Manage Energy vs. Performance Policy via x86 Model Specific Registers
This tool allows software to convey its policy for the relative importance of performance versus energy savings to the processor.
The processor uses this information in model-specific ways when it must select trade-offs between performance and energy efficiency.
This policy hint does not supersede Processor Performance states (P-states) or CPU Idle power states (C-states), but allows
software to have influence where it would otherwise be unable to express a preference.
For example, this setting may tell the hardware how aggressively or conservatively to control frequency in the "turbo range" above the
explicitly OS-controlled P-state frequency range. It may also tell the hardware how aggressively is should enter the OS requested C-states.
Support for this feature is indicated by CPUID.06H.ECX.bit3 per the Intel Architectures Software Developer's Manual.
This tool works only on modern Intel CPUs, run "grep ebp /proc/cpuinfo" to see if your CPU is supported.
The sources can be found in the "tools/power/x86/x86_energy_perf_policy" sub directory of the linux kernel tree.