on AMD EPYC 9005 "Turin" processors for providing better power efficiency. My initial 5th Gen AMD EPYC benchmarks with AMD P-State using the code for Linux 6.13 have been quite positive so far and I'll have more EPYC benchmarks on Linux 6.13 soon. Prior generations of AMD EPYC servers will keep to using the generic ACPI CPUFreq driver.

The AMD P-State driver with this release has also been updated to set the initial scaling frequency policy lower-bound to be the lowest non-linear frequency, amd-pstate driver clean-ups, and other AMD P-State driver clean-ups/improvements.

Over on the Intel side the the balance-performance Energy Performance Preference (EPP) value has been updated for Intel Xeon 6 P "Granite Rapids" processors to prefer a more performance-biased default. This should yield better Granite Rapids performance out-of-the-box for those not using the performance governor already.

Also on the Intel side is Granite Rapids D support within the Intel Idle driver.

More details on all of the power management changes to find with Linux 6.13 via the PM pull request.