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    SubjectRe: [GIT PULL] omap changes for v2.6.39 merge window
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    On Mon, 2011-04-04 at 01:59 +0100, Arnd Bergmann wrote:
    > On Sunday 03 April 2011, Russell King - ARM Linux wrote:
    > > Then there's those which change the cs->read function pointer at runtime,
    ...
    > > and those which share that pointer with their sched_clock() implementation.
    >
    > Abstracting sched_clock() to be run-time selected is something that
    > needs to be taken care of. Maybe we could have a generic sched_clock
    > implementation that is written on top of clocksource instead of jiffies,
    > and always select that on architectures that have a decent clocksource.

    On Cortex-A15 with the virtualisation extensions and architected timers
    the clocksource is implemented using a physical counter (as we want
    wall-clock timing). But for sched_clock() we may want to use a virtual
    counter (which is basically an offset from the physical one, set by the
    hypervisor during guest OS switching). Marc already posted some patches
    for this.

    --
    Catalin




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