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    SubjectRe: [RESEND PATCH v1 1/2] cpuidle: menu: Correct the criteria for stopping tick
    On Sun, Aug 12, 2018 at 6:07 PM <leo.yan@linaro.org> wrote:
    >
    > On Sun, Aug 12, 2018 at 01:12:41PM +0200, Rafael J. Wysocki wrote:
    > > On Fri, Aug 10, 2018 at 11:03 AM <leo.yan@linaro.org> wrote:

    [cut]

    > >
    > > Assuming shot noise wakeups, if
    > > drv->states[drv->state_count-1].target_residency is less than
    > > TICK_USEC, the tick will be stopped for CPUs more often on average
    > > with the patch applied (simply because the idle duration range for
    > > which it will not be stopped is narrower then).
    >
    > Yes, good point, so in the new approach I try to change the code
    > to compare with next tick delta rather than TICK_USEC, it can keeps
    > running tick for the tick with long expire time (similiar with
    > comparing with TICK_USEC) but we also can stop tick if the tick is likely
    > to break idle residency.

    We tried something similar and the results were not encouraging.
    Please see https://lore.kernel.org/lkml/079e16b6-2e04-2518-0553-66becab226a6@tu-dresden.de/

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