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Date:      Thu, 27 Jun 2019 18:57:12 +0400
From:      Antranig Vartanian <antranigv@freebsd.am>
To:        FreeBSD Questions <freebsd-questions@freebsd.org>
Subject:   Re: hw.ncpu changes after recent updates
Message-ID:  <CAN4C8SHKqK__wmo=keeXVRZxQkeSWY6wte=x9_Kfns1f4Tezhg@mail.gmail.com>
In-Reply-To: <20190627143034.GA9574@mon.zyxst.net>
References:  <20190627143034.GA9574@mon.zyxst.net>

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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
update.

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@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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