EST(4) FreeBSD Kernel Interfaces Manual EST(4)
NAME
est - Enhanced Speedstep Technology
SYNOPSIS
To compile this capability into your kernel place the following line in
your kernel configuration file:
device cpufreq
DESCRIPTION
The est interface provides support for the Intel Enhanced Speedstep
Technology.
Note that est capabilities are automatically loaded by the cpufreq(4)
driver.
LOADER TUNABLES
The est interface is intended to allow cpufreq(4) to access and implement
Intel Enhanced SpeedStep Technology via acpi(4) and the acpi_perf
interface accessors. If the default settings are not optimal, the
following sysctls can be used to modify or monitor est behavior.
hw.est.msr_info
Attempt to infer information from direct probing of the msr.
Should only be used in diagnostic cases. (default 0)
hw.est.strict
Validate frequency requested is accepted by the CPU when set. It
appears that this will only work on single core cpus. (default
0)
SYSCTL VARIABLES
The following sysctl(8) values are available
dev.est.%d.%desc
Description of support, almost always Enhanced SpeedStep
Frequency Control.
dev.est.0.%desc: Enhanced SpeedStep Frequency Control
dev.est.%d.%driver
Driver in use, always est.
dev.est.0.%driver: est
dev.est.%d.%parent
The CPU that is exposing these frequencies. For example cpu0.
dev.est.0.%parent: cpu0
dev.est.%d.freq_settings.
The valid frequencies that are allowed by this CPU and their step
values.
dev.est.0.freq_settings: 2201/45000 2200/45000 2000/39581 1900/37387
1800/34806 1700/32703 1600/30227 1500/28212 1400/25828 1300/23900
1200/21613 1100/19775 1000/17582 900/15437 800/13723
DIAGNOSTICS
est%d: <Enhanced SpeedStep Frequency Control> on cpu%d
Indicates normal startup of this interface.
est: CPU supports Enhanced Speedstep, but is not recognized.
est: cpu_vendor GenuineIntel, msr 471c471c0600471c
device_attach: est%d attach returned 6
Indicates all attempts to attach to this interface have failed. This
usually indicates an improper BIOS setting restricting O/S control of the
CPU speeds. Consult your BIOS documentation for more details.
COMPATIBILITY
est is only found on supported Intel CPUs.
SEE ALSO
cpufreq(4)
Intel 64 and IA-32 Architectures Software Developer Manuals,
http://www.intel.com/content/www/us/en/processors/architectures-software-developer-manuals.html.
AUTHORS
This manual page was written by Sean Bruno <
[email protected]>.
FreeBSD 14.1-RELEASE-p8 April 21, 2020 FreeBSD 14.1-RELEASE-p8