Re: 2.6.25.2 - Jiffies/Time jumping back and forth (Regereesion from 2.6.24)

Thomas Gleixner
2008-05-08T10:30:21Z

On Wed, 7 May 2008, Martin Knoblauch wrote:
> > no this looks different. As soon as the timesource is detected, I see non-zero
> > timestamps
> > in dmesg, but they look smaller and jump in both directions. And I have never
> > seen this before
> > 2.6.25.
> >
> > It actually might be a good idea to get the dmesg output from 2.6.24.
> >
> > Cheers
> > Martin
>
> interesting - maybe related to clocksources. The HPET seems to be detected later in 2.6.25:
>
> 2.6.24:
>
> [ 0.000000] Initializing CPU#0
> [ 0.000000] PID hash table entries: 4096 (order: 12, 32768 bytes)
> -->[ 0.000000] hpet clockevent registered
> -->[ 0.000000] TSC calibrated against HPET

> 2.6.25.2:
>
> [ 0.000000] Initializing CPU#0
> [ 0.000000] PID hash table entries: 4096 (order: 12, 32768 bytes)
> -->[ 0.000000] TSC calibrated against PM_TIMER

That's odd indeed. Is HPET not registered at all in 2.6.25 or does it just happen late ?

please provide the output of:
/sys/devices/system/clocksource/clocksource0/available_clocksource
/sys/devices/system/clocksource/clocksource0/current_clocksource

Thanks,
tglx