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    SubjectRe: [PATCH 1/2] sched/fair: move cpufreq hook to update_cfs_rq_load_avg()
    On 30 March 2016 at 21:35, Peter Zijlstra <peterz@infradead.org> wrote:
    > On Mon, Mar 28, 2016 at 12:38:26PM -0700, Steve Muckle wrote:
    >> Without covering all the paths where CFS utilization changes it's
    >> possible to have to wait up to a tick to act on some changes, since the
    >> tick is the only guaranteed regularly-occurring instance of the hook.
    >> That's an unacceptable amount of latency IMO...
    >
    > Note that even with your patches that might still be the case. Remote
    > wakeups might not happen on the destination CPU at all, so it might not
    > be until the next tick (which always happens locally) that we'll
    > 'observe' the utilization change brought with the wakeups.
    >
    > We could force all the remote wakeups to IPI the destination CPU, but
    > that comes at a significant performance cost.

    Isn't a reschedule ipi already sent in this case ?

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