Re: [chrony-users] gpsd, pps and chrony

[Bill Unruh <unruh@xxxxxxxxxxxxxx>]

I am afraid I have never gone into the Linux entrails to figure out how the HZ
variable works and how it interacts with chrony.


On Tue, 5 Apr 2011, Ed W wrote:

> > That is not a config error. It is a "hardware" error-- the clock is
> > irredemably broken. (Fortunately it was just your kernel config that
> > broke it
> > so you could recover, but chrony could not)
>
>
> OK, so I have chrony built in a uclibc chroot with /usr/src/linux holding a
> 32bit kernel with HZ set to 1024 (I think).  The host is a 64bit kernel with
> HZ set to 250 - however, I don't think this should be relevant?
>
> This is then installed on my Alix (32bit only). If I set "linux_hz 1024" in
> my conf file I get:
>
> Apr  5 22:05:38 localhost user.info chronyd[3457]: chronyd version DEVELOPMENT starting
> Apr  5 22:05:38 localhost user.info chronyd[3457]: Set system time, error in RTC = -9.552346
> Apr  5 22:05:37 localhost user.info chronyd[3457]: set_config_hz=1 hz=1024 shift_hz=7 basic_freq_scale=0.12500000 nominal_tick=977 slew_delta_tick=81 max_tick_bias=97
> Apr  5 22:05:37 localhost user.info chronyd[3457]: Linux kernel major=2 minor=6 patch=37
> Apr  5 22:05:37 localhost user.info chronyd[3457]: Frequency -136.274 +- 0.078 ppm read from /var/lib/chrony/drift
> Apr  5 22:05:37 localhost user.crit chronyd[3457]: Fatal error : adjtimex failed for set_frequency, freq_ppm=1.3627e+02 scaled_freq=1.3627e+02 required_tick=977
>
>
>
> If I leave off all linux_hz config I get:
>
> Apr  5 22:06:10 localhost user.info chronyd[3479]: chronyd version DEVELOPMENT starting
> Apr  5 22:06:10 localhost user.info chronyd[3479]: Set system time, error in RTC = -9.553227
> Apr  5 22:06:11 localhost user.info chronyd[3479]: set_config_hz=0 hz=100 shift_hz=7 basic_freq_scale=1.28000000 nominal_tick=10000 slew_delta_tick=833 max_tick_bias=1000
> Apr  5 22:06:11 localhost user.info chronyd[3479]: Linux kernel major=2 minor=6 patch=37
> Apr  5 22:06:11 localhost user.info chronyd[3479]: Frequency -136.274 +- 0.078 ppm read from /var/lib/chrony/drift
> Apr  5 22:06:11 localhost user.alert kernel: [ 1704.211743] grsec: time set by /usr/sbin/chronyd[chronyd:3479] uid/euid:0/0 gid/egid:0/0, parent /bin/busybox[init:1] uid/euid:0/0 gid/egid:0/0
> Apr  5 22:06:19 localhost user.info chronyd[3479]: System trim from RTC = -0.593289
> Apr  5 22:06:20 localhost user.info chronyd[3479]: System's initial offset : 0.001843 seconds slow of true (slew)
> ...
>
>
> My question is why I see "hz=100" and why the 1024 config causes the fatal error?
>
> I'm fairly sure I was still getting hz=100 in the logs when built against a kernel source using 1000hz and 250hz. Also I only looked at the config code quickly, but I can't see where it's trying to read the kernel HZ value at compile time?
>
> What am I missing?
>
> Note, seems to be working fine without any config stanzas, I just thought it curious?
>
> Ed W
>
> ---
> To unsubscribe email chrony-users-request@xxxxxxxxxxxxxxxxxxxx
> with "unsubscribe" in the subject.
> For help email chrony-users-request@xxxxxxxxxxxxxxxxxxxx
> with "help" in the subject.
> Trouble?  Email listmaster@xxxxxxxxxxxxxxxxxxxx.

--
William G. Unruh   |  Canadian Institute for|     Tel: +1(604)822-3273
Physics&Astronomy  |     Advanced Research  |     Fax: +1(604)822-5324
UBC, Vancouver,BC  |   Program in Cosmology |     unruh@xxxxxxxxxxxxxx
Canada V6T 1Z1     |      and Gravity       |  www.theory.physics.ubc.ca/

---
To unsubscribe email chrony-users-request@xxxxxxxxxxxxxxxxxxxx 
with "unsubscribe" in the subject.
For help email chrony-users-request@xxxxxxxxxxxxxxxxxxxx 
with "help" in the subject.
Trouble?  Email listmaster@xxxxxxxxxxxxxxxxxxxx.