SMP and NTPD

[Eric Mader]

I also noticed the following in /var/log/messages:

Apr 11 09:21:19 localhost kernel: warning: many lost ticks.
Apr 11 09:21:19 localhost kernel: Your time source seems to be instable 
or some driver is hogging interupts


I'll bet this has something to do w/ the problem. (:-) Does anybody know 
how to figure out what this is about?

(I have a vague memory of having seen the same problem w/ the SMP kernel 
on a P4 w/ hyperthreading. On this system it was so bad that the whole 
system would lock up. My AMD keeps chugging along, more or less.)

Regards,
Eric

Eric Mader wrote:
> Hello,
> 
> I'm running kernel 2.6.11-1.1369_FC4smp on an AMD64 x2 system. A couple 
> of days ago I noticed that NTPD wasn't keep time very well. I did some 
> investigating and found out that the jitter from the time servers kept 
> going up and up - after an hour the jitter will be several seconds.
> 
> As an experiment, I tried running the non-smp kernel, and NTPD was able 
> to keep rock-solid sync. After more than an hour, the jitter was only a 
> few milliseconds.
> 
> I'm guessing that this points to some problem w/ the SMP kernel. Can 
> anybody confirm this, or suggest what else the problem might be?
> 
> My system:
> ASUS A8V Delux
> AMD Athlon 64 X2 4200+
> 1 GM memory (512 MB x 2)
> WD1200JJ (w/ Windows XP x64)
> WD400BB (w/ FC4)
> NEC DVD RW 3520A
> TDK CDRW 5200B
> NVidia GeForce 6600 (ASUS brand)
> Samsung SyncMaster 204T (connected through a DVI KVM)
> USB Keyboard and mouse (connected through KVM)
> 
> Regards,
> Eric Mader
>