Messages in this thread | | | Subject | Re: Clock running at half speed in 2.6.20? | From | Daniel Walker <> | Date | Fri, 16 Feb 2007 08:24:54 -0800 |
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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 2.6.18.1. 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, > CONFIG_PREEMPT_BKL=y, CONFIG_HZ=1000.
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.
Daniel
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