Re: [nm-wg] standard timestamp format

[Adrian Cockcroft <Adrian.Cockcroft@Sun.COM>]

timestamp intervals are differenced to provide a duration, and A-B 
needs to be in common units for A and B

Adrian

On Jun 17, 2004, at 1:30 PM, Dan Gunter wrote:

> > > I would suggest that the units be an optional parameter, since they 
> > > aren't always needed, and maybe aren't always known, i.e. in the 
> > > case of some kind of hardware clock.
> > If you don't know the clock frequency then the data is meaningless,
> > the units should be nanoseconds and you should multiply whatever the
> > source clock rate is by some implementation and source specific 
> > factor to get to nanoseconds. For the simplest portable java code 
> > that would
> > be 1000000 to go from milliseconds. Linux doesn't require a hires 
> > counter but I think some implementations may have one, Solaris always
> > has gethrtime regardless of whether its on SPARC or x86, I know 
> > HP-UX, AIX and windows have hires counters.
> Not meaningless; if I'm comparing intervals A and B, I don't need any 
> units to say that A/B = 1.5. But I see your point that in general we 
> want to know what the time intervals really represent. So, sure, let's 
> make nanoseconds the standard units. One less piece of metadata to 
> worry about. In cases where the units aren't needed, it might as well 
> be nanoseconds [ignoring issues with misinterpretation, since this is 
> such an edge case anyways].
>
> -Dan
>
> > Adrian