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    SubjectRe: [RFC PATCH v2 3/5] futex: Throughput-optimized (TO) futexes
    On 09/22/2016 05:41 PM, Thomas Gleixner wrote:
    > On Thu, 22 Sep 2016, Davidlohr Bueso wrote:
    >> On Thu, 22 Sep 2016, Waiman Long wrote:
    >>
    >>> BTW, my initial attempt for the new futex was to use the same workflow as
    >>> the PI futexes, but use mutex which has optimistic spinning instead of
    >>> rt_mutex.
    >> Btw, Thomas, do you still have any interest pursuing this for rtmutexes from
    >> -rt into mainline? If so I can resend the patches from a while ago.
    > Certainly yes. My faint memory tells me that there was some potential issue
    > due to boosting the owner only if it gets scheduled out, but I might be
    > wrong.

    It is tricky to add optimistic spinning to rtmutexes because of the need
    to observe process priorities. It is certainly possible to make the top
    waiter spin, but then I am not sure how much performance gain with just
    that.

    Cheers,
    Longman

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