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    SubjectRe: [RFC PATCH 3/3] idle: store the idle state index in the struct rq

    * Peter Zijlstra <peterz@infradead.org> wrote:

    > [...]
    >
    > The reason Ingo took it out was that these measured numbers would
    > slightly vary from boot to boot making it hard to compare
    > performance numbers across boots.
    >
    > There's something to be said for either case I suppose.

    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.

    Thanks,

    Ingo


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