Re: [PATCH]new ACPI processor driver to force CPUs idle

Matthew Garrett
2009-06-26T19:49:15Z

On Fri, Jun 26, 2009 at 12:46:53PM -0400, Len Brown wrote:

> Low Frequency Mode (LFM), aka Pn - the deepest P-state,
> is the lowest energy/instruction because it is this highest
> frequency available at the lowest voltage that can still
> retire instructions.
>
> That is why it is the first method used -- it returns the
> highest power_savings/performance_impact.

For a straightforward workload on a dual package system, do you get more
performance from two packages running at their lowest P state or from
one package at its highest P state and a forced-idle package? Which
consumes more power?

--
Matthew Garrett | mjg59@srcf.ucam.org