On Sat, 08 Jun 2024 11:09:29 +0100, Omar Polo <o...@omarpolo.com> wrote: > > On 2024/06/08 10:09:07 +0100, Kirill A. Korinsky <kir...@korins.ky> wrote: > > On Sat, 08 Jun 2024 04:57:49 +0100, > > Gustavo Rios <rios.gust...@gmail.com> wrote: > > > > > > i have installed obsd on my dell notebook 8 cores processor. When i > > > execute > > > the top utility, it is showed the cores, from 0 (cpu0) to 7 (cpu7), but > > > cpu1 and cpu3 is not listed. What is the problem ? > > > > > > > A blind guess: sysctl hw.smt=1 may return your hypertreading cores. > > which is a very bad advice to give. There's a reason sysctl hw.smt=1 > defaults to that value. One should rather give a "blind guess" of "your > hyperthread cores are disabled by default" rather than give a bad advice > without explanation.
I'll make my advice cleaner, I defently mean that missed cores probably is disabled becuae it is hyperthreading ones which can be seen as offline in htop, or enable via sysctl. Also, I'd like to add that from security point of view SMT in general and hyperthreading as an example is very bad idea. Thus, here old but interesting results that enabling hyperthreading has negative effect on performance of have CPU used applications: https://web.archive.org/web/20220325090914/http://users.telenet.be/nicvroom/performanceP4.htm -- wbr, Kirill
