Re: exposing FSB clock speed in /sys

[Andi Kleen]

> I am not interested in older processors, but I think for all recent Intel
> processors, there is a fairly simple algorithm to get the frequency using
> a couple of MSRs (including MSR_IA32_EBL_CR_POWERON or MSR_FSB_FREQ).

Hmm, maybe make it an own driver that creates the sysfs entries somewhere.
I don't think it's useful enough for the main kernel.

But what happens during power saving that may lower the frequency? 
Wouldn't you need update events for that? That might complicate it.

> 
> Don't we already have /sys entries that exits only for certain processors
> or platforms?

Yes.

> I think the Opteron have HYPERTRANSPORT-related events which could be used
> to obtain similar metrics.

Yes, but you usually don't need the frequency.

-Andi
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