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    SubjectRe: [PATCH v1 00/10] Optimize sched avgs computation and implement flat util hierarchy
    On Tue, Aug 23, 2016 at 03:28:19PM +0200, Vincent Guittot wrote:
    > I still wonder if using a flat util hierarchy is the right solution to
    > solve this problem with utilization and task group. I have noticed
    > exact same issues with load that generates weird task placement
    > decision and i think that we should probably try to solve both wrong
    > behavior with same mechanism. but this is not possible with flat
    > hierarchy for load
    >
    > Let me take an example.
    > TA is a always running task on CPU1 in group /root/level1/
    > TB wakes up on CPU0 and moves TA into group /root/level2/
    > Even if TA stays on CPU1, runnable_load_avg of CPU1 root cfs rq will become 0.

    Because while we migrate the load_avg on /root/level2, we do not
    propagate the load_avg up the hierarchy?

    And always propagating everyrthing up will indeed also fix the
    utilization issue.

    Of course, doing that propagation has its costs..

    Didn't you post a patch doing just this a while ago?

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