Re: 2.6.24-rc4-git5: Reported regressions from 2.6.23

From: Arjan van de Ven
Date: Mon Dec 10 2007 - 20:10:03 EST


On Tue, 11 Dec 2007 01:01:25 +0100
Guillaume Chazarain <guichaz@xxxxxxxx> wrote:

> Arjan van de Ven <arjan@xxxxxxxxxxxxx> wrote:
>
> > the frequency of both cores is the maximum of what linux sets each
> > core to;
>
> Do you mean that the cpufreq code can be confused about the actual
> frequency of the cores?

it means that cpufreq doesn't know the actual frequency (although bios sometimes tells us about the relationship, often the bios just lies through it's teeth); it only knows what it asks for, not what it gets. We know it'll get at least what it asks for, but it can get more than it asks for basically.

>That sounds like a big problem.

it'll get way worse going forward.
(but even on todays systems, the tsc no longer represents frequency, but is some fixed clock totally unrelated to cpu frequency)

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