On Mon, Jan 09, 2017 at 08:53:27AM -0500, J William Piggott wrote:
>
>
[...]
>
> It is true, I suggested picking up the orphaned adjtimex(8) code as an
> alternative to inserting it's functionality into hwclock(8). However, I
> have since learned that the useful functions of adjtimex(8) are
> available via the ntp utilities. The rest of its (dis)abilities have
> the same problems we are seeing when reimplementing them into
> hwclock(8). I think perhaps there were good reasons adjtimex(8) was
> abandoned. Before, I believed adjtimex(8) might be a good fit for
> util-linux, now I am not so sure. If someone demonstrates a useful
> purpose for it I will change my position.
>
>
I use "adjtimex" from the package in "Debian" to regulate the system
clock. "Debian" has made some changes and I too, that I have not yet sent
to them.
I do not use NTP (ntpdate-debian) except when the system clock deviates
more than 3 seconds from the right time. Then I update the system clock and
correct the hardware clock accordingly and let "hwclock" calculate a new
value for the drift (hwclock --systohc --update-drift).
I have added a option '-A' to my version of "adjtimex", to compare the
system and hardware clock about every 11 minutes (after a period of
different long pauses of comparisons) and change frequency and tick to keep
the system clock in compliance with the drift-corrected hardware clock.
My computer is only on for a few hours a day. The hardware clock is never
automatically updated on shutdown nor in the process of booting.
N.B. The WARNING is caused by not updating the hardware clock but relying on
the calculated drift to correct it. The offset of the system clock is now
-0.692 seconds. The hardware clock was last updated 1st June 2016.
The time between comparisons is 30 seconds multiplied by the first
Fibonacci numbers, excluding a repeated number.
Example of comparisons:
######## Start
1483984488 Mon Jan 9 17:54:48 UTC 2017
WARNING: CMOS time is 6.25 min behind system clock
--- current --- -- suggested --
cmos time system-cmos error_ppm tick freq tick freq
1483984488 0.005348 9999 4012975
1483984518 0.005172 -5.9 9999 4012975 9999 4397870
WARNING: CMOS time is 6.25 min behind system clock
--- current --- -- suggested --
cmos time system-cmos error_ppm tick freq tick freq
1483984519 0.002689 9999 4397870
1483984579 0.001900 -13.1 9999 4397870 9999 5259588
WARNING: CMOS time is 6.25 min behind system clock
--- current --- -- suggested --
cmos time system-cmos error_ppm tick freq tick freq
1483984580 0.004296 9999 5259588
1483984670 0.002953 -14.9 9999 5259588 9999 6237539
WARNING: CMOS time is 6.25 min behind system clock
--- current --- -- suggested --
cmos time system-cmos error_ppm tick freq tick freq
1483984671 0.009972 9999 6237539
1483984821 0.007474 -16.7 9999 6237539 10000 775398
WARNING: CMOS time is 6.25 min behind system clock
--- current --- -- suggested --
cmos time system-cmos error_ppm tick freq tick freq
1483984822 -0.005831 10000 775398
1483985062 0.005554 47.4 10000 775398 9999 4220208
WARNING: CMOS time is 6.25 min behind system clock
--- current --- -- suggested --
cmos time system-cmos error_ppm tick freq tick freq
1483985063 0.007414 9999 4220208
1483985453 0.000203 -18.5 9999 4220208 9999 5432026
WARNING: CMOS time is 6.25 min behind system clock
--- current --- -- suggested --
cmos time system-cmos error_ppm tick freq tick freq
1483985454 0.001917 9999 5432026
1483986084 0.005602 5.8 9999 5432026 9999 5048743
WARNING: CMOS time is 6.25 min behind system clock
--- current --- -- suggested --
cmos time system-cmos error_ppm tick freq tick freq
1483986085 0.016335 9999 5048743
1483986715 0.004416 -18.9 9999 5048743 9999 6288698
1483987345 0.023767 30.7 9999 6288698 9999 4275678
1483987975 0.027384 5.7 9999 4275678 9999 3899389
1483988605 0.015368 -19.1 9999 3899389 9999 5149314
1483989235 0.019079 5.9 9999 5149314 9999 4763352
1483989865 0.022661 5.7 9999 4763352 9999 4390684
1483990495 0.026288 5.8 9999 4390684 9999 4013452
1483991125 0.014275 -19.1 9999 4013452 9999 5263079
1483991755 0.033575 30.6 9999 5263079 9999 3255391
1483992385 0.021591 -19.0 9999 3255391 9999 4501993
1483993015 0.025241 5.8 9999 4501993 9999 4122356
The offset of the system clock is now -0.677 seconds.
--
Bjarni I. Gislason
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