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), odcm(4), 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 ichlpcib(4) or piixpcib(4) provide support for SpeedStep, the PCI-based interfaces should not be accessed due possible race conditions.