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    SubjectRe: [RFC] [PATCH 0/3] Add group fairness to CFS
    On Wed, May 23, 2007 at 08:32:52PM +0200, Ingo Molnar wrote:
    > > Here's an attempt to extend CFS (v13) to be fair at a group level,
    > > rather than just at task level. The patch is in a very premature state
    > > (passes simple tests, smp load balance not supported yet) at this
    > > point. I am sending it out early to know if this is a good direction
    > > to proceed.
    > cool patch! :-)


    > > 1. This patch reuses CFS core to achieve fairness at group level also.
    > >
    > > To make this possible, CFS core has been abstracted to deal with
    > > generic schedulable "entities" (tasks, users etc).
    > yeah, i like this alot.
    > The "struct sched_entity" abstraction looks very clean, and that's the
    > main thing that matters: it allows for a design that will only cost us
    > performance if group scheduling is desired.
    > If you could do a -v14 port and at least add minimal SMP support: i.e.
    > it shouldnt crash on SMP, but otherwise no extra load-balancing logic is
    > needed for the first cut - then i could try to pick all these core
    > changes up for -v15. (I'll let you know about any other thoughts/details
    > when i do the integration.)

    Sure ..I will work on a -v14 port. I would like to target for something which:

    1. doesn't break performance/functionality of existing CFS scheduler
    -if- CONFIG_FAIR_USER_SCHEDULER is disabled. This also means load
    balance should work as it works today when the config option is

    Do you recommend a set of tests that I need to run to ensure there
    is no regression? I know that there is a bunch of scheduler
    tests floating around on lkml ..Just need to dig to them (or if
    someone has all these tests handy on a website, I will download from
    that site!)

    2. Provides fairness at group (user) level at the cost of missing load
    balance functionaility (missing until I get around to work on it that

    > kernel builds dont really push scheduling micro-costs, rather try
    > something like 'hackbench.c' to measure that. (kernel builds are of
    > course one of our primary benchmarks.)

    sure i will try that on my next version.

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