[ntp:questions] Re: Windows timekeeping - sudden degradation - why?
martin.burnicki at meinberg.de
Thu Dec 8 08:17:44 UTC 2005
David J Taylor wrote:
> David J Taylor wrote:
>> Martin Burnicki wrote:
>>> If the MM timer is set constantly to high resolution then you should
>>> observe a little more jitter than with default resolution, but the
>>> large steps should go away. So as a test you just might to start
>>> Quicktime and watch if the offset settles down.
> Well, with the MM timer permanently running (from 17:00 Wednesday) I can
> report that things are /much/ better, see:
> - the offset first shot up to 120ms, but is now gently decaying towards
> - the jitter figures seem much better, around 1 (LAN servers) - 2ms (WAN
> - the drift value has changed from -65 down to -9.3ms.
Those results are exactly what I've expected.
> I would certainly like the option, for this system at least, of running
> with the MM timers permanently in its high resolution mode.
Agreed. Maybe Danny and Harlan accept my patch.
> I would also be interested in determining which program is switching the
> MM timer speed, and thereby upsetting the otherwise excellent timekeeping
> on this system. I wonder if there's a relatively easy way to determine
Unfortunately there's no way to find that out, AFAIK. You can only observe
the effects indirectly.
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