Re: [Linuxptp-users] About ptp4l sync completed time

[Takahiro S. <tsh...@gm...>]

Hello Keller,

Thank you for the suggestion.

I doubted the wrong part.
Now the sync completion time is fine by the latest ptp4l.

Thanks and Best regards,
Takahiro Shimizu
2012/3/10 Keller, Jacob E <jac...@in...>

>  ** **
>
> ** **
>
> *From:* Takahiro Shimizu [mailto:tsh...@gm...]
> *Sent:* Friday, March 09, 2012 1:34 AM
> *To:* Richard Cochran; lin...@li...
> *Subject:* Re: [Linuxptp-users] About ptp4l sync completed time****
>
> ** **
>
> Hello Richard,
>
> Thank you for the reply.****
>
> ** **
>
> No, it is not normal.
>
> With hardware time stamping, you should get withn 0.1 usec in about
> one or two minutes.****
>
>  ** **
>
> OK. I see. I will check the driver again.****
>
> ** **
>
> Here is the result of ptp4l.****
>
> After 5 sec, master offset is decreasing gradually.****
>
> I doubt the part of adjust in the ptp driver now.****
>
> ** **
>
> time (sec)       master offset (ns)        adj       path delay (ns)****
>
> 1        60830880        0          5664****
>
> :****
>
> : <snip>****
>
> :****
>
> 4420  -20       32758513        2964****
>
> 4421  -54       32758473        2966****
>
>   ****
>
> > 2. Can I speed up the time till sync completed?
>
> The clock servo (in pi.c) has a PI controller, and its constants do
> affect the convergence performance.
>
> However, I think you have errors in the time stamps, or missing time
> stamps.
>
> HTH,
> Richard****
>
>  I see. I will check it too.****
>
> ** **
>
> Thanks and Best regards,****
>
> Takahiro Shimizu****
>
> ** **
>
> I would suggest looking into your clock rate adjustment function. This is
> where the driver should be tuning the frequency of the clock. It might be
> possible that you aren’t adjusting it correctly.****
>
> ** **
>
> However, I should note that with my testing, different values in the PI
> servo can have a fair impact on convergence times. You might play around
> with those and see what kind of impact it has. I don’t think changing those
> alone will be enough but it might help you find the cause of the issue.***
> *
>