[ntp:questions] Red Hat vote for chrony

Paul tik-tok at bodosom.net
Sat Dec 6 20:35:10 UTC 2014


On Sat, Dec 6, 2014 at 11:12 AM, William Unruh <unruh at invalid.ca> wrote:

> And in my tests 10 years ago or so, I used a local gps clock to test the
> ability of chrony and ntpd to discipline a computer clock networked to
> another server which was disciplined by a gps. Thus the network was the
> same, and the difference was ntpd vs chrony.
> chrony was better. Primarily, I think, because chrony responded more
> quickly to drift rate changes due to temp changes.
>

I looked at your data back in the day.  Even then I thought they were old.
Of course if the secret sauce is loop constants (I haven't read the Chrony
architecture document, maybe because there isn't one) then perhaps the
results would still be the same.


> > Other's will be convinced because they can run Chrony on a Unix laptop
> and save power or discipline a clock with only a few minutes a day of
> connect time.  I don't know who those people are.
>
> Both chrony and ntpd
> send out the same packets and both have roughly the same polls, so where
> is this "powersaving" coming from?)
>

And I thought you were chugging the kool-aid:

Using chrony over ntp has also other advantages:

   - smaller memory footprint (1.3MB vs 6MB resident size)
   - no unnecessary process wakeups, this is good for powersaving. The ntpd
   process normally wakes up every second.
   ...

For me it's consistency.  I want to run the same timekeeping software
"everywhere"* and Chrony doesn't run "everywhere".

*my everywhere is obviously not anyone else's everywhere.


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