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)

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 <sbruno@FreeBSD.org>.