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    SubjectRe: [PATCH] amd76x_pm on 2.6.0-test9 cleanup
    From
    On Tuesday, November 4, 2003, at 03:05 PM, Tony Lindgren wrote:

    > * Charles Lepple <clepple@ghz.cc> [031104 11:45]:
    >> On Tuesday 04 November 2003 02:15 pm, Tony Lindgren wrote:
    >>> I've heard of timing problems if it's compiled in, but supposedly
    >>> they
    >>> don't happen when loaded as module.
    >>
    >> In some of the earlier testX versions of the kernel, I did not see any
    >> difference between compiling as a module, and compiling into the
    >> kernel. (It
    >> is currently a module on my system.)
    >>
    >> I did, however, manage to keep ntpd happy by reducing HZ to 100. Even
    >> raising
    >> HZ to 200 is enough to throw off its PLL. The machine is idle for 90%
    >> of the
    >> day, though, so I don't know if the PLL is adapting to the fact that
    >> the
    >> system is idling, but the values for tick look reasonable.
    >
    > Interesting, sounds like the idling causes missed timer interrupts?
    > Can you
    > briefly describe what's the easiest way to reproduce the timer
    > problem, just
    > change HZ to 200 and look at the system time?

    Weird. On -test9-bk at HZ=1000, with amd76x_pm loaded as a module
    (lazy_idle=800, the default), the system clock is running fast.

    With ntpd running, the clock was stepped back 2.5 seconds twice in 20
    minutes.

    Here's what I get from adjtimexconfig (after stopping ntpd, of course):

    # adjtimexconfig
    Comparing clocks (this will take 70 sec)... adjusting system time by
    -126.211 sec/day
    Done

    Now tick is 9985. I distinctly remember it being somewhat over 10,000
    the last time I ran with HZ=1000 and amd_76x_pm active. With HZ=100,
    adjtimexconfig sets tick=10002.

    I'm not entirely sure what the "acpi" interrupt is doing-- it
    increments about once every two seconds when the system is idle, and
    various types of system activity make it happen more frequently. At
    least I'm not getting any "irq 9: nobody cared!" messages anymore (the
    button module is loaded, so I guess it is handling it). If I don't have
    amd76x_pm loaded, the acpi interrupt is triggered a couple of times
    after button is loaded, but then it doesn't happen again until I
    actually press a button.

    --
    Charles Lepple
    ghz.cc! clepple

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