EST(4) | Device Drivers Manual (x86) | EST(4) |
est
—
est0 at cpu0
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.cpu.frequency.target
machdep.cpu.frequency.current
machdep.cpu.frequency.available
est
.Note, however, that these variables are not guaranteed to exist in the future versions of NetBSD.
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.
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.
September 7, 2020 | NetBSD 10.1 |