[Ukfreebsd] Disabling hyperthreading on Intel CPUs
andy at time-domain.co.uk
Wed Jan 26 08:34:17 GMT 2011
Dos anyone know what happned to the machdep.hyperthreading_allowed
tunable? It was definitely there in (I think) 5.x but in 8.1 it's not:
andy at dell380:~ $ sysctl machdep.hyperthreading_allowed=0
sysctl: unknown oid 'machdep.hyperthreading_allowed'
There are some new CPU sysctls in 8.x but they seem to disable cores
rather than hyperthreading, which is enabled by default in the kernel. I
would like to be able to turn off hyperthreading at runtime on a large
number of HP PCs that are fitted with single quad-core CPUs without
touching the BIO settings.
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