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.Dd March 17, 2011
.Dt EST 4
.Os
.Sh NAME
.Nm est
.Nd Enhanced SpeedStep Technology support
.Sh SYNOPSIS
To compile this driver into the kernel, place the following line in your
kernel configuration file:
.Bd -ragged -offset indent
.Cd "options CPU_ENABLE_EST"
.Ed
.Pp
To load this driver as a module at boot time, place the following line in
.Xr loader.conf 5 :
.Bd -literal -offset indent
est_load="YES"
.Ed
.Sh DESCRIPTION
The
.Nm
driver provides support for the
.Tn Enhanced SpeedStep Technology
present in newer CPUs.
.Pp
If the CPU is supported
.Nm
creates the following variables in the
.Va machdep.est
branch of the
.Xr sysctl 3
MIB.
.Bl -tag -width ".Va frequency.available" -offset indent
.It Va frequency.available
The list of frequencies supported by
.Nm
for the CPU (read only).
.It Va frequency.current
The current CPU frequency (read only).
.It Va frequency.target
The target CPU frequency (read/write).
.El
.Pp
An associated userland daemon which is part of the
.Xr pkgsrc 7
collection
.Pa ( sysutils/estd )
can be used to dynamically set the CPU frequency depending on utilization.
.Sh HISTORY
The
.Nm
driver first appeared in
.Dx 1.5 .