cpu - Central Processing Unit
Several processor models have additional features that extend their base
functionality, such as power and frequency control or additional instructions.
The sysctl(3) hw.cpuspeed will return the current operating
the processor. If possible, speed may be adjusted by altering hw.setperf
from 0 to 100, representing percentage of maximum speed.
There are several
possible implementations for setperf, all transparent
to the user.
In systems with more than one control capability, they are
the order given.
LongRun Found on Transmeta Crusoe processors, offers
with numerous positions. The processor dynamically adjusts
frequency in response to load, the setperf
value is interpreted
as the maximum.
EST Enhanced SpeedStep found on Intel Pentium M processors, offers
frequency scaling with numerous positions.
SpeedStep Found on some Intel Pentium 3 and newer mobile
chips, it is
capable of adjusting frequency between a low and
Only enabled on some chipsets.
TCC Thermal Control Circuit found on Intel Pentium 4
processors, adjusts processor duty cycle in 12.5
PowerNow Found on various AMD processors. Currently only
some models in the K6 family.
INSTRUCTION SET EXTENSIONS [Toc] [Back]
The presence of extended instruction sets can be determined
osfxsr Supports the fxsave instruction.
sse Supports the SSE instruction set.
sse2 Supports the SSE2 instruction set.
xcrypt Support the VIA AES encryption instruction set.
If this is
supported, the libcrypto EVP AES functions will
use this support.
ichpcib(4), npx(4), sysctl(8)
OpenBSD 3.6 March 15, 2004
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