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    SubjectRe: + stupid-hack-to-make-mainline-build.patch added to -mm tree
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    On Tue, 2007-03-06 at 17:44 -0800, Dan Hecht wrote:
    > >>> 2) As I said above. The time accounting for virtualization needs to be
    > >>> fixed in a generic way.
    > >>>
    > >>> I'm not going to accept some weird hackery for virtualization, which is
    > >>> of exactly ZERO value for the kernel itself. Quite the contrary it will
    > >>> make the cleanup harder and introduce another hard to remove thing,
    > >>> which will in the worst case last for ever.
    > >>>
    > >> Okay, to confirm I'm on the same page as you, you want to move process
    > >> time accounting from being periodic sampled based to being trace based?
    > >> i.e. at the system-call/interrupt boundaries, read clocksource and
    > >> compute directly the amount of system/user/process time?
    > >
    > > At least for the paravirt guests this is the correct approach. Once the
    > > CPU vendors come up with a sane solution for a reliable and fast clock
    > > source we might use that on real hardware as well.
    > >
    >
    > I thought your preference was to not do things differently from real
    > hardware? I guess this case you are okay with since you'd like to see
    > the real hardware case follow eventually?

    Real hardware _IS_ broken and slow. If we add the facilities for
    virtualization we want it in a way, which is usable by real hardware as
    well.

    > > Yes, with todays hardware it is simply a PITA. PowerPC has some basic
    > > support for this though, IIRC.
    > >
    >
    > I think S390 maybe too.

    One more reason to make it a generic solution rather than some extra
    hackery.

    tglx


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