Date: Thu, 22 Sep 2022 18:06:26 +0000 From: Amar Takhar <verm@darkbeer.org> To: questions@freebsd.org Subject: Re: Disabling CPUs Message-ID: <20220922180626.GB79310@darkbeer.org> In-Reply-To: <CAN6yY1s=ds_=yWsEWtVfoXchD5XXqU5uPw6bdFNW%2BdaU6t491A@mail.gmail.com> References: <CAN6yY1s=ds_=yWsEWtVfoXchD5XXqU5uPw6bdFNW%2BdaU6t491A@mail.gmail.com>
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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.
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