[ntp:questions] Red Hat vote for chrony

Charles Swiger cswiger at mac.com
Mon Dec 8 16:35:45 UTC 2014

On Dec 7, 2014, at 7:27 PM, William Unruh <unruh at invalid.ca> wrote:
> On 2014-12-07, Charles Swiger <cswiger at mac.com> wrote:
>> On Dec 6, 2014, at 8:33 AM, William Unruh <unruh at invalid.ca> wrote:
>>> On 2014-12-06, Charles Swiger <cswiger at mac.com> wrote:
[ ... ]
>> Dude, give it a rest.  You've just acknowledged that the chrony docs at the URL
>> ending with "manual.html" directly above recommend using maxpoll=4 to the LAN.
> No, the FAQ has that as an example. 
>> Yes, the default values compiled into chrony of minpoll=5 maxpoll=10 are nearly
>> the same as what ntpd uses, which is polite when talking to the NTP pool or
>> other WAN sources that you haven't made prior arrangements with.
>> Can we skip the pendantry involved between "default" and "recommended",
>> especially when you seem to prefer the recommended faster polling yourself?
> Especially when the document you quote does not use the word
> "recommended" It uses the word "example".

Um, the first sentence of section 5.3.4 uses the word 'recommended'.
I was going to quote it yet again for the third time, but I saw
that Miroslav just replied saying that he wrote that section.

You can argue this point further with him if you chose.

[ ... ]
>> When ntpd has been up for a while using default maxpoll=10, how many past polls
>> are available (per timesource), and what interval of time does that represent?
>> You answered that below, in fact:
>> "Note that before it actually runs, it does remember the past 8 offsets AND delays,"
>> ...which turns into 8 * 1024 seconds ~= 2.27 hours.  If we cannot manage to
>> agree that this data is kept in memory by ntpd, then further discussion of what
>> ntpd might or might not do in "discarding 7 out of 8 polls" and so forth is
>> completely moot.
> It is not used to set the clock. NOte that I will agree that ntpd also
> writes to a file the measurements in the logs. So what? It is not used
> by ntpd.

You've acknowledged that it keeps the data around, which means it remembers
that information.  The source code to clock_combine() was just posted by
David Woolley.

>> (Starting from a false premise proves nothing about the following conclusion.)
>>> Since you keep wanting to say I am wrong, why do you not tell us how
>>> ntpd works in your understanding?
>> Let me provide three responses:
>> 1) I'd prefer you to say things which are accurate as to fact rather than arguing.
>> 2) If you believe a statement I've made to be mistaken, feel free to point it out.
>> 3) I'd rather test and submit patches than try to educate someone who doesn't want to learn.
> Thought so. I interpret 1 as "I don't know",

You'd be wrong in that intepretation if that's what you think I meant.

> 2 as "the fewer statements I make the less others can point out".

I don't think I've avoided making statements in this thread.

Either point out specific issues, if any, or you can make
general handwaving notions instead and pretend that you've
identified a specific issue without ever identifying one.

> For 3) how many patches and to what have you submitted?

You can google my name and tvtohz, setitimer, or "wakeup latency" and get
results like:


The discussion was specifically including FreeBSD, DragonFlyBSD, Darwin/MacOS,
but should be relevant to the other BSD variants like NetBSD and OpenBSD.


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