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    SubjectRe: [PATCH] clean up FIXME in do_timer_interrupt
    On Fri, 2005-03-04 at 12:58 -0800, George Anzinger wrote:
    > Lee Revell wrote:
    > > On Fri, 2005-03-04 at 02:28 -0800, George Anzinger wrote:
    > > The thing that brought this code to my attention is that with PREEMPT_RT
    > > this happens to be the longest non-preemptible code path in the kernel.
    > > On my 1.3 Ghz machine set_rtc_mmss takes about 50 usecs, combined with
    > > the rest of timer irq we end up disabling preemption for about 90 usecs.
    > > Unfortunately I don't have the trace anymore.
    > >
    > > Anyway the upshot is if we hung this off a timer it looks like we would
    > > improve the worst case latency with PREEMPT_RT by almost 50%. Unless
    > > there is some reason it has to be done synchronously of course.
    > Well, it does have to be done at the right WRT the second, but I suspect we can
    > hit that as well with a timer as it is hit now. Also, if we are _really_ off
    > the mark, this can be defered till the next second.

    Do you have a patch?

    Andrew merged my trivial patch to clean up the logic, but a real fix
    would be better.


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