1.\" 2.\" Copyright (c) 2019 Intel Corporation 3.\" 4.\" Redistribution and use in source and binary forms, with or without 5.\" modification, are permitted provided that the following conditions 6.\" are met: 7.\" 1. Redistributions of source code must retain the above copyright 8.\" notice, this list of conditions and the following disclaimer. 9.\" 2. Redistributions in binary form must reproduce the above copyright 10.\" notice, this list of conditions and the following disclaimer in the 11.\" documentation and/or other materials provided with the distribution. 12.\" 13.\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 14.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 15.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 16.\" ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 17.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 18.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 19.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 20.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 21.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 22.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 23.\" SUCH DAMAGE. 24.\" 25.\" $FreeBSD$ 26.\" 27.Dd April 21, 2020 28.Dt HWPSTATE_INTEL 4 29.Os 30.Sh NAME 31.Nm hwpstate_intel 32.Nd Intel Speed Shift Technology driver 33.Sh SYNOPSIS 34To compile this driver into your kernel 35place the following line in your kernel 36configuration file: 37.Bd -ragged -offset indent 38.Cd "device cpufreq" 39.Ed 40.Sh DESCRIPTION 41The 42.Nm 43driver provides support for hardware-controlled performance states on Intel 44platforms, also known as Intel Speed Shift Technology. 45.Sh LOADER TUNABLES 46.Bl -tag -width indent 47.It Va hint.hwpstate_intel.0.disabled 48Can be used to disable 49.Nm , 50allowing other compatible drivers to manage performance states, like 51.Xr est 4 . 52Defaults to 53.Dv Qq 0 54(enabled). 55.It Va machdep.hwpstate_pkg_ctrl 56Selects between package-level control (the default) and per-core control. 57.Dv Qq 1 58selects package-level control and 59.Dv Qq 0 60selects core-level control. 61.El 62.Sh SYSCTL VARIABLES 63The following 64.Xr sysctl 8 65values are available 66.Bl -tag -width indent 67.It Va dev.hwpstate_intel.%d.%desc 68Describes the attached driver 69.It dev.hwpstate_intel.0.%desc: Intel Speed Shift 70.It Va dev.hwpstate_intel.%d.%driver 71Driver in use, always hwpstate_intel. 72.It dev.hwpstate_intel.0.%driver: hwpstate_intel 73.It Va dev.hwpstate_intel.%d.%parent 74The CPU that is exposing these frequencies. 75For example 76.Va cpu0 . 77.It dev.hwpstate_intel.0.%parent: cpu0 78.It Va dev.hwpstate_intel.%d.epp 79Energy/Performance Preference. 80Valid values range from 0 to 100. 81Setting this field conveys a hint to the hardware regarding a preference towards 82performance (at value 0), energy efficiency (at value 100), or somewhere in 83between. 84.It dev.hwpstate_intel.0.epp: 0 85.El 86.Sh COMPATIBILITY 87.Nm 88is only found on supported Intel CPUs. 89.Sh SEE ALSO 90.Xr cpufreq 4 91.Rs 92.%T "Intel 64 and IA-32 Architectures Software Developer Manuals" 93.%U "http://www.intel.com/content/www/us/en/processors/architectures-software-developer-manuals.html" 94.Re 95.Sh AUTHORS 96This manual page was written by 97.An D Scott Phillips Aq Mt scottph@FreeBSD.org . 98