Messages in this thread | | | Date | Mon, 13 Feb 2012 18:30:33 -0500 | From | Len Brown <> | Subject | Re: [PATCH 4/5] ACPI: Do cpufreq clamping for throttling per package v2 |
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On 02/06/2012 11:31 AM, Matthew Garrett wrote:
> On Mon, Feb 06, 2012 at 08:17:11AM -0800, Andi Kleen wrote: >> +#define reduction_pctg(cpu) \ >> + per_cpu(cpufreq_thermal_reduction_pctg, phys_package_first_cpu(cpu)) > > I don't like using percentages here - we end up with the potential for > several percentages to end up mapping to the same P state.
Does it matter?
> I've sent a
> patch that replaces the percentage code with just stepping through P > states instead. But otherwise, yes, this seems sensible. An open > question is whether we should be doing the same on _PPC notifications. > There's some vague evidence that Windows does.
If you stepped by P-states, then you behave entirely differently on a machine with many P-states vs a machine with few P-states.
There is code floating about that exposes every 100 MHz step on SNB and later as a P-state -- you can have quite a few...
thanks, -Len Brown, Intel Open Source Technology Center
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