EST(4)

NAME
est - Enhanced SpeedStep

SYNOPSIS
est0 at cpu0

DESCRIPTION
The est driver provides support for Enhanced SpeedStep introduced in Intel's first and second generation of Pentium M processors. The following sysctl(8) variables are available with est:

machdep.est.frequency.target
    The target frequency of the CPUs.

machdep.est.frequency.current
    The current frequency.

machdep.est.frequency.available
    The frequencies recognized by est.

Note, however, that these variables are not guaranteed to exist in the future versions of NetBSD.

SEE ALSO
acpicpu(4), x86/odcm(4), x86/powernow(4) Intel Corporation, Intel Pentium M Processor., Datasheet, March, 2004, http://download.intel.com/support/processors/mobile/pm/sb/25261203.pdf. Intel Corporation, Enhanced Intel SpeedStep Technology for the Intel Pentium M Processor., White Paper, March, 2004, http://download.intel.com/design/network/papers/30117401.pdf.

CAVEATS
The est driver is considered a legacy interface to be used only with old systems. It is known to be problematic with new CPUs. Furthermore, in the unlikely case where both est and x86/ichlpcib(4) or piixpcib(4) provide support for SpeedStep, the PCI-based interfaces should not be accessed due possible race conditions.