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    SubjectRe: Clock running at half speed in 2.6.20?
    On Fri, 2007-02-16 at 22:28 +0800, Adam J. Richter wrote:
    > My system clock runs at approximately half speed in
    > linux-2.6.20, 2.6.20-git10 and 2.6.20-git11. That is, it takes about
    > two hours for "date" to report that one hour has elapsed. "hwclock"
    > returns the correct time, of course.
    > I do not have this problem in linuux I will try to
    > narrow down the kernel version where this problem began.
    > The motherboard in question is an asus p4v8000-x, running a
    > 2.8GHz Pentium 4 that has two hyperthreads, which I suspect may be the
    > problem. I am just guessing, but perhaps some piece of code thinks
    > the two hyperthreads are separate CPU's receving twice as many clock
    > interrupts total. I expect to try to some experimentation to check
    > this theory.
    > For what it's worth, I am running CONFIG_PREEMPT=y,

    if you run,

    cat /sys/devices/system/clocksource/clocksource0/current_clocksource

    it will tell you which hardware clock is being used by the kernel. You
    can also run,

    cat /sys/devices/system/clocksource/clocksource0/available_clocksource

    which will tell you which clocks are available on your system. You
    switch clocks by echoing the name of a clock into "current_clocksource"

    As an example, the following switches to the acpi_pm clocksource,

    echo "acpi_pm"> /sys/devices/system/clocksource/clocksource0/current_clocksource

    The hardware clock that your using could be running to slow. I would
    recommend switching the hardware clock and re-check if the time is still
    half speed.


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      Last update: 2007-02-16 17:29    [W:0.020 / U:34.396 seconds]
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