Re: [gpsd-dev] Print offset in ntpshmmon?

[Miroslav Lichvar]

On Thu, Apr 30, 2015 at 11:08:31AM -0700, Gary E. Miller wrote:
> On Thu, 30 Apr 2015 17:27:40 +0200
> Miroslav Lichvar <address@hidden> wrote:
> > On Tue, Apr 28, 2015 at 11:59:06AM -0700, Gary E. Miller wrote:
> > > > > > > -                    offset = (float(record[3]) -
> > > > > > > float(record[4]))
> > > > > > > +                    offset = float(record[4])
> > > > > > 
> > > > > > Both are pretty bad....

> > But would be pystripchart able to display the data without losing
> > precision?
> 
> Sure, the offset is the residue of the preccision.

I meant the precision that would be gained for large offsets by not
parsing the value as a float. If pystripchart uses floats internally,
it won't matter if the offset is printed by ntpshmmon and parsed by
ntpshmviz as a pair of integers.

> > Offset is normally close to zero. I think printing the offset in
> > ntpshmmon as a double and parsing it as a float in ntpshmviz would be
> > fine.
> 
> Nope.  The calcuation is being done in double and the nanoSec are lost.

The change I proposed only prints the offset as a double, the
substraction of the two timestamps is done with integers.

-- 
Miroslav Lichvar