Re: Disabling CPUs

Thanks, Amar! I'll give this a try tomorrow.

Have you compared performance using only P cores vs. only E cores? My
testing (using only cpuset) compiles C faster with 8 E cores than 2 P cores
(4 "CPUs").

By any chance have you run a VirtualBox VM? I have found that a Windows 10
VM loads, but the system panics as soon as the VM starts running. I have a
couple of things to try that could be triggering the problem. Notably, I
have 3D HW acceleration enabled and, since it is not available with scfb,
it's a possible cause.

I'm getting tired of trailblazing! My current laptop did not have a working
Wii interface until iwlwifi. I had een almost no comments on CURRENT, soi I
had no idea how much trouble I was gettig into.

On Thu, Sep 22, 2022 at 11:06 AM Amar Takhar <verm@darkbeer.org> wrote:

> On 2022-09-21 19:05 -0700, Kevin Oberman wrote:
> > I am looking to disable all 8 E-cores on my Alder Lake system to prevent
> > repeated crashes. The man page has an example of this:
> > Modify the cpuset all threads are in by default to contain only the
> first 4
> > CPUs, leaving the rest idle:
> >            cpuset -l 0-3 -s 1
> > I did this, but in subsequent port build, all 12 "CPUs" were running at
> 100%.
> > Am I missing something? Maybe use -p 1" instead of "-s 1".
> >
> > I also found suggestions to use "hint.lapic.N.disabled", but teh lines
> that
> > were supposed to be in dmesg and the messages log were not present. I am
> > baffled, but really need to do something to stop the crashes currently
> > impacting Alder Lake systems.
>
> You need to do it in BIOS it's the only way.  Unfortunately even if you do
> it
> within FreeBSD it still sees those cores just doesn't schedule them it
> causes an
> issue somewhere regardless I did try to not schedule anything to them.
>
> If you don't see any specific option to disable E-cores you'll need to
> disable
> them individually.  As far as I know the E-cores are always the last cores
> in
> the list.
>
> Any Alder Lake BIOS should have the setting.
>
>
> Amar.
>
>

-- 
Kevin Oberman, Part time kid herder and retired Network Engineer
E-mail: rkoberman@gmail.com
PGP Fingerprint: D03FB98AFA78E3B78C1694B318AB39EF1B055683