[ltp] Question on APM vs ACPI

[Nathan Kurz]

On Tue, Dec 07, 2004 at 10:26:07PM -0600, Brian D. Ropers-Huilman wrote:
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> Nathan Kurz said the following on 2004-12-07 21:38:
> | On Tue, Dec 07, 2004 at 07:50:59AM +0100, Bob Alexander wrote:
> |>2) ACPI is much better on CPU throttling (ala SpeedStep) when running on
> |>battery
> |
> | I'm trying to understand this myself.  It seems that throttling is
> | only possible under ACPI, but that frequency scaling is independent of
> | APM/ACPI.  It also seems that scaling has a much larger effect than
> | throttling on power consumption.  My impression is that SpeedStep is
> | the combination of these two.  Is this accurate?
> 
> What do you mean by throttling? As I understand it, throttling is merely
> dynamically changing CPU frequency, which is really just frequency
> scaling with automatic controls. cpudyn is described as, "A daemon to
> control laptop power consumption via cpufreq and disk standby." cpufreq
> says, "Daemon to adjust CPU speed for power saving." speedfreq is a
> "daemon to control the CPU speed in 2.6 kernels"

I think throttling is something that can be done in addition to that:
 http://acpi.sourceforge.net/documentation/processor.html (bottom of page)
But I don't understand it well, which is why I'm asking questions...

--nate