1.Dd February 17, 2014 2.Dt PERFBIAS 4 3.Os 4.Sh NAME 5.Nm perfbias 6.Nd device driver for Intel performance-energy bias support 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 perfbias" 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 19perfbias_load="YES" 20.Ed 21.Sh DESCRIPTION 22The 23.Nm 24driver provides support for Intel performance-energy bias, 25which allows OS to guide logical CPU heuristic of power management features 26to favor increasing dynamic performance or conserve energy consumption. 27Each logical CPU could has its own performance-energy bias setting. 28.Sh MIB Variables 29Each logical CPU's performance-energy bias is controlled through the 30.Va machdep.perfbias Ns Em X 31branch of the 32.Xr sysctl 3 33MIB. 34.Em X 35is the logical CPU id. 36.Bl -tag -width "hint" 37.It Va hint 38Valid value ranges from 0 to 15, inclusive. 39Set it to 0 to give the highest performance. 40Set it to 15 to maximize energy saving. 41.El 42.Sh SEE ALSO 43.Xr sysctl 3 , 44.Xr sysctl 8 45