svn commit: r219700 - head/sys/x86/x86
imp at bsdimp.com
Thu Mar 24 23:26:15 UTC 2011
On 03/23/2011 06:34, John Baldwin wrote:
> On Thursday, March 17, 2011 5:06:09 pm Jung-uk Kim wrote:
>> On Thursday 17 March 2011 04:01 pm, Peter Jeremy wrote:
>>> On 2011-Mar-16 16:44:08 +0000, Jung-uk Kim<jkim at FreeBSD.org> wrote:
>>>> Revert r219676.
>>> Thanks also. For extra kudos, how about adding a similar function
>>> to allow the HPET frequency to be over-ridden. That is currently
>>> the only timecounter that does not allow the user to compensate for
>>> incorrect hardware frequencies.
>> 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.
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