SMP and NTPD

Jeff Vian jvian10 at charter.net
Thu Apr 13 13:06:57 UTC 2006


On Wed, 2006-04-12 at 14:40 -1000, Eric Mader wrote:
> 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.)
> 
The kernel 2.6.11-1.1369_FC4smp is ancient! I believe that was the
kernel FC4 was released with.

Have you tried updating the system to the latest software to see if the
problem you describe may have been fixed at some point in the last 7
months?


> 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
> > 
> 




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