Responding to very old mail, from December...
Hal Murray :
>
> > Here's the inside view from looking at the code: --disable-kernel-PLL turns
> > off the use of ntp_adjtime() to slew time, leaving adjustments to be done at
> > much coarser granularity by the old-style
Yo Hal!
On Thu, 01 Dec 2016 23:29:23 -0800
Hal Murray wrote:
> >> There is a tangle in this area that I don't understand. When ntpd
> >> exits (or crashes), it leaves the previous state in the kernel so
> >> anybody running ntptime will think things are fine.
>
> > What previous state?
>
> Here's the inside view from looking at the code: --disable-kernel-PLL turns
> off the use of ntp_adjtime() to slew time, leaving adjustments to be done at
> much coarser granularity by the old-style adjtime(2) call.
How about we rename it to --disable-ntp_adjtime?
I assume w
us, estimated error 1600 us,
> status 0x40 (UNSYNC),
> time constant 2, precision 1.000 us, tolerance 500 ppm,
>
> The long story is that I had a setup that included --disable-kernel-PLL. (I
> don't remember why I added that.) I noticed that my daemon that records
&g
ant 2, precision 1.000 us, tolerance 500 ppm,
The long story is that I had a setup that included --disable-kernel-PLL. (I
don't remember why I added that.) I noticed that my daemon that records
things like CPU and disk temperature and NTP's drift was getting 0 for the
drift because that
Yo All!
Below are the 24 hour results for --disable-kernel-pll on a RasPi 3
with Uputronics HAT.
With --disable-kernel-pll
Local Clock Local Clock Local ClockPPS PPS
Poll Freq Offset 90% Jitter 90% Stability 90% Offset 90% Jitter 90%
1 1.36 ppm
Yo Daniel!
On Thu, 29 Sep 2016 14:34:08 -0400
Daniel Franke wrote:
> On Sep 29, 2016 2:23 PM, "Gary E. Miller" wrote:
>
> > Then maybe a worth while experimment to copy the kernel PLL into
> > ntpd to see how it works there?
>
> I can't conceive of how you'd do that. It's too tightly integr
On Sep 29, 2016 2:23 PM, "Gary E. Miller" wrote:
> Then maybe a worth while experimment to copy the kernel PLL into ntpd
> to see how it works there?
I can't conceive of how you'd do that. It's too tightly integrated with the
rest of the kernel timing subsystem and other internal kernel APIs.
__
Yo Daniel!
On Thu, 29 Sep 2016 10:06:01 -0400
Daniel Franke wrote:
> On 9/28/16, Gary E. Miller wrote:
> > The knerel PLL and the ntpd userspace PLL are supposed to be using
> > the same algorithm and constants. Might be worth checking if the
> > constants are still the same.
>
> They aren'
On 9/28/16, Gary E. Miller wrote:
> The knerel PLL and the ntpd userspace PLL are supposed to be using the
> same algorithm and constants. Might be worth checking if the constants
> are still the same.
They aren't. In ntp_loopfilter.c, we have
#define CLOCK_PLL 16. /* PLL loop gain (l
Yo All!
I just ran a 6 hour test of --disable-kernel-pll. See attached.
The left side before 18:45 is yesterday's ntpd. After that
time is today's ntpd with --disable-kernel-pll. Nothing else
changed.
As the png shows, the frequency jitter declined, but the offset
jitter increas
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