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    SubjectRe: [PATCH] optional non-interactive mode for cpu scheduler

    * Con Kolivas <> wrote:

    > I'll look into coding it later this week (thanks for suggesting I do
    > it btw). This ordeal has left me seriously sleep deprived :P


    > Since we're considering providing a special cpu policy for high
    > latency high cpu usage, does that mean we can now talk about other
    > policies like batch, isochronous etc? And in the medium to long term
    > future, gang and group?

    SCHED_ISO would be interesting, but all SCHED_BATCH patches that i've
    seen so far were fundamentally broken. [ none protects against the
    possibility of a simple CPU hog starving a SCHED_BATCH task in kernel
    mode holding say /home's i_sem forever. None except the one i wrote a
    couple of years ago that is ;-) ]

    but obviously any new scheduling policy first needs considerable
    testing, exposure and concensus. The main thing that makes
    SCHED_CPUBOUND possibly objectionable is that it could easily be used as
    a flag to 'turn off the interactivity code', which is wrong and just
    prolongs the fixing of interactivity-estimator bugs. Scientific apps
    burn CPU time exclusively and they have a stable priority at the low end
    of the range.

    One exception would be CPU-bound code with multiple threads which
    interact with each other - one always runs but the others always sleep.
    A possible solution would be to exclude all inter-task synchronization
    methods from the 'interactivity boost' and only hard-device-waits would
    be considered true 'waiting', such as keyboard, mouse, disk or network

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