AMD prepares OS-level boost clock reporting for future CPUs
AMD is preparing support for a new CPPC field called “HighestFreq”, which would allow the operating system to read a CPU core’s highest frequency directly from firmware.
CPPC, or Collaborative Processor Performance Control, is used by modern AMD processors to communicate performance limits and preferences to the operating system. On Linux, this information is used by the AMD P-State driver. On Windows, similar CPPC data is used for boost behavior and preferred-core scheduling.
The current problem is that CPPC performance values are abstract. They do not always translate cleanly into real clock speeds. AMD says some systems cannot calculate the boost ratio accurately through linear interpolation because the performance-to-frequency mapping is not linear across all cores.
Source: Kernel.org
HighestFreq is meant to solve that by exposing the actual highest frequency when firmware provides it. This would remove the need for the OS to estimate the value. The result should be more accurate CPU capacity calculations and boost ratio handling, which can affect how the scheduler places workloads across cores.
This does not mean future Ryzen CPUs will automatically boost higher. It also does not confirm a new user-facing performance mode. The change is mainly about giving the OS better data, so it can make more accurate decisions when choosing cores and setting performance targets.
The patch is aimed at Linux for now. AMD says the new register is currently proposed through the ACPI Specification Working Group and is trending for inclusion in ACPI 6.7. Windows 11 support is possible if the field becomes part of the ACPI specification and Microsoft adds support for it, but Microsoft has not announced anything yet.
Source: GAZLOG
