On Wed, Feb 01, 2023 at 07:35:16AM +0100, Janne Johansson wrote:
> Den ons 1 feb. 2023 kl 03:08 skrev Justin Muir <ve7...@gmail.com>:
> > I've got an AMD A10 with 4 cores and only 2 are online. I'm not sure how to
> > enable the other 2.
> >
> > hw.ncpufound=4 btw
> > Any ideas out there?
>
> OpenBSD disables hyperthreading (or symmetric multithreading, smt), so
> if your "4-core" cpu is actually 2 real cores and 2 hyperthreads, then
> this sounds perfectly reasonable.
>
> For example, this box of mine (not the same cpu, but still), it looks like
> this:
>
> hw.ncpufound=8
> hw.smt=0
> hw.ncpuonline=4
>
> so I get the 4 real cores running out of possibly 8.
>
> --
> May the most significant bit of your life be positive.
>
It is posible to enable symmetric multithreading, at your own risk as
it makes certain types of attack easier. Often it does not increase
performance.
sysctl hw.smt=1
See man sysctl.conf for a permanent solution.
-Otto
