NAME
est —
Enhanced SpeedStep
SYNOPSIS
est0 at cpu0
DESCRIPTION
Theest 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, http://download.intel.com/support/processors/mobile/pm/sb/25261203.pdf, March, 2004.
Intel Corporation, Enhanced Intel SpeedStep Technology for the Intel Pentium M Processor., White Paper, http://download.intel.com/design/network/papers/30117401.pdf, March, 2004.
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.