Re: [PATCH V8 02/13] ntp: add ADJ_SETOFFSET mode bit

john stultz
2011-01-10T21:06:37Z

On Tue, 2011-01-11 at 05:45 +0900, Kuwahara,T. wrote:
> On Tue, Jan 11, 2011 at 1:49 AM, john stultz <johnstul-r/Jw6+rmf7HQT0dZR+AlfA@public.gmane.org> wrote:
> > Leapsecond processing is done via an absolute hrtimer. Thus when the
> > time offset is set, the hrtimers that should have expired will fire
> > (just like with settimeofday) and the adjustment will then be made.
>
> How do you convert relative time to absolute time? It's not trivial
> because TAI offset is also a variable.

I don't believe I understand what you're getting at.

The proposed interface is almost identical in functionality to a
userland application doing the following:

offset = my_calculate_offset();
clock_gettime(CLOCK_REALTIME, &now);
newtime = my_add_ts(now, offset);
settimeofday(&newtime, 0);

The only difference is that you avoid the error from the delay between
the gettime call and the settime call. It just adds the offset directly
to the CLOCK_REALTIME.

thanks
-john