Re: Regression: can't apply frequency offsets above 1000ppm.
From: John Stultz
Date: Wed Sep 02 2015 - 19:16:08 EST
On Tue, Sep 1, 2015 at 6:14 PM, Nuno GonÃalves <nunojpg@xxxxxxxxx> wrote:
> On Wed, Sep 2, 2015 at 2:03 AM, John Stultz <john.stultz@xxxxxxxxxx> wrote:
>> On Tue, Sep 1, 2015 at 5:36 PM, Nuno GonÃalves <nunojpg@xxxxxxxxx> wrote:
>>> On Tue, Sep 1, 2015 at 9:25 PM, Thomas Gleixner <tglx@xxxxxxxxxxxxx> wrote:
>>>> On Tue, 1 Sep 2015, Nuno GonÃalves wrote:
>>>>> There is a regression on the clock system since v3.16-rc5-111-g4396e05
>>>>>  http://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/?id=4396e058c52e167729729cf64ea3dfa229637086
>>>> That commit has absolutely nothing to do with NTP. I fear your bisect
>>>> went down the wrong road somewhere.
>>> You are right. It is v3.16-rc5-114-gdc49159:
>>> I've triple checked it this time. Not sure where I did the mistake to
>>> get it wrong by 3 commits.
>> This commit is much more believable (though surprising as that change
>> was found to greatly improve results for most uses).
>> Can you provide any more details about how the problem is reproduced
>> (kernel config, what userland images are you using, etc)? I've got a
>> BBB myself so I can try to see whats going on.
> I'm using a clean Debian image:
> And just installing chrony from the feeds. With any kernel from 3.17
> you'll have wrong estimates at chronyc sourcestats.
Wrong estimates? Could you be more specific about what the failure
you're seeing is here? The
I installed the image above, which comes with a 4.1.6 kernel, and
chrony seems to have gotten my BBB into ~1ms sync w/ servers over the
internet fairly quickly (at least according to chronyc tracking).
root@beaglebone:~# chronyc tracking
Reference ID : 22.214.171.124 (time01.muskegonisd.org)
Stratum : 3
Ref time (UTC) : Wed Sep 2 23:07:05 2015
System time : 0.001320852 seconds fast of NTP time
Last offset : +0.001209910 seconds
RMS offset : 0.002978454 seconds
Frequency : 44.684 ppm fast
Residual freq : +0.068 ppm
Skew : 1.223 ppm
Root delay : 0.073661 seconds
Root dispersion : 0.021902 seconds
Update interval : 518.3 seconds
Leap status : Normal
root@beaglebone:~# chronyc sourcestats
210 Number of sources = 4
Name/IP Address NP NR Span Frequency Freq Skew Offset Std Dev
126.96.36.199 4 3 17m +1.593 30.515 +798us 802us
unlawful.id.au 6 5 21m +1.080 2.312 +2731us 273us
time.theplante.net 11 5 77m -0.536 0.915 -1165us 1044us
time01.muskegonisd.org 4 3 25m +1.677 15.256 -342us 516us
Can you send me your kernel config?
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/