hw.ncpu changes after recent updates

Antranig Vartanian antranigv at freebsd.am
Thu Jun 27 14:57:27 UTC 2019

Hi J.

Hyper-Threading[1] is a technology which allows running two threads on one
core, however since Intel had multiple security issues, many people have
turned it off, not sure you did that manually or has been changed during an

so yes, if you had ncpu=8 before, now it should be 4 :)

1: https://en.m.wikipedia.org/wiki/Hyper-threading

On Thu, Jun 27, 2019, 6:31 PM tech-lists <tech-lists at zyxst.net> wrote:

> Hi,
> Possibly a silly question, but is it expected that hw.ncpu would change
> after the recent intel cpu related updates?
> hw.ncpu used to be 8, is now 4. CPU is i7-4770K
> machdep.hyperthreading_allowed=0
> thanks,
> --
> J.

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