CLOCKMOD(4)

NAME
clockmod - device driver for Intel software controlled clock modulation

SYNOPSIS
To compile this driver into the kernel, place the following line in your kernel configuration file:

device clockmod

Alternatively, to load the driver as a module at boot time, place the following line in loader.conf(5):

    clockmod_load="YES"

DESCRIPTION
The clockmod driver provides support for Intel software controlled clock modulation, which reduces CPU core's duty cycle to reduce the power consumption. A clock moduation domain contains logical CPUs on the same CPU core. All logical CPUs in the same clock modulation domain will have the same duty cycle setting.

MIB Variables
Clock modulation domain's information and controlling is provided by machdep.clockmod_domX branch of the sysctl(3) MIB.

members
    Logical CPUs belong to this clock modulation domain.

available
    Available duty cycle settings for this clock modulation domain.

select
    The current duty cycle setting for this clock modulation domain. It could be set to any value listed in available. The lower duty cycle the more power saving.

SEE ALSO
sysctl(3), sysctl(8)