Messages in this thread | | | Date | Tue, 04 Feb 2014 06:53:41 -0800 | From | Arjan van de Ven <> | Subject | Re: [RFC PATCH 3/3] idle: store the idle state index in the struct rq |
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> 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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