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    SubjectRe: [RFC PATCH v2 0/2] sched: Nominate a power-efficient ILB
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    On Mon, 2009-04-13 at 21:55 -0700, Gautham R Shenoy wrote:
    > Now, the other power-savings settings such as the sched_mc/smt_power_savings
    > and the power-aware IRQ balancer try to balance tasks/IRQs by taking
    > the system topology into consideration, with the intention of keeping
    > as many "power-domains" (cores/packages) in the low-power state.
    >
    > The current idle-load-balancer nomination does not necessarily align towards
    > this policy. For eg, we could be having tasks and interrupts largely running
    > on the first package with the intention of keeping the second package idle.
    > Hence, CPU 0 may be busy. The first_cpu in the nohz.cpu_mask happens to be CPU1,
    > which in-turn becomes nominated as the idle-load balancer. CPU1 being from
    > the 2nd package, would in turn prevent the 2nd package from going into a
    > deeper sleep state.
    >
    > Instead the role of the idle-load balancer could have been assumed by an
    > idle CPU from the first package, thereby helping the second package go
    > completely idle.

    Can we also do this by default? i.e., even when no power-savings policy
    is selected.

    I don't see anything wrong by enabling this logic for all the cases.

    thanks,
    suresh



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