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

[Keller, J. E <jac...@in...>]

> -----Original Message-----
> From: Richard Cochran [mailto:ric...@gm...]
> Sent: Friday, May 10, 2013 10:21 AM
> To: Miroslav Lichvar
> Cc: lin...@li...
> Subject: Re: [Linuxptp-devel] Optimal P, I constants
> 
> 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
> 

I agree with that, and we can just comment out the ones we don't select,
But if the user wants it is easy to just add the values they want.

- Jake