Reasons for the change to the power frequency
Synopsis:
#include <sys/neutrino.h>
enum nto_power_freq_reason {
_NTO_PFR_NONE,
_NTO_PFR_UNDERFLOW,
_NTO_PFR_OVERFLOW,
_NTO_PFR_WAYPOINT,
_NTO_PFR_THREAD_HISTORY,
_NTO_PFR_JOB_HISTORY,
_NTO_PFR_MASK = 0xffff,
};
Data:
- _NTO_PFR_NONE
- No reason is specified.
- _NTO_PFR_UNDERFLOW
- The CPU cluster's load was less than the specified minimum load for the CPU cluster at the
operating point.
- _NTO_PFR_OVERFLOW
- The CPU cluster's load was greater than the specified maximum load for the CPU cluster at the operating
point.
- _NTO_PFR_WAYPOINT
- The CPU cluster was at a waypoint.
- _NTO_PFR_THREAD_HISTORY
- The kernel changed the CPU cluster frequency due to the history of the thread running on one or more CPUs in the cluster.
- _NTO_PFR_MASK
- The bitmask of allowable operating points.
Description:
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.