Re: [RFC PATCH 3/3] idle: store the idle state index in the structrq

[Arjan van de Ven]

> Yeah, so we could put the parameters back by measuring it in
> user-space via a nice utility in tools/, and by matching it to
> relevant hardware signatures (CPU type and cache sizes), plus doing
> some defaults for when we don't have any signature... possibly based
> on a fuzzy search to find the 'closest' system in the table of
> constants.
>
> That would stabilize the boot-to-boot figures while still keeping most
> of the system specific-ness, in a maintainable fashion.
>
> The downside is that we'd have to continuously maintain a table of all
> this info, with new entries added when new CPUs are introduced on the
> market. That's an upside too, btw.

for bigger systems this will also depend on the chipset and even motherboard
since inter-CPU communication may go via a 3rd party chip and the speed of that
will depend on how far they are apart...

like a 32 socket machine it'll be very different from a 2 socket machine,
and from the 32 socket machine from another vendor


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