1.\" 2.\" Copyright (c) 2015 The DragonFly Project. All rights reserved. 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.\" 8.\" 1. Redistributions of source code must retain the above copyright 9.\" notice, this list of conditions and the following disclaimer. 10.\" 2. Redistributions in binary form must reproduce the above copyright 11.\" notice, this list of conditions and the following disclaimer in 12.\" the documentation and/or other materials provided with the 13.\" distribution. 14.\" 3. Neither the name of The DragonFly Project nor the names of its 15.\" contributors may be used to endorse or promote products derived 16.\" from this software without specific, prior written permission. 17.\" 18.\" THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS 19.\" ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 20.\" LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS 21.\" FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE 22.\" COPYRIGHT HOLDERS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, 23.\" INCIDENTAL, SPECIAL, EXEMPLARY OR CONSEQUENTIAL DAMAGES (INCLUDING, 24.\" BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; 25.\" LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED 26.\" AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, 27.\" OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT 28.\" OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 29.\" SUCH DAMAGE. 30.\" 31.Dd July 11, 2015 32.Dt APERF 4 33.Os 34.Sh NAME 35.Nm aperf 36.Nd driver measuring effective CPU frequency via APERF/MPERF MSRs 37.Sh SYNOPSIS 38To compile this driver into the kernel, 39place the following lines in your kernel configuration file: 40.Bd -ragged -offset indent 41.Cd "device aperf" 42.Ed 43.Pp 44Alternatively, to load the driver as a 45module at boot time, place the following line in 46.Xr loader.conf 5 : 47.Bd -literal -offset indent 48aperf_load="YES" 49.Ed 50.Sh DESCRIPTION 51The 52.Nm 53driver provides support for measuring the effective CPU frequency, using the 54APERF and MPERF MSRs. 55The values are exposed through the 56.Dv HW_SENSORS 57.Xr sysctl 3 58tree. 59For example: 60.Bd -literal -offset indent 61% sysctl hw.sensors 62hw.sensors.cpu0.freq0: 2684298000 Hz (cpu0 freq) 63hw.sensors.cpu1.freq0: 1418960000 Hz (cpu1 freq) 64hw.sensors.cpu2.freq0: 1234898000 Hz (cpu2 freq) 65hw.sensors.cpu3.freq0: 1242533000 Hz (cpu3 freq) 66.Ed 67.Sh HARDWARE 68The 69.Nm 70driver supports all AMD and Intel CPUs which provide the APERF and MPERF MSRs: 71.Pp 72.Bl -bullet -compact 73.It 74Most AMD CPUs starting at Family 10h 75.It 76Most Intel CPUs starting from Core series and Atom respectively. 77.El 78.Sh SEE ALSO 79.Xr systat 1 , 80.Xr sysctl 3 , 81.Xr sensorsd 8 , 82.Xr sysctl 8 83.Sh HISTORY 84The 85.Nm 86driver first appeared in 87.Dx 4.3 . 88.Sh AUTHORS 89.An -nosplit 90The 91.Nm 92driver was written by 93.An Imre Vadasz Aq Mt imre@vdsz.com . 94