Re: [Linuxptp-devel] Optimal P, I constants

[Richard C. <ric...@gm...>]

On Fri, May 10, 2013 at 05:12:31PM +0200, Miroslav Lichvar wrote:
> On Fri, May 10, 2013 at 10:41:13AM +0200, Richard Cochran wrote:
> > I spent some time this week reviewing how to obtain good PI servo
> > constants, and now I am even more convinced that the choice involves
> > tradeoffs that only the end user can decide.
> 
> What tradeoffs do you think the user can consider? For me, the only
> things that matter are time error, frequency error and convergence
> time.

Yes, that pretty much says it all.

> > 2. Should user constants appear in the config file, or should we have
> >    a new, separate file for that?
> 
> How about a list of EXP:P:I triplets separated by commas in the config?

I was thinking something more like:

#		Sync	P	I
pi_constant	0	0.7	0.3
pi_constant	-1	0.58	0.085

In that way, a config file can personalize as much or as little of the
table as desired.

Thanks,
Richard