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SubjectRe: time patches by Roman Zippel
Hi,

On Wed, 15 Feb 2006, Ulrich Windl wrote:

> > > Assuming 1024Hz interrupt frequency:
> > > (1µs * 1000) / 1024 == 0ns; 0 * 1024 == 0µs, not 1µs
> > > (2µs * 1000) / 1024 == 1ns; 1 * 1024 == 1.024µs, not 2µs
> >
> > Ok, I didn't put much effort into optimizing it for uncommon HZ values.
> > Why is it so important? It's currently unused on any Linux machine
> > synchronized via NTP.
>
> Roman,
>
> how do you know? When using "disable kernel", NTP relies on adjtime() to adjust
> the time. Some people even prefer that, because the algorithms do floating point
> math in user space instead of fixed-point maths in kernel space.

This still requires they choose an uncommon HZ value, which is not really
likely. Anyway, it's not really difficult to add the remainder to
time_adj_curr. Since the adjtime() has only a usec resolution and this
rounding error is only 1 usec, I didn't consider it to be that important.

bye, Roman
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