Updated: May 06, 2022

Reasons for the change to the power frequency


#include <sys/neutrino.h>
enum nto_power_freq_reason {
    _NTO_PFR_MASK = 0xffff,


No reason is specified.
The CPU cluster's load was less than the specified minimum load for the CPU cluster at the operating point.
The CPU cluster's load was greater than the specified maximum load for the CPU cluster at the operating point.
The CPU cluster was at a waypoint.
The kernel changed the CPU cluster frequency due to the history of the thread running on one or more CPUs in the cluster.
The bitmask of allowable operating points.




The nto_power_freq_reason (_NTO_PFR_*) enumerated values specify the possible reasons the kernel can change the power frequency for a CPU cluster. The reason for a given frequency change can be included in the sigevent sent by the kernel to the power-management process (see the nto_power_parameter's u.freq.ev member in this reference, and Power Management in the Programmer's Guide).

Note: For the purposes of power management (and, therefore, in this documentation) a CPU cluster isn't necessarily equivalent to a CPU cluster as defined in the SoC documentation for your board. It is simply a set of CPUs you create so you can manage their power characteristics together. A CPU cluster may include only a single CPU, or multiple CPUs.