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    SubjectRe: [patch] CFS scheduler, -v8
    At some point in the past, Ting Yang wrote:
    >> Based on my understanding, adopting something like EEVDF in CFS should
    >> not be very difficult given their similarities, although I do not have
    >> any idea on how this impacts the load balancing for SMP. Does this worth
    >> a try?
    >> Sorry for such a long email :-)

    On Wed, May 02, 2007 at 11:42:20AM -0700, Li, Tong N wrote:
    > Thanks for the excellent explanation. I think EEVDF and many algs alike
    > assume global ordering of all tasks in the system (based on virtual
    > time), whereas CFS does so locally on each processor and relies on load
    > balancing to achieve fairness across processors. It'd achieve strong
    > fairness locally, but I'm not sure about its global fairness properties
    > in an MP environment. If ideally the total load weight on each processor
    > is always the same, then local fairness would imply global fairness, but
    > this is a bin packing problem and is intractable ...

    It's sort of obvious how to approximate it, but not entirely obvious
    whether a given approximation actually suffices. More help with the
    theoretical aspects is needed.


    - wli
    -
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