Skip site navigation (1)Skip section navigation (2)

FreeBSD Man Pages

Man Page or Keyword Search:
Man Architecture
Apropos Keyword Search (all sections) Output format
home | help
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 Tech-
     nology.

     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 inter-
     face 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 Fre-
	     quency 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

     dev.est.0.%parent:	cpu0
	     The cpu that is exposing these frequencies.  For example 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	<sbruno@FreeBSD.org>.

FreeBSD	10.1		       October 18, 2012			  FreeBSD 10.1

NAME | SYNOPSIS | DESCRIPTION | LOADER TUNABLES | SYSCTL VARIABLES | DIAGNOSTICS | COMPATIBILITY | SEE ALSO | AUTHORS

Want to link to this manual page? Use this URL:
<http://www.freebsd.org/cgi/man.cgi?query=est&manpath=FreeBSD+10.1-RELEASE>

home | help