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    SubjectRe: cpuidle asymmetry (was Re: [RFC PATCH V4 5/5] cpuidle: cpuidle driver for apm)
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    On Fri, 2011-04-01 at 00:09 -0400, Len Brown wrote:
    > > > Moorestown is already an example of an asymmetric system,
    > > > since its deepest c-state is available on cpu0, but not on cpu1.
    > > > So it needs different tables for each cpu.
    > >
    > > wtf are these hardware guys smoking and how the heck are we supposed to
    > > schedule on such a machine? Prefer to keep cpu1 busy while idling cpu0?
    >
    > they are smoking micro-amps:-)

    Has anybody told them that pushing lots of logic into software generally
    burns more amps because it keeps the thing running longer?

    > S0i3 on cpu0 can be entered only after cpu1 is already off-line,
    > among other system hardware dependencies...
    >
    > So it makes no sense to export S0i3 as a c-state on cpu1.
    >
    > When cpu1 is online, the scheduler treats it as a normal SMP.

    Dipankar's reply seems to address this issue well.


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