Andrew On Mon, 2006-03-20 at 10:13 +0000, Andrew Schulman wrote: > Since I built my new amd64 host, my system clock is borked. It runs about > 4% fast-- gaining an hour a day. This is way to much gain for ntpd to keep > up with. To compensate I've had to set adjtimex --tick 9600, which > approximately corrects for the drift. > > This would be tolerable, except that the drift rate isn't constant. It's > all over the place. Right after I boot it's stable at about -50 PPM, but > then after a few hours it suddenly goes nuts. Look at the adjustments > ntpdate has to make when I run it once a minute: <snip> > No wonder ntpd can't keep up. The drift rate is all over the place. > > I'm running a custom 64-bit kernel 2.6.15. CPU is Athlon64 X2 4200+, > chipset is nForce4. > > Many people are reporting problems related to time with the 2.6.15 kernel on > amd64, e.g. > > http://bugzilla.kernel.org/show_bug.cgi?id=3927 > http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=354995 > http://www.ussg.iu.edu/hypermail/linux/kernel/0410.1/1505.html > > A search for "amd64 linux clock" turns them up. However, 80% or more of the > discussion seems to be about the "AMD/ATI bug", which applies to the > combination of AMD processors with some ATI chipsets (not sure which one). I > don't have an ATI chipset. Still, I've tried all of the following boot > parameters that people have recommended for this problem: > > disable_timer_pin_1 (my host won't boot) > no_timer_check > noapic acpi=off > clock=pmtmr notsc > > I also disabled CPU frequency spread spectrum in the BIOS. The result is > always the same-- the clock is stable after I boot, but a few hours later it > goes nuts again. > > Help! How can I fix my system clock? Do I a hardware problem? How can I > tell? Any help would be greatly appreciated. I can remember a story about a Sparc/Solaris system that was the time server for a network but it kept very, very bad time. It turned out it was also terminal (RS232 type) server as well. In Solaris the serial interrupt ran at a higher priority than the clock tick so it was losing a number of clock ticks every day - thus the poor time. I was wondering if something simular was happening to you? Have you got some hardware/driver that is causing the system to miss clock interrupts? Hope this helps Steve
Attachment:
signature.asc
Description: This is a digitally signed message part