1.Dd February 17, 2014 2.Dt CLOCKMOD 4 3.Os 4.Sh NAME 5.Nm clockmod 6.Nd device driver for Intel software controlled clock modulation 7.Sh SYNOPSIS 8To compile this driver into the kernel, 9place the following line in your 10kernel configuration file: 11.Bd -ragged -offset indent 12.Cd "device clockmod" 13.Ed 14.Pp 15Alternatively, to load the driver as a 16module at boot time, place the following line in 17.Xr loader.conf 5 : 18.Bd -literal -offset indent 19clockmod_load="YES" 20.Ed 21.Sh DESCRIPTION 22The 23.Nm 24driver provides support for Intel software controlled clock modulation, 25which reduces CPU core's duty cycle to reduce the power consumption. 26A clock moduation domain contains logical CPUs on the same CPU core. 27All logical CPUs in the same clock modulation domain will have the same 28duty cycle setting. 29.Sh MIB Variables 30Clock modulation domain's information and controlling is provided by 31.Va machdep.clockmod_dom Ns Em X 32branch of the 33.Xr sysctl 3 34MIB. 35.Bl -tag -width "available" 36.It Va members 37Logical CPUs belong to this clock modulation domain. 38.It Va available 39Available duty cycle settings for this clock modulation domain. 40.It Va select 41The current duty cycle setting for this clock modulation domain. 42It could be set to any value listed in 43.Va available . 44The lower duty cycle the more power saving. 45.El 46.Sh SEE ALSO 47.Xr sysctl 3 , 48.Xr sysctl 8 49