Re: Disabling CPUs
- Reply: Kevin Oberman : "Re: Disabling CPUs"
- In reply to: Kevin Oberman : "Disabling CPUs"
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Date: Thu, 22 Sep 2022 02:26:31 UTC
(Resending with list included) Hey Keith, Taken from smp(4): FreeBSD allows specific CPUs on a multi-processor system to be disabled. This can be done using the hint.lapic.X.disabled tunable, where X is the APIC ID of a CPU. Setting this tunable to 1 will result in the corresponding CPU being disabled. smp(4) further describes how to detect CPU topologies and whatnot. Specifically the following sysctl seems useful: kern.sched.topology_spec Though I'm not entirely sure, I'd personally start with the above. ~Paul On Wed, Sep 21, 2022 at 10:06 PM Kevin Oberman <rkoberman@gmail.com> 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. > -- > Kevin Oberman, Part time kid herder and retired Network Engineer > E-mail: rkoberman@gmail.com > PGP Fingerprint: D03FB98AFA78E3B78C1694B318AB39EF1B055683 > -- __________________ :(){ :|:& };: