| Re: [chrony-dev] [PATCH] MacOS X - add drift removal |
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- To: chrony-dev@xxxxxxxxxxxxxxxxxxxx
- Subject: Re: [chrony-dev] [PATCH] MacOS X - add drift removal
- From: Bryan Christianson <bryan@xxxxxxxxxxxxx>
- Date: Wed, 12 Aug 2015 08:00:06 +1200
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> On 11/08/2015, at 10:59 pm, Miroslav Lichvar <mlichvar@xxxxxxxxxx> wrote:
>
> On Thu, Aug 06, 2015 at 04:57:43AM +1200, Bryan Christianson wrote:
>>> @@ -119,7 +119,7 @@ start_adjust(void)
>>> }
>>>
>>> UTI_DiffTimevalsToDouble(&elapsed, &T1, &T0);
>>> - accrued_error = elapsed * current_freq;
>>> + accrued_error = (elapsed + DRIFT_REMOVAL_INTERVAL / 2.0) * current_freq;
>>>
>>> adjust_required = - (accrued_error + offset_register);
>>
>> This changes the effective drift (as seen in tracking.log) from 18ppm to 6ppm but System time still hovers around -10us
>
> If it changes the reported drift, it doesn't work as intended :). The
> problem probably is that the the precorrection is not included in the
> offset register and when the adjustment is stopped, the register will
> be off by that value.
>
> How about this?
This works really well :) I'm now seeing System time vary += 5 usecs with LAN connected servers. Please commit the change (or I can submit a patch if you prefer)
--
Bryan Christianson
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