detecting hyperthreading

[Pokala, Ravi]

-----Original Message-----
From: Rui Paulo <rpaulo at me.com>
Date: 2015-03-09, Monday at 18:19
To: Ravi Pokala <rpokala at panasas.com>
Cc: "freebsd-hackers at freebsd.org" <freebsd-hackers at freebsd.org>
Subject: Re: detecting hyperthreading

>I think that sysctl didn't fully control hyperthreading: you can disable
>it on the BIOS and FreeBSD never exported that information.  If you used
>that tunable, it would simply disable the Pentium 4 Hyperthreading.

I never tried to *change* it at runtime; I just used it's *existence* as
an indicator that HT was enabled. (Aside - why did it not exist at all
when HT was disabled, as opposed to always existing and just having
zero/non-zero values?)

-Ravi

>--
>Rui Paulo