Re: [chrony-dev] [GIT] chrony/chrony.git branch, master, updated. 1.26-26-g9a01ccc

[Miroslav Lichvar <mlichvar@xxxxxxxxxx>]

On Fri, Nov 25, 2011 at 10:39:33AM +0000, Ed W wrote:
> On 25/11/2011 10:12, Ed W wrote:
> > As you have clearly started to push the boundaries of curve fitting
> > here, have you considered switching to some kind of Kalman filtering
> > technique?  Implemented correctly this can potentially simultaneously
> > incorporate the updating of the estimate and tracking the estimated
> > error.  I haven't thought about it enough, but it might also make it
> > simpler to incorporate exotic ideas such as more active changes in
> > measurement intervals in response to changing estimated error..? 
> 
> Hmm, some googling shows that this is a fairly well discussed idea in
> academic circles.  I found this article enlightening
> 
> http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.163.7440

Interesting. It seems this could be used to improve our temperature
compensation code to determine the coefficients automatically, but
does it apply to the more common case without temperature data?

I know two places in the chrony code which might benefit from some new
ideas. The sample weight calculation and the pruning of old samples.

Currently, on top of my todo list is NTP4 support and clock combining.
If you have any patches to improve the performance I'll be happy to
test it in the simulator (or help you set it up).

-- 
Miroslav Lichvar

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