How do I turn off hyperthreading on 6.0 ?
Pete French
petefrench at ticketswitch.com
Fri Jan 27 11:24:20 PST 2006
> Disable it in the BIOS. The kernel can't use what isn't advertised as
> available. :)
true - but surely this is a bug in FreeBSD ?
man smp says:
"Since using logical CPUs can cause performance penalties under certain
loads, the logical CPUs can be disabled by setting the
machdep.hlt_logical_cpus sysctl to one."
I have:
websvr04# sysctl machdep.hlt_logical_cpus
machdep.hlt_logical_cpus: 1
but I am still seeing 4 CPU's as I have two physical processors, each with
two logical ones onboard.
I find it very hard to believe theres a bug in something this basic though,
as it's specificly mentioned in the relase notes as being there to disable
hyperthreading...
very odd...
-pete.
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