Timedirft between system clock and hwclock
Henry Ritzlmayr
fedora-list at rc0.at
Thu May 10 06:50:32 UTC 2007
Hi List,
I installed FC6 x86_64 on an ASUS P5B-VM DO.
After the installation I noticed a time drift of the system clock.
The hardware clock works fine and is almost accurate (~200ms per day
drift).
Right after a reboot the command "date; hwclock"
shows:
Do 10. Mai 08:12:38 CEST 2007
Do 10 Mai 2007 08:12:40 CEST -0.001189 seconds
The same command after 5 minutes shows:
Do 10. Mai 08:17:32 CEST 2007
Do 10 Mai 2007 08:17:39 CEST -0.001189 seconds
So the system clock is to slow for ~1 second per minute.
In /var/log/messages i can see an entry
... kernel: warning: many lost ticks.
If I leave the system up for a couple of hours I also get
... kernel: Your time source seems to be instable or some driver is
hogging interupts
... kernel: Falling back to HPET
The "fallback" doesn´t change the drift. It is still ~1 second per
minute. I even think (not knowing for 100%) that the fallback doesn´t
work because of missing available clock sources -> see below.
$ cat /sys/devices/system/clocksource/clocksource0/available_clocksource
jiffies
$ cat /sys/devices/system/clocksource/clocksource0/current_clocksource
jiffies
Then I tried booting in rescue mode with FC6 i386 and the system clock
is accurate here.
I also noticed that the available clock sources and the chosen one are
different.
$ cat /sys/devices/system/clocksource/clocksource0/available_clocksource
acpi_pm jiffies hpet tsc pit
$ cat /sys/devices/system/clocksource/clocksource0/current_clocksource
tsc
Providing "clocksource=tsc" to any available kernel for FC6 x86_64
didn´t solve the drift
and /sys/devices/system/clocksource/clocksource0/available_clocksource
still only contains jiffies.
So I am stuck either with a drift in the system clock or with an 32bit
system. Since the system has 8 GB of memory installed (and my system
loves that and shares that love with good performance for me) I would
like to go with an 64bit kernel.
any Ideas?
thx
Henry
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