svn commit: r219700 - head/sys/x86/x86
brde at optusnet.com.au
Fri Mar 25 10:02:18 UTC 2011
On Thu, 24 Mar 2011, Warner Losh wrote:
> On 03/23/2011 06:34, John Baldwin wrote:
>> On Thursday, March 17, 2011 5:06:09 pm Jung-uk Kim wrote:
>>> I really hate the idea of adjusting timecounter frequency from
>>> userland. I guess "use ntpd(8)" is not a good answer for some
>>> people. :-(
>> Actually, that doesn't work well if your timecounter frequency is off by a
>> lot. Having the timecounter frequency accurate improves the accuracy of
>> things like ntpd and ptpd.
> ntpd requires that the time counter be within 128ppm of true. If the time
> counter guess is off by more than that, you lose: ntpd won't work.
Is ntpd really that broken? What does it do if the drift file has the
correct compensation to within 128 ppm?
I use an old version of ntpd in which I've observed a positive feedback
loop when -x is used to prevent steps and the slew wants to be more than
128 ppm due to a transient.
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