Kernel forces machdep.hlt_cpus, how to change?

Colin Percival cperciva at
Thu Jan 5 09:49:07 PST 2006

Walter Hop wrote:
> I'm  testing  out  FreeBSD  6.0R  on  a  Dual  Xeon. I want to do some
> benchmarking  of hyperthreading before I put this machine into use, so
> I am trying to turn off the HLTing of logical cpu's.

Read FreeBSD-SA-05:09.htt :

and then, if you don't have any local untrusted users, consider setting
machdep.hyperthreading_allowed=1 in /boot/loader.conf.

Colin Percival

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