Date: Tue, 13 Jul 2021 15:00:08 -0400 From: Paul Procacci <pprocacci@gmail.com> To: "Thomas D. Dean" <tomdean@wavecable.com> Cc: FreeBSD Questions <freebsd-questions@freebsd.org> Subject: Re: How do I disable CPU throttling Message-ID: <CAFbbPuimOGz41YX89Opf4O=10E5EnbVt%2BgbeHd57yFi_bS=8Cg@mail.gmail.com> In-Reply-To: <48605aef-d1ba-c24a-bae7-cb69306410a8@wavecable.com> References: <f982b8fd-0ec0-24a9-8272-4da3bd5d19c4@wavecable.com> <0be4883a-6bf6-28bc-a14b-9cb1f6d729ae@wavecable.com> <CAFbbPuhuWdzjfH2e7RSwiUa2UORAoJE_-yQeqyoMz7gTMjfxTA@mail.gmail.com> <4d1e32fc-3e77-626e-138b-6af872445c5e@wavecable.com> <CAFbbPuh5aCUF_07y-fiyg7kxRxSOCNQHAtSTDPQYrZQpA4HsOQ@mail.gmail.com> <48605aef-d1ba-c24a-bae7-cb69306410a8@wavecable.com>
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On Tue, Jul 13, 2021 at 12:56 AM Thomas D. Dean <tomdean@wavecable.com> wrote: > On 7/12/21 8:17 PM, Paul Procacci wrote: > > > > > sysctl dev.cpu.0 | grep freq > dev.cpu.0.freq_levels: 3700/4070 2800/2800 2200/1980 > dev.cpu.0.freq: 2200 > > These numbers are in GHz. > > What I want to do is understand where the numbers 3700 and 4070 come from. > > You aren't looking at the right place. This information is offered by the CPU and it's the CPU's documentation that you'll find the information you're looking for. If using Intel for instance, you'd be interested in reading about SpeedStep. Along with that, you'll want to understand ACPI, which is essentially the software side, or programmable interface to SpeedStep among other things. For instance, bit 22 in edx after a `cpuid` instruction with eax set to 0x01 will tell ya if if the cpu even supports acpi. ~Paul
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