Re: [RFC v1] Tunable sched_mc_power_savings=n

On Sat, Jun 28, 2008 at 02:36:02PM +0200, Andi Kleen wrote:

For example if you're in a data center at a specific operating point and
you would need to crank up the air condition at significant power cost it might
be well better overall to force all servers to a lower operating point
and avoid that.

Sure, there are cases where you have additional constraints. But within
those constraints, you probably want to run as fast as possible.

That said in general you all should have complained when ondemand behaviour
was introduced.

ignore_nice seems to be set to 0 by default?

Also it's unclear that the general "race to idle" heuristic really
applies to the case of the "keep sockets idle" power optimization
that started this thread.

Usually package C states bring much more than core C states
and keeping another package completely idle saves likely
more power than the power cost of running something a little
bit slower on a package that is already busy on another core.

I'd agree with that.
--
Matthew Garrett | mjg59@xxxxxxxxxxxxx
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