the clock stopped in F7 ?!

[Mike]

On Mon, 27 Aug 2007, Lonni J Friedman wrote:

>
> The timer in /proc/interrupts was not changing, and neither was the
> timestamp in /proc/schedstat.  ugh.
>

Sorry for the confusion.  Andy Green's posts clear this up and hopefully 
this will clarify somewhat too.

For aeon's, well maybe centuries, ok really just decades the majority of 
OS'es that run on PC's used IRQ0 to update the real time clock.  What this 
means is that 100 times a second (100 Hz) the kernel (in the case of 
linux) is interrupted and the real time clock is updated among other 
things then the kernel goes about it's business.  To get better resolution 
the 100 Hz parameter is changeable at compile time to 100, 250 or 1000 (I 
believe).  I think it defaulted to 1000Hz recently.  In any case as Andy 
Green pointed out modern kernels have gone "tickless".  This is a very 
good thing for laptops and saving power etc.

>From what I have read HPET or High Precision Event Timer is what is used 
now (in the 2.6.21 or so kernel timeframe and beyond).  HPET is a device 
that is part of the chipsets on modern motherboards.  From what I've been 
told the HPET code is broken in some kernel versions (I mean hey it's 
brand new code, sure could be buggy).

So to the original poster (Lonni J Friedman?) I'd suggest (as Andy 
mentioned) check to see what your clocksource is:

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

If it says 'hpet' reboot your machine and pass 'hpet=disable' to the 
kernal via grub.  I don't have a machine that I can reboot at the moment, 
but IIRC at the grub prompt you press 'e' to edit the command before 
booting.  From there I forget but google should help find the syntax.  Or 
perhaps it's even self explanatory.

In any case this should force your machine to keep time the old fashioned 
way which unless you're on a laptop should be just fine.  And if this 
works you can edit grub.conf (I believe) and 'hpet=disable' to make this 
permanent.

-- Mike