Fedora 8's kernels drift excessively; from as little as 24 seconds/day to upwards of an hour. Fedora Core 6's base install kernel (2.6.18-1.2798.fc6.i686) works fine, as does Suse 10.1 (2.6.16.13-4). Changing the clocksource to pit, hpet, jiffies or acpi_pm doesn't help, and some even make it worse. Using "nohz=off highres=off " does not solve the problem (as per Fedora wiki instructions). The behavior manifests itself on HP's dc7700 and their rp5700. HP has confirmed the following: The RTC is within expected tolerance The 8254 is within expected tolerance The HPET is within expected tolerance The Vista system time is within expected tolerance The WXP system time is within expected tolerance The Suse 10.1 Linux system time is within expected tolerance The Fedora Core 8 (various kernels) show out of tolerance system time on a multitude of platforms and a multitude of kernel builds. We can provide demsg, lspci, or any other information needed.
Try booting with clocksource=acpi_pm if that's not what was selected by the kernel (cat /sys/devices/system/clocksource/clocksource0/current_clocksource). This should solve the problem.
Oops, didn't see that changing the clocksource didn't help. It's expected that some would have made it worse on an SMP system. Just for the record, what is the current clocksource?
The current clocksource on the dc7700 and rp5700 is "tsc."
Possibly fixed by this commit, but it seems to imply the maximum drift observed was 283ppm: Gitweb: http://git.kernel.org/git/?p=linux/kernel/git/torvalds/linux-2.6.git;a=commit;h=e13a2e61dd5152f5499d2003470acf9c838eab84 Commit: e13a2e61dd5152f5499d2003470acf9c838eab84 Parent: 25f666300625d894ebe04bac2b4b3aadb907c861 Author: john stultz <johnstul.com> AuthorDate: Sun Feb 10 10:48:03 2008 +0100 Committer: Thomas Gleixner <tglx> CommitDate: Sun Feb 10 10:48:03 2008 +0100 ntp: correct inconsistent interval/tick_length usage
Patch believes that the ntp.c patch has already been applied to kernel-2.6.23.15-137.fc8. I applied the timex.h patch and rebuilt, but it had no effect on the clock drift.
We have been able to reduce the drift to ~1.5 secs every 24 hrs on a single- CPU unit by adjusting the kernel's tick & frequency settings: /sbin/adjtimex --tick 10002 --frequency -1048576 On a dual core unit, the drift is ~3 secs very 24 hrs w/ those settings.
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Fedora 8 changed to end-of-life (EOL) status on 2009-01-07. Fedora 8 is no longer maintained, which means that it will not receive any further security or bug fix updates. As a result we are closing this bug. If you can reproduce this bug against a currently maintained version of Fedora please feel free to reopen this bug against that version. Thank you for reporting this bug and we are sorry it could not be fixed.