On Tue, Feb 19, 2008 at 07:37:32AM -0600, Moshe Yudkowsky wrote: > I had a very kind private communication from a list member. Let me > reformulate my question. > > On the AMD64 dual-core platform, the system clock has far too much drift > even though the hardware clock seems well behaved. I don't seem to be > experiencing the "double-speed clock" problem that I see references to > on the net as of a few years ago, but I am experiencing some other odd > behavior. The most likely culprit, as far as I can tell from research, > is some interaction between the hardware's ability to adjust CPU clock > speed to save power/control temperature (which then influences the > system clock's theory of what a CPU tick means in terms of actual time > passing) with the dual-core mode. > > But that seems rather wacky. I find it hard to believe that a kernel > release wouldn't work on dual core CPUs. > > But if the problem really is that's the case, I would like to know what > boot-time settings I can use to test this hypothesis. For that matter > I'd like to know why the kernel itself isn't picking up on this > theoretical problem -- ISTR reading about an "enhanced" CPU clock mode > that could solve this problem, but I can't find references to it or how > to build a kernel or modules from source that would include this capability. > > I've spent a substantial amount of time on this problem, and I can't > come to any conclusion. I have to wonder if it's a problem with NTP > itself, but if so it's a problem that only manifests itself on the AMD64 > box, although I continue to fiddle with NTP settings.
Someone here at work was having trouble getting NTP working on their system a few weeks ago. Disabling spread spectrum in the BIOS solved the problem. Of course as far as I know disabling spread spectrum violate emmisions certifications in europe, but I could be wrong about that since I don't actually live there (anymore at least). Spread spectrum clocking really screws with the timings NTP depends on. -- Len Sorensen -- To UNSUBSCRIBE, email to [EMAIL PROTECTED] with a subject of "unsubscribe". Trouble? Contact [EMAIL PROTECTED]