David J Taylor wrote: > "Alan" <greig...@netscape.net> wrote in message > news:z9i5n.58805$q36.5...@newsfe19.ams2... >> Would like to get to the bottom of this as well. Using 4.4.6-o with -M , >> I get "Frequency error 3030 PPM exceeds tolerance 500 PPM". Considering >> that without =M the frequency modification is only about 5 PPM then >> obvioulsy something very strange is going on. It seems that even if the >> timer precision is increased by another program then time immediately >> starts to drift rapidly by hundreds of milliseconds.
Yes, looks like timing is seriously broken on your hardware. Dave Hart, isn't there a way to force disabling time interpolation with your binaries even if the system time increments in 15.625 ms steps? Maybe this could be wort a try in this special case. > Alan, > > Our experience was that the switching between normal and high-resolution > timers caused steps of many milliseconds (I don't recall the exact figure) > which really messed up NTP. So either run with no MM timers at all, or > run with the MM timers permanently enabled, and NTP recognises that > change, and adjusts accordingly. Have NTP start the MM timers was one > solution, and hence the -M option. > > It might be helpful to know what the event log says with both sets of > startup parameters, as there may be a clue there which Dave Hart, the > person closest to this code, can interpret. > > I must confess to having nagging doubts about AMD (but with no good > reason), AFAIK the CPU type (Intel or AMD, CPU family ...) should not matter if the PM timer is used for QPC instead of the TSCs. However, as I've mentioned in a different reply, the problem may be due to a fault chipset. The Linux kernel identifies quite a number of problematic hardware and displays appropriate warnings at startup, so booting a current Linux system (maybe from a Live CD) on that machine and watching the startup messages *may* give some hints. > about whether you have another program setting the time (check > that w32time.exe is not running - Show Processes from all users), and > perhaps something in the BIOS. One final idea (which there was no option > on my test system) might be to start with just one CPU active in the BIOS. I doubt the problem may be due to a different time sync program running since the problem occurs if and only if the MM timer tick rate is changed. Martin -- Martin Burnicki Meinberg Funkuhren Bad Pyrmont Germany _______________________________________________ questions mailing list questions@lists.ntp.org http://lists.ntp.org/listinfo/questions