Paul de Weerd <we...@weirdnet.nl> wrote:
> A recent commit by Theo changed the hw.perfpolicy behavior to always
> run at full speed when AC power is on. This means that my workstation
> (and servers, once I upgrade them) now consumes significantly more
> power, even though they usually idle.
Did you measure how much more power?
You must measure, to make the claim.
The OptiPlex 9020 is a modern i7, approximately 4785T generation, and
these contain C states:
acpicpu0 at acpi0: C2(200@148 mwait.1@0x33), C1(1000@1 mwait.1), PSS
Which means when the idle loop calls the "mwait" instruction, the cpu
will 'instantly' slow down, until an interrupt happens. And thus, save
power. That is how modern cpus work.
You must back your claim up with power measurements.
> [weerd@pom] $ sysctl hw.{vendor,product,perfpolicy,setperf,cpuspeed}
> hw.vendor=Dell Inc.
> hw.product=OptiPlex 9020
> hw.perfpolicy=auto
> hw.setperf=100
> hw.cpuspeed=3401
>
> If I'd want to use the old behavior on "non laptop" systems, what
> would be the best approach to try to achieve that? I mean, I can
> revert the commit, but then I'm stuck with a frankenstein system.
>
> Would another "economy" perfpolicy be better, or would it make more
> sense to try to divine the type of system and adjust accordingly?
>From false premises straight to conclusions that we (OpenBSD) must do
something.
