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    SubjectRe: [RFC] clocksouce implementation for powerpc
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    On Wed, Jun 20, 2007 at 07:57:19AM -0700, Daniel Walker wrote:

    Hi Daniel.

    > As I said in our private thread, I do think you should be using
    > update_vsyscall() .. update_vsyscall() is just called when the time is
    > set, usually that happens in the timer interrupt and sometimes that
    > happens in settimeofday() ..

    Well I've taken another look at the code and I think I can probably
    restructure my code to use update_vsyscall(). I thought I needed a
    hook that was called /only/ from settimeofday() (which as you say
    doesn't match update_vsyscall()'s usage).

    I'll try again and see what problems I hit.

    > At least some of your code is duplications over what is already being
    > worked on inside the powerpc community.. For instance, I know there is
    > already a timebase clocksource,
    >
    > http://people.redhat.com/~mingo/realtime-preempt/patch-2.6.21.5-rt17

    Thanks. The one in -rt doesn't seem to support the VDSO. however I see
    that there is duplication of effort there.

    > Hmm .. This doesn't look like it's taking into account that the time has
    > changed .. Your time has effectively incremented by one jiffie .. The
    > vdso_data doesn't appear to be updated ..

    Unless I miss your meaning, the vdso is updated in
    timer_recalc_offset()/update_gtod() when needed.

    Yours Tony

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