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Description of problem: ntpd does not work my system : MB Gigabyte + Core i7 920 + 6 GB ram uname -r 2.6.38.8-32.fc15.i686.PAE Version-Release number of selected component (if applicable): ntp-4.2.6p3-4.fc15.i686 How reproducible: When I start the machine, I have: systemctl status ntpd.service ntpd.service - Network Time Service Loaded: loaded (/lib/systemd/system/ntpd.service) Active: active (running) since Thu, 23 Jun 2011 18:11:25 +0200; 5h 32min ago Main PID: 911 (ntpd) CGroup: name=systemd:/system/ntpd.service └ 911 /usr/sbin/ntpd -n -u ntp:ntp -g 5 hours later, the time is wrong, so I do: systemctl stop ntpd.service systemctl start ntpdate.service to set the good time. and a "grep ntpd /var/log/messages" shows: ntpdate[31156]: step time server 145.238.203.10 offset 809.777667 sec i.e in 5 hours the system is 12 mn late !!
Such large drift is usually a hw or kernel problem. ntp can adjust the clock rate at most by ~2 seconds per hour, in your case it would need to make 80 times larger adjustment! You may have better luck with chrony, it can adjust the clock rate up to 10%, but it's really the underlying hw/kernel issue that needs to be fixed here.
Thx I'll try it and report the result.
What clocksource is it using? I have: # grep "" /sys/devices/system/clocksource/clocksource0/* /sys/devices/system/clocksource/clocksource0/available_clocksource:tsc hpet acpi_pm /sys/devices/system/clocksource/clocksource0/current_clocksource:tsc Also please attach the output of the "dmesg" command (as a plaintext attachment.)
Created attachment 509902 [details] result of "dmesg" Here is the file dmesg requested.
(In reply to comment #3) > What clocksource is it using? > > I have: > # grep "" /sys/devices/system/clocksource/clocksource0/* > /sys/devices/system/clocksource/clocksource0/available_clocksource:tsc hpet > acpi_pm > /sys/devices/system/clocksource/clocksource0/current_clocksource:tsc > > Also please attach the output of the "dmesg" command (as a plaintext > attachment.) I have the same: root # grep "" /sys/devices/system/clocksource/clocksource0/* /sys/devices/system/clocksource/clocksource0/available_clocksource:tsc hpet acpi_pm /sys/devices/system/clocksource/clocksource0/current_clocksource:tsc And finally, I have already submitted this bug on Fedora 12, with the same hw.
And does booting with "clocksource=hpet" fix the timekeeping?
Is this a command that I must enter on the kernel line of grub.conf ? For the test, I'll try, but for this test I must wait a while, because I switched to chrony as said in comment #1
Yes, it's the kernel line in grub.conf. You can also switch it temporarily (until next boot) by echo hpet > /sys/devices/system/clocksource/clocksource0/current_clocksource What's the output of "chronyc tracking"? When the frequency value is below 500 ppm and the skew is small enough (say below 50 ppm), ntpd should work too.
Hi here is the output : /root # chronyc tracking Reference ID : 145.238.203.10 (syrte8.obspm.fr) Stratum : 3 Ref time (UTC) : Tue Jun 28 09:06:48 2011 System time : 0.000000 seconds fast of NTP time Frequency : 32768.000 ppm slow Residual freq : 4.718 ppm Skew : 261.840 ppm Root delay : 0.021332 seconds Root dispersion : 0.038422 seconds So, ntp worked sometimes and sometimes not, its was as a lottery and I'm glad to have chrony working fine! But however I shall try soon the command you gave me with ntpd
"(In reply to comment #6) > And does booting with "clocksource=hpet" fix the timekeeping? Finally I can confirm that this option in the kernel line resolves the issue. Thx a lot !